bio 20
ecology
the branch of biology that deals with the study of the interactions among organisms with their environment
ecologists
scientists who study ecology
ecosystems
a physical environment and all the living things within it
habitat
each type of living thing in an ecosystem has a place where it lives
niche
the combination of the job an organism does and the place in which it lives
producers
trap energy in sunlight and produce their own food
consumers
cannot make their own food and must obtain it from producers or other consumers
decomposers
break down dead plant and animal remains and convert them into substances that can be reused
what would happen if all decomposers were destroyed
excess of waste, nutrients wouldnt be put back which would slow growth of plants and animals
trophic level
each step on a food chain/web
detritovore
organisms that eat dead material and animal waste
difference between decomposers and detritivores
While decomposers break down dead organic materials, detritivores eat dead organisms and waste
producer example
wild rice
primary consumer example
minnow (second trophic level)
secondary consumer example
northern pike (fish)
tertiary consumer example
eagle
decomposer example
bacteria fungi
detritivore example
earthworms, crab
food chains and web
A food chain is a linear sequence of organisms that shows their feeding relationships. A food web is all of the food chains in an ecosystem.
primary consumer
feed directly on plants
secondary consumers and tertiary consumers
secondary consumers feed on primary consumers, tertiary consumers feed on secondary consumers
scavengers
carnivores that feed on dead animals
acid precipitation
precipitation that contains more acid than normal
biodiversity
the large variety of organisms that live on this earth
carbon cycle
the flow of carbon through an ecosystem, from living organisms to the atmosphere and back again
cellular respiration
the chemical process by which glucose reacts with oxygen to produce energy, carbon dioxide, and water
closed system
an environment that substances cannot enter or leave
denitrification
the process by which nitrates are changed into nitrogen gas
nutrient cycle
the path of a nutrient through an ecosystem
nutrients
any substance that a living organism consumes and uses for growth, repair, and funciton
photosynthesis
the chemical process, occuring in green plants, by which carbon dioxide and water combine in the presence of sunlight to make glucose sugar and oxygen for the atmosphere
sustainabilitiy
the ablility of the present generation to meet its needs to sustain life without affecting the ability of future generations to meet their needs
sustainable development
using renewable resources in a way that does not harm the nevironment but increases the standard of living for the human population
where does cellular respiration occur
in both plants and animals, in the mitochondrion
what is the mitochondrion made up of
folds called cristae, which is where cellular respiration occurs
cellular respiration equation
C - H20 + O2 = CO2 + H2O + Chemical energy (ATP)
EXPANDED
C6H12O6 + 6O2 = 6H2O + 6CO2 + ATP
what does photosynthesis mean
putting together with light.
how does photosynthesis work
plants capture energy from the sun through pigments called chlorophyll. chlorophyll is found in organelless called chloroplasts
photosynthesis equation
light energy + CO2 + H2O = C - H2O + O2
EXPANDED
light energy + 6CO2 + 6H20 = C6H12O6 + 6O2
carbon cyle diagram
top- mitochnodrion
left- carbohydarate oxygen
right- energy carbon dioxide water
bottom- chloroplast
inside top- cellular respiration
inside bottom- photosynthesis
what can a carbohydrate be
sugar or starch
what do producers do in photosynthesis
take in carbon dioxide from atmosphere, carbon atoms are transferred to carbohydrates
what is glucose
Glucose is the type of sugar that our bodies use for fuel
what do aerobic organisms do in respiration
break down carbohydrates, release carbon dooxide into atmosphere and provide energy
what do decomposers do during cellular respiration
break down plant and animal materials, carbon dioxide is released into atmsophere
algal bloom
population explosion of algae in water bc of an increase in nutrients
eutrophication
a water system that has had to many nutrients added to it, which causes an increase in bacterial growth that uses up the oxygen, animals that require higher o2 levels die
nitrogen in ecosystems
biogeochemical cycles
bio- biotic components must reproduce
geo- abiotic components must be recycled
chemical- water cycle, carbon cycle, nitrogen cycle
abiotic
the nitrogen cycle serves two purposes
helps keep environment clean by breaking down dead organic matter, and replenishes the supply of nitogen available in ecosystem
why do we need nitrogen
it is a necessary component of all proteins
it is necessary for the formation of nucleic acids
how much nitrogen gas is in our atmosphere
80%
we cannot break the bond in N2
atmospheric nitrogen has a strong covalent bond yhay takes a lot of energy to break. the only rhings thay can break teh bond are lightning and volcanic activity. it is a triple bond
bacteria and nitrogen
The majority of the nitrogen that is used by living things is made available by bacteria. Nitrogen can only be used after this strong covalent bond is broken.
the nitrogen cycle steps
1. nitrogen fixation
2. decomposition
3. ammonification
4. nitrification
5. assimilation
6. denitrification
nitrogen fixation
unusable nitrogen-usable nitrogen
n2-ammonia nh3
soil bacteria can reduce atmospheric n2 to nh3. they can be free in soil, or live in roots of some legumes
legumes
peas beans alfalfa clover have bacteria
decomposition
freeing up usable nitrogen- bacteria and fungi break down dead organic matter like waste, fallen leaves, dead plants and animals
ammonification
fixing what comes from decomposition- bacteria and fungi turn the nitrogenous end products of decomposition into ammonia (NH3). This is the same result as in nitrogen fixation, but in this step, the nitrogen comes from an organic compound and there is no high energy bond to break.
nitrification
making different forms of usable
nitrogen- certain bacteria are able to oxidize ammonia (NH3) to nitrite (NO2-), and then to nitrate (NO3-). In this way, the bacteria gain the energy that they need, and give off nitrate (NO3-) as a waste product.
assimilation
• Plant roots absorb ammonia (NH3) and nitrate (NO3-), and use them to build amino acids, proteins, and nucleic acids.
• Animals eat plants and assimilate their nitrogen into more organic molecules
denitrification
usable nitrogen-unusable nitrogen
Some bacteria obtain their oxygen from nitrate (NO2), and release nitrogen gas (N2) and nitrous oxide (NO) into the atmosphere a waste products.
are all members of a food web equal in abadunce and effects?
no, not all members are equal in abundance bc there are less moving up trophic levels, and some have effects disproportionate to their abundance
is every member of a food web is the prey of another member of the food web?
The apex predators are not prey to any member of the food wel
what is a keystone species
keeps the ecosystem together, critical to the diversity and stabilty
green world hypothesis
The green world hypothesis shows that predators limit the
# of herbivores which is from up-down
if a food chain goes grass -> grasshoppers -> mice -> snakes, what would happen to the grass?
I would expect the number of grass to decrease because snakes will make the mouse population go down, making the grasshoppers increase, eating more grass
pyramids
illustrate different feeding relationships, show Visual comparisons amona organisms at different trophic levels generally indicate relative "numbers" of species needed to populate an area successfully
pyramid of numbers
(HOW MANY, DRAWN AS BLOCKS) show numbers at each trophic level, generally large number of producers, fewer + fewer consumers moving up, but, sometimes they can be inverted.
pyramid of biomass
(HOW MUCH, DRAWN AS BLOCKS) improvement: take into account the size or mass of the organisms
pyramid of energy flow
(NOT BLOCKS) shows the amount of nutrient energy at each trophic level, must be upright, on average, only 10% of one trophic level is available to the next level.
biological magnification
the process by which substances eaten by organisms get passed on through the food chain in greater concentrations toward the top of the food chain; also called "bioaccumulation"
biomass
the "weight" of living things in a community or population, divided by the area
carrying capacity
the maximum number of organisms that can survive in an area, living off the available resources
what is a typical population growth curve
s shaped
first region of s curve
region of slow population growth, Only a small number of organisms are sexually mature and able to reproduce.
• The organisms may be adjusting to a new environment.
second region of s curve
region of rapid population growth: • Many organisms have reached sexual maturity. They are able to reproduce.
• The organisms have adjusted to the conditions around them. They have found food, shelter, and water for survival.
third region of s curve
region of steady population growth: • The carrying capacity is reached. Population growth becomes constant.
• The number of deaths equals the number of births.
what are factors that could limit a populations growth?
lack of nutrients, build up of waste, disease, no sunlight
what does grow exponentially mean?
IT MEANS THAT THE POPULATION'S RATE OF INCREASE IS CONSTANT. it is an increasing slope
what does a straighter exponential graph mean?
growing more rapidly, a more slanted one means slower
what does exponential growth have
a fixed/constant doubling time
what happens when it hits carrying capacity
IT WILL SLOW AS IT APPROACHES THE CARRYING CAPACITY AND LEVEL OFF, REACHING A HAPPY ACCOMMODATION WITH THE ENVIRONMENT. THIS GIVES AN S CURVE.
what is a j curve
A PERIOD OF RAPID POPULATION INCREASE FOLLOWED BY COLLAPSE, after depleting the available resources, it leaves a remnant of the og population at a new cc
what usually happens when a population is small compared to cc
IT GROWS MORE OR LESS RAPIDLY, DEPENDING ON ITS INTRINSIC RATE (species specific) OF REPRODUCTION. WHAT HAPPENS NEXT DEPENDS ON MANY FACTORS.
what is a density dependent factor
increase in significance as a population grows. ex) overcrowding
what is a density independent factor
can limit a population regardless of size ex) natural disasters
interspecific competition
When two organisms from different species are after the same resources and food
intraspecific competition
When two organisms from the same species are after the same resources and food
population density
The number of organisms that live in a given area
what happened in the pesticide example?
the ddt concentration built up through the food chain, demonstrating biological magnification
substances that undergo biological magnification have two properties that make them dangerous:
not biodegradable- decomposers cant break them down into harmless substances
fat soluble- can accumulate in the body tissues of animals