Ecology and Populations - Biodiversity semester 2
What is ecology
It is the scientific study of the distribution and abundance of organsim and the intercation that determine the distribution and abundnace that can eoither be biotic or abitoic
What are biotic and abiotic factors
Bitoic are living factors = competition, predation , disease and parasites
Abitoic are non living factors = Temperature, pH, Wind , light
What is evolution
This is the change with continuety in successive generations of organisms and this is done by natural selection which is a complex process where the total environment will determine what members of the species will survive and pass on tbheir genes to next generation
Biotic and abiotic factors proivide the selection pressures for species
At what level can evolution ecology be studied
This can be done individually, Population of the same species, Community which is the population of many different species and the ecosystme is the community in its physical environment
What are observations
This can be as simple as counting mice on the beach and then counting mice near the road and compare the difference and can also obsevre intercations between different organism to make a food web
What are Surveys
This can be done by a Phase 1 habitat surey that measure the different habitats within a larger area and how the diffrerent areas of smaller land are used
What is Correlation
The can be correlation between the environmetal factor and an indiviudual organsism success as the factor changes that can be + or -
Can also correlate the environemtn factor and organism diversity/population that may have threshold effect where correlation start strong but then may plateu
What are the 3 experiments ti look at evolution ecology
Controlled experiment= Can change environment factor and see it changes output of measured factor
Garden Type = Where plants or animals are moved around a location and put in different environment to see how they will respond
Field Manipulations = Remove the eggs of brids and then see the hatching and fledging success are higher for the year after
What models can be used to investigate ecology
Darwin theory of evolution by natural selection
Computer simulated models to see what may happen for the future with different inputs EG predict climate change impact
What is a population
Is a sexually interbreeding or potentially interbreeding individuals
There is the potential for individuals in same population and species to reproduce with each other
It will lead there to be gene flow and there are no isolating factors in the population
What is a species
A group of interbreeding or potentially interbreeding natural populations that are reproductivly isolated from other groups and so will lead to fertile offspring to then mean there will be gene flow and evolution between generations
What is a Metapopulation
These are single populations that will expand every so often and then move outward in size and location:
The source population is where genes will flow from and the sink population means no further gene flow beyond this population
It will occur in fragmented habitat due to local conditions and there is limited migration from the source population
Can get a local exstinction at sink population so then gene flow back to the source and then once conditions improve there will be recolonisation
What does population studying help to do
Can help with conservation management of endangered animals
Management of food security in fisheries if too many adult populations arer fished then there will be no future food sources
Both will help to limit population decline of species
What are the charactersitics of a population
Distribution - the size,shape and location of the populations#
Density- the number of a certain species in a specific area
What is population distribution
The geographic range of the species = spatial range of where they can live
Thius may vary due to environmental factors + may be smaller sub species of a species due to gene flow within subpopulation due to varying conditions
What is Uniform distribution
This is where each individual of a species is equally spaced from each other
They are trying to stay apart from each other to prevent interspecies competition for resources
This is common in very territorial species
What is Clumped distribution
This is where they dont try to stay apart from each other
This may vary due to environmetal factors that is needed by the population:
May be enough resources so no competiton + saftey in numbers for herd animals
Also may be due to sexual reproduction methods
What is random distribution
This is where theyu dont avoid each other and arent looking for specific thing
Large abundance of needed resource
How to mathmatcially work out population density
Density x Area and may be useful as allow to compare areas at different times of the year
How can population be measured - Sampling
Take a sample of a population and then use the samples to then extrapolate to the estimate the actual population size
The more samples taken the greater the accuracy of the estimate
Sampling may be done by a quadrat
What is the mark release recapture method
Capture and mark a set number of individuals in a population and then release them and allow them to re-enter the population and follow their natural dispersion
Then can have another round of capturing and then use the Lincoln/Petersen index
Population = Marked animals x number recaptured / Number of marked recaptured
What is flux population dynamics
Adding individuals via birth and immigration to then lead to population growth and there can be negative population grwoth as well due to death and emigration
This can happen due to spatial expanmsion or retraction or temporal reason where age of population in different areas change
What are patterns of survival
There are higher levels of survival amoung young in dall sheep that show greater level of parental care but then iff there is greater death rate in the young it show lower parental care but then if survive there are fewer predators so live for long time after intial high death chance when young
What is a biome
It is a biological subdivision that will reflect the ecological and physiognomic character of the vegatation, they are the largest biotic communities that are convienient to recognise
They will broadly correspond with climatic regions and distinctive biomes are recognised for all major clinatic reggiosn of the world and will emphasize the adaptation of the living organsims to their environment
What are the 7 biomes of the world
Tundra
Boreal Forests
Temperate forests
Temperate grassland, savannas and shrublands, desert and drylands
Tropical and subtropical grasslands
Tropical and subtropical forests
Desert and dry shrublands
What are the differences between the biomes
The availbailty of water and the solar radiation levels will all change and vary depending on the biomes that you are in so are then all suitbale for different species
What is the global water cycle
Water in the sea will evaporate due to the solar radiation that will shine down on the surface of the sea
This will then lead to then greater water evaportation from the sea where then a large is returned to the sea or land as rainfall
The rest of water will transport over the land as clouds and then as it cools down it will then rain over the land and then gradually work back to ocean via rivers and lakes
This can also be done by polar ice caps and then may be trapped in leaves and soil but all will lead back to the ocean
What are rain patterns
For rain patterns there are the intertropical convergence zones and there are also NE trade winds that meet the SE trade winds and where they meet is the point on earth where there is the most rain
How is there rain in the desert
There is limited rain in the desert but whne it does rain it is due to the decsending air mass that will result in no or limited rain
Rain is very sparse in the desert due to the high heats and large solar radiation so then limited local water cycle
Rainfall will be high around the tropics and then decline as get closer to the poles
How is rainfall distributed in the northen hemisphere
In the summer there are large amoutns of rainafall will be around the tropic of cancer but then outside the summer the largest rainfall will be seem on the equator and then in the winter the large rainfall will be around the tropic of capricorn
How can you get local rain variation
This is due the formation of a rain shadow
This is formed due to the mountain by the seas with wind coming off the sea and pick up water so the side of the mountain facing the sea have a lot of rain but then the other side of the mountain will have limited rainfall so then there will a lack of rain due to the arid shadow
How do you get temperature variation
As you get further from the equator then you get colder temperatures
In the northern hemisphere the winter is colder and vice versa for summer and southern hemisphere
What are variable temperature adaptations
Species will migrate to warmer winter breeding grounds to avoid the colder weather that comes with winter
Birds have large stores of fats of energy storage in their liver and eat more sugary fruit before they migrate
What is global actual evapotranspiration
The actual amount of water that will be evaporated and transpired to a plant community over a time period
This is dependent on water availability and temperature of the area
This is the highest around the equator due to high temperature and large water availability as well as the rainforest trees having large leaves
What are the important factors for an aquatic biome
The important factors are temperature and the salinity so uf the water is fresh or marine water
What are the types of aquatic biomes
Lakes, esturaries, inter tidal zones, coral reefs, oceanic pelagic, abssal zones, rivers and large deep water areas
What are the 3 temperature variations in aquatic biomes
Epilimnion is the warmest water on the surface and is low density water where the currents are
Thermocline is the next zone of the water where currenst have no effect and there is rapid water change
Hypolimnion is high density water that are always very cold and no currents effect the temperature
What can temperature variation lead to in aqautic biomes
Can cause bleaching that can cause loss of plant life like seaweed so then a less sutibale place for marine life to live due to habitat loss, less food source and easier predation
What is the light variation in aquatic biomes
As you get to deeper water there will be less light availble due to blue and green are the lastr light absorbed at the deepest level, so the sea looks blue and red light is quickly absorbed on the surface
Angler fish in deep sea are red so are invisble due to red light not reflected at deep sea and they have light antennae to lure fish to them for food
What is the salinity variation in aquatic biomes
Water is the best solvent so dissolve all the nutrients that are acquired in the water cycle and returned to the sea
In freshwater fish there are more internal salty conditions than the water so the water will move across gills by osmosis so large water needed to be removed from them
In marine fish there are dilute internal conditions so water move out the body via osmosis and have active transport to remove salt from their bodies
What are the selection pressures for a lack of water
On land, if there is no rain then little to drink and this is overcome by having longer loop of henle in the for desert animals so then reabsorb more water from the urine
In water, there is the loss of water due to osmosis and so cartilaginous fish have high levels of urea in blood to keep osmotic balance and bony fish drink more seawater and have salt removed by active transport
What are the 3 approaches to the proximate vs Ulitmate questions
Descriptive questions
Functional How questions ( Proximate )
Evolutionary Why questions ( Ultimate )
What are the difference between proximate and ultimate questions
Proximate - This is is how it works and how it is achived and they are the mechanisms that underpin the trait or behaviour and epxlain the biological function in terms of immediate physcial or environmental factors
Ulitmate - This is why does this happen, in terms of the fitness consequences of a trait or behaviour and whether or not it is selected and will explain the trait in an evolutionary focus
What did Lamark do
He developed a truly coherent evolutionary theory made of 3 factors
Fact - Species change over time
Course - A progressive change where species asced towards humans
Mechanism - The need to produce a change whihc was inhertied in subsequent generations such as giraffe having longer necks to reach higher food sources
Why is their variation in a species
This is due to the specific genes and different environments adn is good so can recognise their own species for mating purposes
How is the ladybird variation occuring
At higher temperatures there is less melanin to cause the black spots being turned off and then at lower temperatures the more melanin genes so then more black spots
There is also genetic difference to allow different reaction to the changing temperatures between different families
What was the voyage of the beagle
Darwin went to the Galapagos for 5 weeks to produce the theory of evolution
What was Darwin evidence for his theory of evolution - Iguanas
There are 2 types of iguanas where there are marine ones that are able to swim and have evolved to remove salt from their body and then Land iguanas that eat cactus to get their water in extremely hot areas of the Galapagos
What were Darwin Finches
These are finches that have evolved via natural selection to then allow them to develop different niches
They all have different beak sizes so then different finches are able to eat different seed size so then less compettion for food between the finches
This then will increase their chaince of survival and reprodcution and then allowed them to develop different food sources
What is the transmutation of species
Natural selection lead to a divergence of charcter for more living beings to be supported by the same area so then more divergence in structure,,habitats and constitution
There is the ability to then exploit more food niches so there are more species and a greater chance of survival
Darwin said this is not goal driven due to the environment but is doen by random gene mutation that may be advantageous or not and drives natural selection
What is species fitness
The number of allele that you pass on relative to the number of alleles that others of your species pass on to the next generation, the more allele you pass on then the fitter you are
What will determine the fitness of an organism
Naturse vs Nurture:
Phenotype = Genotype + environment
Variation in terms of sexual reproduction so meisosis and theb mutations
How has the peppered moth evolved over time
Before the industrial revolution then the moth were all white to blend into birch trees that are white, but then all around the city there were factories that pumped out soot and turned the tree black so then the white moths were more vulnerbvale to predators so then they evolved to have black wings to then blend into the city better
The moths that stayed in the country remained white and the city ones stayed black so both matched their environment and allow them to camoflauge well
What are the 3 conditons of evolution
Variation will cause a difference between individuals in both genetic and environmental ways
Variable traits must be heritable onto the next generatiom
Variation in fitness in term of survival and reproduction
Evolution is a complex process in which the total enviornment dtermines the member of the species that survive to then reproduce and pass their favourable genes for the environment onto the next generation
What are adaptations
It is a product of evolution by natural selection that can have both trade off and contraints
It is a heritable trait that is evolved over time to then maintain or increase the fitness of the organsim
What are the 3 types of Selection
Directional is where the curve shift right due invasion of a new trait
Disruptive is where there are 2 peaks at either extreme and can lead to new species and adaptive radiation
Stabilsing is where there is no evolution due to large peak at the mean
What is adaptive radiation
This is selection for changes in beak morpholgy or 2 very differemnt features within a species
It can then lead to different species over many generations anf they occupy different niches buyt it can lead to inter or intra competition over a niche due to new species has been introduced to already occupied niche
The competiton can be limited due to target different niche so then different species that have different food source in the niche so then limit competition
What is convergent evolution
Where 2 unrelated animals that dont have a common anscestor develop the same phenotypic trait such as Toucan and Horn bill both have very long beaks
Or unrelated organsims look similar like sharks and dolphins
What is the equation for total phenotypic varitaion
Varience due to genetic effect + Varince due to environemental reason = VP= Vg + Ve
Hertibality = Vg/ Vc and will tell how likely a trait is to be passed on to next generation
What is heritability and phenotypic plasticity
Heritability - A trait within a population is the proportion of observable difference in traits between individuals within a population due to genetic differences
Plasticity - Is phenotypic change due to the environment
What is evolution
This is a change in mean or varience of phenotypic traits across the generations due to a change in allele frequency
What is the Mendel Principles
Principle of segragation of unit characters: this means that due to dominant and recessive genes so a red and white plant wont make a pink plant
Principle of independent assortment: This is a way to predict allele phenotype as it will alwasy be the dominant allele shown when either homozygous and heterozygous but then if its a recessive allele then it has to be homozygous genotype
What are mutations
Mutations may appear over and over with some more than others
Adaptations and natural selection and evolution rate depend on generation time and length of the reproductive life cycle
There is quicker evolution and mutations in flies that compared to elephants
What is the problem with Darwin Theory
Darwin thought there was phenotypic variation due to environemntal variation but actually is due to the mutations of genes
Maintenence of variation and thought blending of parental genotypes to lead to blending phenotype but this is not true due to independent assortment
What is Heritable variation
Continuous vairation - There are many genes and a high environmental component
Discountinous variation - They have few genes and a low enviornmental component
What are the ways to calculate gene frequencies
Morphological data, Enzymes, DNA amnd Behavioural
What is the Hardy Weinberg principle
Genotype frequncy will remain constant if :
Mating is random
No Mutations or migration so no gene flow
Large populations
No natural selection
What does the Hardy Weinberg principle do
It enable to predict allele and genotype frequency from 1 generation to the next in absence of evolution
What is the formula for allele frequency
There are 3 types of Genotypes:
P - Homozygous dominant
H - Heterozygous
Q- Homozygous recessive
There are always 2 allele:
A allele frequency p = P + 0.5H / N
a allele frequency q=Q + 0.5H / N
N = Population size
p+q = 1
What is the equation for Hardy Weinberg principle
p2 + 2pq + q2 = 1
This can be used to prove evolution if genotype frequency not same as before random mating
What happened in the Cambrien explosion
The first animal came about 565 mya
The pre-cambrien era was called the ediacaran fauna between the 506-543 mya thgere was the Cambrien explosion
There was evidence for proliferation of animals with a backbone and a hard skeleton
The ediacaran fauna was made of the bilateral symmetry such as worms and molluscs before the cambrein explosion that lead to all phyla today
Why was the cambrien explosion not explosive
The molecular clock and the changing of bases lead to the idea of the speed of diversification to then be able to measure the amount of changing species that have diverged from each other
This has indicated that vertabreates are 900 mya were lava like organsims so were not fossilised
There is also disconjunction about when animals appeared due to first fossil from 565 mya
What was the Cambrien radiation
It was the 1st phase of phanerozic era ahnd there was the rise of small predation so then small animals developed armour so they were fossilised
Formation of complex eyes to avoid predation and easier to find suitable mating partner quicker so more survival chance
Evidence for species raditon as some arthropods became fish sop more species diversity
What causes the cambrien explosion
Atmospheric changes that lead to the explosion
Also metazoan animal cell emerged from cambrien explosion
There were vacant ecological niches that were then filled by hard shelled animals that could be fossilised
What is the species area relationship
If there is a larger area of land then there is a greater number of species and the number of species is balanced at equilibrium based on new species and some species going extinct
What is the evidence for organims existance
Fossil evidence - This will depend on the availability of sedimentary rock and so if there is there is some there then organsims did exits if they fossilised
Can also use the molecular clock
What are reasons that species go extinct
The Red and Queen hypothesis is that species are outcompeted and so they will then go extinct
Species have to keep evolving so they dont go extinct and this is due to competition and prey/ predation and once a species is extinct they cant come back
Non biological is also due to natural evenst that change the physical environment that lead to mass or local extinction
What are the consequences of extinction
There will be a vacant ecologicla niches and then due to adaptive radiation this niche will then be filled by another species
The adaptive radiation may then lead to new species evolving over time
How did the Dodo go extinct
This was due to Human dutch activituy in Mauritius as they introduced pigs, cats, rats and goats into the Dodo habitat and they then destroyed it and all the dodo were extinct within 40 years
This then lead to the extinction of the Calvaria Fig tree as they had co-evolved with the Dodo as they relied on the nutrienyts of the Dodo to germinate their seeds
What is a mass extinction event
This is an extinction event where 60% of all species go extinct due to the event and the event will mark the end of a period of time and start a new period of time, this is due to fossil records where some fossils are present or no longer present in the future fossil records
What happened in the Ordovicran period
There were 2 extinction burst between 450mta - 440 mya where 60% of all marine invertabrates went extinct due to no land life at the time
This mainly effected Bivalves, echnioderms, corals and trilobites and what followed was major continental drift that caused widespread glaciation and drop in sea levels
What happened in the Devonian period
This was 365 mya and mainly effectec 50% of all life mainly being marine life, such as agnathna and placoderm fish, conodotos, trilobites, ammonites and reef builders
There was major environmental change due to anoxia in lower ocean levens and sea level change
What happened in trhe permian era
This was 251 mya and lead to 70% of all land species and 96% marine species going extinct
This effected ammonites, trilobites, echnoderms, brachipods and insects and this is the only insect mass extinction event
Caused Volcanic acticity as well as methane and anoxia release
What happened in the triassic era
This was 200 mya and wiped out 50% of all species mainly conodontgs, reptiles and amphibians and cuased volcanism and climate change
What happened in the cretaceous era
This was 65mya and wiped out 75% of all species
It badly effected ammonites, belemnitesm dinosaurs all gone bar birds as well as all marine dinosaurs as well
Cause large spread volcanism
What are recent extinction eventy
The human meteorite
There was is a background extinction that mean then in 100 years could lose 60% of all species
Tropic rainforest are at large risk due to most diverse but also most at risk due to human activity
There will be mass habitat destruction, over resource exploitation then then lead to global climate change
What is coevolution
This is where 2 animals have coevolved together and can either by helpful for both species in a symbiosis of the 2 animals that benefit from each other, or it can be way harmful when 1 species will be a predator for the other species
What is a coevolution symbiosis
There will be an ecological coulpling of 2 or more species such as Dodo and Calvaria fig tree
There are 2 types - Mutualism where both the species will benefit
Commenalism where 1 species will benefit and the other species is uneffected
This can become very specific as flowers with different length spur can only be pollenated by 1 moth type that has right tongue length
It can lead to phylogenetic tree similarity
What is the definiton of coevolution
A chnage in gene in 1 species that then will cause a gene change of another species then then in turn lead to evolutionary change of the 1st species
It can cause closely related phylogenetic tree due to host/parasite, pollinator,flower or prey/predetor relations
What are the types of coevolution
Plant and pollinators, Plant and dispersers, Plants and herbivores
Where is there an arms race coevolution
This will occur between hosts and Pathogens + Prey and predators
What is the Red queen hypothesis
To evolve as a species the prey has to show a moving target that predator cant reach and so this lead to an antgaonistic co-evolution that is shown by the mutual escaltion of investements in terms of the energy to attack and then the energy to defend for the other species
What is the normal sequence of events for a arms race
The Parasite wil reduce the fitnes of the host species
The host then will require a defence mechanism against the parasite via mutation and gene recmobination so then lead to greater host fitness and this trait then spread through generations
The parasite then gain a new mutant and this spread through their generations and cycle will restart again
What are the types of defence
There is coloiuration and shape to provide camoflauge and there are 2 types: Cryptic to blend to environement + Masquerade to then resemble another object or have bright colours so dont look good to eat
Protective armour/spines
Chemical defence and aposematic colouration
Mimics - Batesian and Mullerian
Behavioural such as fleeing, deimatic to look intimidating and Thanatosis to fake death
What are example of cypsis defence
White tailed deer fawn to hide in deep undergrowth
Peppered moth either white or black depending on city or country
Spider camoflauge to the tree bark to hunt and avoid predation better
What is an example of disrupitve colouration
In Zebras - it is disruptive to flies that will try to bite them
Types of birds also look same as environemnt to confuse predator as well as in some fish
Stone fish for hunting as well use this as well
What is the deflection of an attack
Where the prey direct an attack to a non vital area of the body by ghaving false eyes and other features in hope that the predator attack the wrong area of the body
How can armour act as a defence mechansim
Woodlice and Millipedes have an armourded body and can also roll up into a ball that is fully amoured all the way around and keep the important areas of the body insude the sphere and makes them hard to hunt
Can also have the use of spikes in animals such as hedgehogs and holly bush to avoid the berries being eaten
How does a chemical defence help
There is toxic substanfces that animals and plants can release to avoid predation and also if digested can also be toxic to predators and these are unapparent species
Apparent species have long term avoidnace due to having more complex chemicals that cause greater damage to the hunter
Can also have aposematism where they have bright colours so then animals know not to attack due to poisinous
What is mimicry
This is where coevolution lead to mimicry of some species to another species so they aren’t hunted due to predator think is another type of species that they don’t want to eat
Can be seen in wasps and hoverflies
The normal will be toxic and the mimicing creature wont be toxic
What is retaliation
If elephant go near bombardier elephant then Beatle will release acid and deter the elephant to move away from that area
Can have group defence by safety in number tactic to make it harder for you to be hunted than if on your own
What is deimatic behaviour
Defence postures or other visual displays that will intimidate the predator by colour change
Pufferfish
Type of moth that have large fake eyes on wing so look like monkey face
Thanatosis is where animal pretend to fake death so then the predator will leave it alone
Usually have more than 1 defence type like the horned lizard
How can population growth be projected
This can be done via mathmatical projects and can show either positive or negative population growth or it may stay stable as well
Why are population growth models used
As it is impossible to count every single individual of a species or population in a habitat so models are used to accuraly predict the population levels
They will gather infomation from species life history such as Semelparity ir Iteroparity
What is an open population
There will be population immigration and emigration and will lead to gene flow between different populations
What is a closed population
There is no immigration or emigration and the population may be closed due to geographic boundaries or there is no longer any gene flow due to human interference
What is the geometric population growth model
There is appropriate to estimate the population growth in annual breeders so there is 1 new generation per year
It will assume the birth rate is greater than the death rate as well as the fact that the births are independent of the population size
It may then lead to overestimation of the population
What is the exponential population growth model
This is used for organism that have continuous reproduction and there is no specific breeding time and it can happen all year round
It will assume there is no emigration or immigration and there is no death due to limited resources or predation
This then mean that the change in population is due to birth and death rate and then use the difference between them too predict population size
If R is greater than 0 then population increase and if less than 1 then its decreasing
What effects population density
Population density is the number of indiviudals in an area and it can be effected by:
Indepenendent factors such as weather and density independent disease
Dependent factors such as food and habitat competition, Density dependent diseases as well as predation
Why does density dependence work in a large population
Birth rate will be independent of density and death rate is dependent on density, then a high carrying capacity
If birth rate is dependent on density and death rate is independent on density then a low carrying capacity
If both are dependent on densityt than a medium but stable carrying capacity
How does the allele effect change density dependence in small populations
There may be the situation where the death rate increase and birth rate remain the same
Birth rate could also increase and death rate stay the same
Death rate can also increase and the birth rate may then decrease and this will be all be seen in social species that need a certain size of population for the reproduction to then take place
What is the logistical population growth model
This includes the concept of populations that are coming up to reaching their carrying capacity
As the population will increase then dN/dt will get smaller and K will also = 0
If for the values N is less than K then population growth and if smaller then will be population decline and if then r=0 due to N and K being the same then population stay the same
Hoe can we compare age specific account of mortality to compare different population ages
X= Age class of population and then table the:
Number of survivors during the sampling
Number of surviving individuals as fraction of the orginal cohort
Difference between the alive indiviuduals for any age class and the next older age class to know how many died
Number of indiviudals that died during tiem divided by number that were alive at the start to get age specific mortality rate
What is life history
These are significant features of the life cycle that an organsim will pass through with particular reference to survival and reproduction methods
What is the life history theory
These are the many physiological and behavioural traits that cna be understood in the context of the major characteristics that define the life history of an organism
What is a phenotypic reaction
This how adapted a phentype is adapated for a reproductive success
There can be extrinsic interaction are the age specific rate of birth and death
Intrinsic intercation are the trade off between certain traits
What is Semelparity
This is big band reproduction where there is a high reproductive rate per event like in plant due to pollination can carry large distances and be very succesful
What is Ireroparity
This is where there is reproduction for successive years and there are fewer young produced per event per year but then there is greater level of parental care this is seen in animals
What is R+K selection
R selected - Favoured for rapid reproduction so have a smaller size, early maturity and semelparity with mkany offspring
K selected- Favoured for ability to make larger proportional contribution to a population that remain near the carrying capacity so for larger size and a deferred reproduction as well as iteroparity and few offspring
R selected habitat are very unpredictable and K selected have lots of competiton
What is Age first reprodiction
This is where survival rates are higher in older first time parents than younger first time parents, this is as they have had more time to grow and get larger so then are able to have more offspring and get a larger litter size
If though there is younger reproduction then there is quicker maturity and so then lead to shorter generation time and then faster evolution rate
There is then a trade off depending on evolution stage strategies and how species has evolved in their current conditions
What is insurance offspring
This is where some species produce insurance offspring in the chance that then some species wont survive and so if this happens they then ha the optimal amount but if the conditions are good then can lead to having too many offspring
How does species size effect life history
The bigger the species size then the slower the life history as well as the reproduction time
What is behavioural ecology
This is where there is the use of phenotypes to show evolution
Ultimate questions show that behaviours evolve to max the fitness of an individual and there are 2 principles for this:
Quantify variation in behaviour and indiviudual variation to test adaptation
What is individual fitness
Darwin fitness is measured by the reproductive success of an indiviudal either asexual or sexual
Sexual is favoured in unpredictable environment but can cause sexual conflict between males and females over investment in the offspring and so there has been antagonisitc evolution and then sexual selection
What are the 3 mating systems
Monogamy is where there is biparental care of an offspring
Promiscuity is where there is males and females with many partners and so there is no post natal care
Polymay is where there are multiple mates or enough resource to attract many mates for them and the mating partner is the one that best ability to use this potential so attract the mates
1 sex will be free from parental care to focus on intrasexual comp and then resouce competition
Polyandry is where male does parental care and Polygyny is female does parental care
What is sexual selection
The selection on mating behaviour, either through competition among members of one sex for access to members of the other sex or through choice by members of one sex for certain members of the other sex. In sexual selection, individuals are favoured by their fitness relative to other members of the same sex, whereas natural selection works on the fitness of a genotype relative to the whole population
How is reproducton more expensive for females
This is due to cost more enegry to produce eggs that to produc sperm as well as eggs being larger so need more energy
What are the limits of reproduction
Females – Number of eggs or pregnancies
Males – number of females that they are able to persuade to mate with
What is the clutch size and the environmental effect on parental investement
Lack believed that clutch size depends on availability of resources
Cody thought that clutch size is large to take advantage of beneficial environmental conditions
Ashmole believed and most evidence for that Clutch size directly proportional to seasonal variation in resources
What can estimating popualtion growth models show
Positive growth - Where it increases
Negative growth - Where it decreases
Stable - No change
The models will show every individual of a species in a habiats so they are accurate and use some factors from the life history like semalparity and iteroparity
What are the 2 types of populations
Open- There is population immigragion and emigration that will lead to gene flow between the different population
Closed = There is no immigration or emmigration potentially due to closed geographical regions or no longer gene flow due to human interference
What is the geometric population model
Population at time = Initial population x Geometric rate of increase
This is a way to estimate the population growth in annual breeders so there is 1 new generation per year
It assumes that birth rate is greater than death rate as well aqs the fact that they are independent of population size
This likely cause overestimation: shown by wolves in yellow stone park, where no gene flow and they were killed if left certain area as well as being to much prey and low predator number
What is the exponential population growth
This is used for organsims that have continuous reproduction as there is no specific breeding time
It will assume no emigration or immigration, No death due to limited resource or predation
This then means changing populations are due to birth and death rate so can use the difference between the 2 to predict new population size
If R is greater than 0 = population growth, if = 0 then stay the same and if less than 0 then population decline
What are the effects of population density
This is the number of indiviudals per unit area
Density independent factors: Weather, independent diseases
Density dependent factors: Resource competition, habitat competition, Dependent diseases, predation
What does density dependence show
This will work best in large populations, the graphs are able to show then which of the birth rate or death rate is dependent on the population density or if both are dependent
What does density dependence in small population show
This wil change the dependence on density in small populations due to the allele effect
There can be instances when birth rate will increase and death rate stay the same or vice versa, as well as DR increase and BR decrease which is shown in social species that need a certain population size for reproduction to happen
What is the logistic population growth model
This include concept of population that are near carrying capacity
As population size increase then value of dN/dT gets lower and K =0
N is less than K = population growth and if N is more than K and r is negative than population decline back to carrying capacity
If N+K then r = 0 so no change
How to compare different population ages
Can use life tables that allow an age specific account of mortaility
X = the age classes of the population
2nd column = The number of survivors during the sampling
3rd column = Number of surviving individuals as a proportion of the original cohort
4th column= Difference between the number of individuals alive for any age class and the next older age class to tell how many have died
5th column is the number of individuals that died during the time divided by the number that were alive at the start to get an age specific mortality rate
What is Historical Biogeography
The earth has not always looked like it does now, as it is constantly moving due to tectonic platers and continental drift
This is shown by fossil records and their location of being found to show pieces from same thing are in different places
What is island biogeography
Island Fauna is impoverished and the species there have found their way to inhabit the island so then they dont have the normal predator or competition pool
But there are different selection pressures and gene pool
This can lead to gigantism in rodents and dwarfism in rabbits so each indiviual of a species can have a particular niche
They can serve as a natural experiment to test predaictions abpout evolution of life
How does being on an isnland effect population growth
On a new island there is higb rate of immigration as each species is new, and then as more species arrive and settle then the rate of immigration will lower due to less niches to occupy for new species. Rate is also determined by distance to land so lower on larger closer island than isolated small island
Exticntion rate is determind by island size as itn gets smaller then more extinction rate if population get too karge then more exticntion to bring back down to species equilobrium and vice versa
What is the species area relationship
S = C x A^z
If a high Z value then species richness increase rapidly in an area
If there is low Z then species richness gradually increase in an area
Can be used to compare between taxa and habitat
What is Landscape ecology
Landscape = An area that is spatially heterogeneous in one factor of interest
Landscape ecology- The study of landscapes taking into account of the ecology of the biological population
Disturbance create spatial heterogeneity that lead to a normal state and so a non-equilibrium
Matrix = Area that will surround the habitat
Movement between fragments will depend on the quality of the matrix
Scale can be described by
Grain is the finest resolution for viewing an event
Extent is the overall size of the study
Whar are fragemented forests
There will be a lower species richness than unfragmented forests of the same size byt the matrix has an effect as well
The smaller the fragment size then the fewer species so then largest number of oxtinctions
Edge effects:
There may be edge of the fragment adapted species that benefit from that area but others may not
What are ecological traps in fragmented forests
A proposed situation where organisms may be induced to settle in low quality habitats due to have some advantages but is low quality, They are unreliable, So species get trapped in attractive but low quality habitat
The edge of fragment is example of this:
Birds that nest along forest edge historically found in forest opening due to fire maintained successional habitat
But greater human caused edge habiats are not high quality so trap the birds
What is human ecology
The scientific study of the relaitionship between the indiviudal humans and human soceities and their external natural, built and social environments
What are the 2 important human revolutions
These are agricultural and industrial revolution both changed the way that humans live and worked on a day to day level both however are linked to human induced climate change as they both lead to:
Increased atmospheric carbon, deforestation, world population and meat/fish harevst and consumptiom
What has a growing population led to
There has been a lowered distribution of forests due to need for more space to live and to provide resources, there has then been a decline in habitat variation that then lead to less diversty = extinction
What should the rate of speciation ideally be the same
Ideally should be the same as rate of extinction as both are natural processes however due to the rate of extinction being larger than speciation leads to:
Less genetic diversity and less ecosystem diversity
How can conservation of biodiversity be done
Endangered animal lists, reintroduction of certain species, conserve hotspots in area to protect population and communities of endangered animals
What are ecosystem services
These are the services that the environment provide humans:
Green space, food and cooling and green pathways in cities are all provided by the environment
What does genetic diveristy come from
Selection pressures either directional or stabilising willl lower diversity and if disruptive then increase diversity
Mutational will increase as greater gene flow generated
Meiotic drive, non random mating and random genetic drift all will lower diversity
How to maintain genetic diversity
Populations are not in evolutionary equilibrium in respect to directional and stabilisng selection
Deleterious mutations and selection balancing
Disruptive selection is common due to: Frequency dependent selection and a fluctuating environemnt as well as heterozygous and homozygous advanatges in over or under dominance
There can also be the flow of genes from another population
How is diverstiy effected in small populations
They have a lower genetic diversity due to a smaller gene pool and it means that genetic drift will have a greater effect in small populations and may cause random fixation of alleles and a loss of heterozygosity
Why is there lower genetic diversity in small populations
The genetic varitation will decrease over time as well as molecular evolution decreasing over tiem as less mutation oppportunities
There is also inbreeding depression that cause reduction in survivla of offspring from relatives and also more homozygosity
This mean the genetically effective population is smaller than the actual population that then change the mating system as well as ebign greater bottlneckle effect
What is population viability analysis
This is the estimated probability of extinction over a time period based on the exponential, density dependent intercate predator prey, metapopulations or age dependent models
Use estimation variatin in demographic parameters to add noise to a stimulated population
Can assess if the species is falling below the arbitory critical value called the quasi extinction threshold and then from this point there is human intervention
What are the human mediated changes that can be carried out
Habitat degradation and destruction
Habitat fragementation
Overexploitation
Introduction of non native species
What is habitat degradation
The imvolves the importance immigration that can be treated by control, corridors, pseuodocorridors and fragments
In metapopulations there are fragments are femald and male both have high immigration to new populatiosn so greater population stability and they are less likely to ge extinct due to larger patches so more space for individuals and more diversity
A greater patch effect so then greater immigration from nearby populations
What is the allele effect
Population density effect to small populations size that lead to harder conservation ecology
The social dysfunction and failure to mate succesfully occur in some species when their population density falls below threshold
There is a lower mating success in low density populations
What is over-exploitation
Thus may be due to farming or overfishing and may lead to extinction due to:
Highly fished areas there will be soime fish thyat will die even if not the target due to maybe a lack of food source anymore or greater pollution
What are non-native species
These are species that have reached an area by accident, human transport, deliberate human introduction or they have arraived by natural disperal from non native populations
How do non-native species survive
Enemy related hypothesis- They can disperse without their natural enemies from there native region
Evolution of increased competitve ability - Fewer herbivores and so then can allocate resources to survival and reproductim so greater competitve ability for plants
Resource hypothesis - Experience a more idela combination of resources in the naturalsied habita that in the native natural habitat
What are the 2 types of thermodynamics
Kinetic and Potential energy and this energy cannot be created or destroyed
When energy cannot be passed on any further there is then an increase in entropy due to the increase on everness
2nd Law= In a closed system entropy will increas but living organsims will resist increase in entropy as organsims are not closed system
What is primary production
The rate of which biomass is produced by photosynthesis and chemosyntehtic autotrophs in the form or organic materials
What is Gross primary production
This is the total energy that a plant will create
What is net primary production
This is the total energy that is available to species that eat the plant
It is calculated by: NPP= Gross primary production - Respiratory loss
NPP = Delta SCB + D + C
SCB- Increase in living plant biomass , D = Death of plant , C = Biomass in consumer organsims
What is the standard crop biomass
This is the amoutn accumilated organic matter in the area ata given time and a habitat can have a high SCH but a low productivity of production
What will effect primary production
Bottom up effects: Precipitation, nutrients, Temperature and Light effects
Top down effect: Consumers
What is secondary production
This is the net production by hetertrophs that get their energy from the primary producer so the available NPP
If there is a high level of primary then high secondary production as wellm
How to calculate secondary production
Food ingested = Assimilated + Waste product
I = A + W
A = Production + respiration loss
What are secondary production efficiency calculations
A/I = Assimilation efficiency
P/A= Productiob efficiency
In/Pn-1 = Consumption efficiency
What are food chains
There is a creation between eltonian pyramid that show the energy passed between the trophic levels of an ecosystem
This may limit hwo long food chain will be as will run out of energy eventually as most is lost between levels
What are the 3 producitvity hypothesis
Productivity hypothesios =The lower the producotivity system then the lower the producivity per unit size that ncreases as system producitvity increases
Ecosystem size hypothesis = As food chain increases then the size of the sustem increases
Producitve space hypothesis = In high produductivity systems there is a longer food chain and vice versa
How is the length of the food chain determined
The main size of the ecosystem and not the productivity is the main driver for food chain length
In aquatic the ecosystem is more important for food chain length and in terrestrial the productivity is more important for food chain length
What are trophic cascades
Top down control is where the population of a predator increases then lead to lower population of the prey that then leqad to greater popyulation of the prey food source, so then a smaller population of their respective food source
What is a community
This is a group of populations different species that are living together in a specific environment
They can intercat via competition, predation, parasites, symbiosis so get trophic and spatial relations
They can also be guild which is a group of species that have a similar way if living and explout similar resources
Some species will be more common than others but most have an intermediate abundnace
What is species richness
Is the number of species found in the area
The sample size is important for determining the species distribution curve so then show greater differnce between common and rare species of the community
How is species abundance measured
Richness - the number of species in an area
Relative abudance = What % if a species contribute to the overall number of species in a community
Eveness= Degree to the distribution of individuals between species is equitable
What is species diversity
This a function of both the species richness and eveness in the community but in only 1 number that is calcukated
How is species diversity calculated
Simpson Index: Id D is low then a low diversity and if N near 1 then high diversity
Shannon index = If H new 0 then low diversity and if H near Ln(species) then a high diversity
Eveness J = If J= 0 then low diversity and if = 1 then a high diversity
How does diverisyt correlate with habita complexity and intermediate disturbance hypothesis
If there are low levels of disturbance then will allow competiton to lower diversity
The hypothesis will predict that species diversity wil be highest at teh intermediate level of disturbance
If there is high level of disturbence then there will be lower diversity
What is a food web
These will show what species are eatne by other species and that they asre eaten by as most animals have mulitple predatirs and then also multiple different food sources
The food web shows the complex and indriect relations in the community
How do wolves effect salmon populations
There is an indurect relation due to wolf population effect salmon number even though the wolves dont eat salmon
Wolves will prey on deer so then they will prevent the deers from breaking down river banks and eating saplings of trees
The trees then wont grow on the river banks and provide shade from branches to allow the salmon to hide and breed so makes then more vulnerable to predation if there are no deers present
What is a physical community structure
Zonation is the divison of an ecosystem into layers that experience particular abitoic condtions that are different to other zones of the ecosystem
What is exploitation - antagonistic evolution
This may involve prey defence against predators such as: Physical, chemical, morphological, Behavioural
Predatory hunting tactic such as ambush, stalking and pursuits
They may also use cryptic colouyration as well morphologicla triats like ressembling prey and venom
What is Herbivory
This is the predation an autotrophs where the plant is not killed but much lower fitness
The plant respond after herbivore attach so need more energy to make more leaves and then any remaining energy to make seed but overall lower fitness
The plant can defend by physical or chemical defences
The secondary chemical defences of compounds the plants don’t need to make but is worth it for defence = Nitrogen basec compound, terpenoids, phenolics
What are the 2 population growth model
There are 2 population growth models:
Predator - birth rate and mortality rate
Prey - Mortality rate due to predator to find rate of predation
The number of prey will effect the number of predator and is in constant cycle = Red queen hypothesis
What is the red queen hypothesis
Where prey number increase lead to increase in predator number and if prey go down then so does predation
This is in constant cycle
Shwon by the canadian Snowshoe hare andthe Canadian Lynx
What are the hypothesis for population cycles
Sun spots will limit the sunlight so less plants grow = Incorrect
Biotic intrinsic change in behvaiour = Incorrect
Biotic extrincisn predation so prey population cycle as well as different temperatures change the food that year = Correct
What is the Lokta Volteraa model means
This means that more prey get more predators and vice versa for decreasing populations
The functional response is that if more than 1 type of specific prey then the predator will eat more of the abundant prey by the predator so then can change dietary taste for that year
What is comunity ecology
Community is a general term applied to any grouping of populations of different organisms found living together in a particular environment; the biotic component of an ecosystem. The organisms interact and give the community a structure. Globally, the climax communities, characteristic of particular regions, are called biomes
Guild = Group of species that depend on the same resource for survival and reproduction
Functional Group = Group of species that performs the same function within the ecological community not necessarily the same as a guild
What is the community structure
In dung beetles there are 7000 species of 3 - fucntionla groups the most important being the: Dwellers, Tunnelers and Rollers
Dominant species = These are the foundation species that have high abundance or biomass so effect the community structure such as spruce tree in boreal forest
Keystone species = One whose have lower abundance but have large effect and is disproportionly large effect to abundance in the community such as: Piaster- These are a predatory starfish that feed on mussels and are responsible for maintaining the local diversity of species in the community as without the mussels would colonise and take over the community
Whar are types of food web
Specialist =so each species only eat 1 or 2 animals – There are more species than lines in the community food web
Generalist = Where there are more speices that eat more of the community and less picky so more lines than species
What is symbiosis
Is where dissimilar organism live together in close association and will embrace all types of mutualistic and parasitic relationship
What is Mutualism
There is a host and parasite that benefit from the association such as plant and pollinators – one cant survive without the other
What is commenalism
Parasite benefit from the relationship but the host is not harmed such as clownfish and poisonous anemones, this will exist when the parasite from associating with host species so the host never found without the parasite but the parasite can be
What is Parasitism
Parasite harm the host of lives at the expense of the host such as corn smut fungus on corn
What is Parasitoid
Parasite that cause the death of its host such as braconid wasps on tomato hornworm, the parasitiods are often insect larvae timing development so they are ready to pupate and eat the whole inside of the host as they develop
What is Phoresis
Parasite is transported by the host where neither are dependent on each other but they travel together
How is mutualism used for resources
Pollination for bees and wasps, in Coral and Zooxanthellae as coral feed on zooplankton buyt that only gives 10% of needed energy ansd rest comes frokm the zooxanthellae in return the coral offer a place to live
Legumes and Rhizobium
Plants and Micorrhizal fungi as both are needed for the plant to get nitrogen that is fixed by the bacteria so plant can use it in retrun the plant give the bacteria glucose
How is their mutualism for habitat
Acacia tree and ants:
This benefit the plant due to get enlarged thorns for protection , enlarged nectaries so more pollen spread and get beltian bodies
Thorns are good for the ants to live in and more nectar so more food for the ant so both benefit
New ant colonoes are formed when queen ant finds new acacia tree and will excvavting an entrance to a thorn and lay her eggs there and use the nectar to provide food
The ants help to stop other plants grow around the acacia plant so then plant has less competition for resources as well as also faster rate of tree growth and shoot increase survival chance
How is their mutualism for both habitat and resources
Acacia can have relation with ants, N fixing bacteria, bees and mycorrhizal fungi
Coral and Zooxanthellae- there are also crabs and pistol crabs that live in coral as well: This lead to much less attack on coral when crustacean present due to being protected from shrimp, the crabs take 40% zooxanthellae energy but worth it for the protection
What are mutualism cheats
Actor = Providing a benefit to another but energy cost for itself
Recipient will receive the benefit from the actor
Selection favours: Reciprocity will prevent cheating as if the act is not recprocasted with mutual benefit then selection againts this association, and this is shown in nectar robbers that have a lower pollen transfer
What are the mutualsim environmental effects and disruption
Effects: There is a high benefit inhospitable and highly stressful areas
Disruptions: Pollination as an ecosystem service, as the honeybees will naturally pollinate farmer crops and lead to 400 million worth of crop for farmers in rape seed oil sales due to honey bee pollination
Coral reef bleaching will lead to coral breakdown caused by algal mutualsim caused by increased light and temperature will prevent the alagl passing e- in photosynthesis so get o2 build up and they go to radicals that then destroy coral
What are the benefit of commenalsim
This is where 1 species will benefit from a relationship:
Can provide a way to get food: - Seabirds feed from dolphon bait trail
Also get a place to live and reproduciton vai seed disperal for plants
Example = When cows egret birds love round cattle that kick up, all insect when they move for the birds to eat so only benefit for the birds
What is intraspecific competition
This is competiton amongst individuals of the same species for a limited resource:
There is a scrambloe competiton where all individuals declien in fitness, contest competiton where only some individuals decline in fitness and some wont
There can also be exploitation and interfence and will be density dependent as when get more individuals then a lower fitenss of them all as more competiton
How does intraspecific competiton effect territory
Home range - an area an animal will use for only a year
Territory - This is the defended area part of a home rmage within an area for a specifc individual
Individuals can gain or lose territory if they dont defend or there is space available
New species coming into ecosystem will have to fight for territory and will be fought away by species that occupy the territory already
What is interspecific competition
This is competiton between 2 species
What are the different types of niche
The fundamental niche is where = The set amount of water and food needed for a healthy lifestyle for an animal
Realised niche = This is when there is competition so there is the bare min of food and water for the survival of an organsims
What is the gause Principle of competitve exclusion
2 species in identical niche cannot coexist together and one will be forced to change niche so no 2 species can have the same niche it will lead to competition where 1 species will be excluded from resources
What are the effects of Gause principle
It will have negative effect on 2 or more populations:
There are 6 types: Consumption of shared resource, Pre-emption so the 1st to arrive will win, Overgrowth where 1 grows over another, chemical where 1 species harms another, territorial whe one deters the other, Encounter where there are non territoral meetings
What happens when 2 species share the same niche
2 species in identical niche cannot coexist together and one will be forced to change niche so no 2 species can have the same niche it will lead to competition where 1 species will be excluded from resources
How can a niche be taken
There may be a non native/ or alien species that is introduced
These are oftne better competitors so take the orignal niche in direct competition for the resources or indirect competiton
This is seen in red and grey squirrels
What is succession
This is the directional and sequential change in vegatation structure over time either due to environmental change or as result of intrinsin properties of the organisms there, so will go from bare rock to broadleaf forest over time
The changes have to be longer than seasonla chnages but shorter than changes due to climate change effects
What happens in succession
In early pioneer species there are is a hugh growth rate, high disperal and reproduction rate, fats developemnt but the plants are short lived
In late species there is slow growth rate, low disperal and reproduction but they are long lived and have a higher competitve ability that other planbts there so outcompete them for resources
How does succession lead to niche changes
Succession will work due to at each point the new plant that enter the ecosystem will create a new niche for then new species to then come and enter after and so the new niches are occupied by the new species in the community and the old species will die out as their niches disappear
What is Primary succession
This is whyere there is colonisation of an area of land that had previously not been inhabited such as new land from post glacial rock or volcanic eruption area
What is secondary succession
The colonisation of an area of land that has been previously been colonised by plants and so there may be resources, seedbanks and roots in the soil already. May be seen in abandonded farm fields
What is cyclical succession
This is where the succession is a cycle due to having frequenct diusturbence in the area, so go from pionner speceis to then climax and then have disturbence sp go back to bare rock and the pioneer species
This is very present at rocky shore lines due to the action of waves that can cause disturbence
What is successional change determined by
Chance evenyts and other independent processes, emergent properties and species intercation, How predictable is the succcesion so is it stochatic or deterministic
What is the Relay foristic model
This will show at what time the different species will enter the community and what time a species leave
It shows only 1 species present at each time so previous species have to leave before new species can enter
This is stochastic as dont know the time or what species are going to enter the community so is better for primary succession
What is the initial florestic model
This shows that all the species over the lifetime of the community are present at the very start ansd it shows how their abundance will change over time
This is deterministic as already know what species are going to be present and take over community at some point
Better for secondary succession
What is the intermediate disturbence hypothesis
This is where the highest biodiversity in an ecosystem will be when there is the intermediate level of disturbance in that ecosystem, there will be low biodiversity when high or low level of disturbance in the ecosystem
How is intermediate hypothesis present on rocky shore line
On small boulders there is greater disyrubence so only occupied by the pioneer species Ulva so a lopw biodiversity
On intermediate boulders there are medium levels of disturbence so then most species are present of all algae types so larger biodiversity
On large boulders there is less distrubence so then only the climax community gigartine alage so low birodiversity
How are distrubence and surface area linked together
A larger surface area will correlate to more species however to test if it was SA or distrubence that had effect on biodiversity
Researchers used artifical stable small boulde=rs to see if it is surface area that makes difference to what algae inhabit it
They found on stable small boulders there was more gigartine in a climax community and so proved that disturbence will determien the succession and species richness
What are the 4 disturbence Regimes
A - No disturbence - Only climax community
B - Frequent small scale distrubence - Only pioneer species present
C - Infrequent small scale disturbence - Mix of any algae type
D - Infrequent large scale distrubence - Only pioneer species
C has highest biodiversity calculated by Simpson Index
What is nutrient cycling
This is the way in which nutrients are able to travel through the ecosystem this is because elements cant be destroyed like energy can onoy be transferred in different forms
What is a nutrient pool, flux, source and sink
Pool - The amount of a nutrient that is stored in a part of the ecosystem
Flux = The rate at which these nutrienst move from 1 pool to another pool
Source = A nutrient pool where nutrients are released afaster than they are absorbed so net flux is out the pool
Sink = Where nutrients are absorbed quicker than they are release so net flux in into the pool
What is the phosphorus cycle
Phosphorus is stored in rocks and soil that then will run off into streams and lakes
Here they are stored as inorganic phosphate where they then get absorbed by plants
In plants they are stored as organic phosphate ions where they are consumed by animals or metabolsied by plants
They are then stored as ATP in plants and animals that then die and are decomposed
Here the phosphate is then stored in soil and rocks
What is the Carbon cycle
This cycle is driven by the level of co2 between organsims and the atmosphere
High levels of co2 in the atmosphere and also made durnign respiration and released to atmosphere where then plant take it in for photosynthesis
Humans have added a stage by the death of fossils are then burned as fossil fuels and that will release co2 to the atmosphere
What are the steps of the carbon cycle
Co2 in the atmosphere is taken up by plants for photosynthesis and C held in organinc matter in plants
These plant either then die so then deocomposers will break down the plant matter and release co2 when they carry out respiration
Animals may also eat the plants and C held in animal organic molecules that then either die and are again broken donw by decomposers that release C
Animals and human also undergo respiration that release CO2 to the atmosphere
Dead fossil plants are burned by humans as fossil fule and release co2
What is the Nitrogen cycle
Nitrogen in the atmosphere is large pool as well as in soil
N2 in the atmosphere is rediuced to NH3 that then undego ammonification to make NH4+ that then goes through nitrification to make No3-
Nitrogen fixing bacteria is the onlt organsim that can use atmospheric nitorgen and is often in a symbitoic relation woth plant living in the root nodules
What are the steps of the Nitrogen cycle
Atmospheric nitrogen can go to protein in plant by nitrogn fixing bacteria, the plants are then eaten and excreted by animals so get nitrogenous waste
This waste is stored as ammoni that then form ammonium compounds that are then stored as nitrites in the soil due to nitrifying bacteria and then these work agai n to turn nitrite to nitrate that then use denitrifying bacteria to release N2 to the atmosphere
What is decomposition
This is the breakdown of chemical bonds in organic molecules to release enery, co2, water and inorganic nutrients. This is done by decomposers of all size like the smallest called microflora, to detrivores, 5o mesofauna to then macrofauna then the largest are called megafauna
What factors effect decompostiton rate
Moisture, tenperature, chemical makeup of subsrate and chemical makeup of environment
How does moisture effect decomposition rate
When there is more moisture in an environment there is greater leaf loss in a year where there is much greater rainfall there is greater decomposition of the leaf as less of the biomass remaining in the wet environment
The higher the evapotranspiration will link together the moisture and the temperature will then also mean a greater rate of decomposition as more biomass loss
How does chemical compostion of substrate effect decomposistion
The total amount of carbon will decreased over time independent of where the Carbon is located
Carbon in Protein will lead to much quicker carbon loss compared to carbon in lignin( Wood) that takes much longer for the C to be decomposed Carbon in cellulose takes less time than lignin but more than protein to be decomposed and lost
Can also dependd in species of the tree to determine the rate of decomposition as wood from different trees decompose at different rates depending on the chemical makeup of the species specific leaf and wood
If there is a high lignin content then there is a higher % of original biomass left after time period compared to trees that have lower lignin makeup
How does the envionment compostion effect decomposistion
Depending on the type of rock and also the location of the rock will change the soluble phosphorus in the soil and so effect the decomposition rate
What is mineralisation
This is where organinc material will turn into inorganic matter
The levels of Nitrogen change in litter over time due to leaching where organic N decrease as water soluble compounds lost
Mineralisation where organic N is transformed to inorganic N and then immobilisation where organic N increase as inorganinc N taken up by decomposers
Net mineralsisation = Mineralisation - Immobilsation
Whatr are the feedback loops involved in mineralisation
This is all controlled by feedback loops as where the system is it may fluctuate between high productivity state or low productivity state there are feedback loops for both states – It is a + feedback loop as high or low nutrients lead to + or low rate of the processes until a limit is reached
What is anthropogenic disturbence
This is how huamns disrupt the nutrient cycles and the mineralisation cycles via deforeststion and eutrophication
What is deforestation - anthropogenic disturbence
In area that have human interference there is 10x greater level of where nitrates are washed out of the system via water in the system compared to areas where there is no deforestation and no human interference
What is eutrophication - anthropogenic disturbence
If there is an increase in nutrients such as Phosphorus and Nitrogen as humans pump them into the system, this then lead to increase primary production but this lead to decrease in biodiversity
In normal lake high biodiversity but if greater nutrient lebel as we pump them into lake so then get greater algae bloom that then prevent light getting to plant in the lake so then they die so then less food source for animals so then they die as well so only the algae bloom less