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