Ecology Flashcards
ecology
the study of relationships of living things with each other and with their physical environment
biosphere
thin layer of life on the earth
ecosystem
regions within the biosphere
made up of both living (biotic) and nonliving (abiotic) component
community
the living part of an ecosystem
population
all the members of a particular organism in a community
e.g. all the corals in a coral reef
individual
a single organism
producers
photosynthetic organisms
plants, photosynthetic bacteria, and algae
consumers
eat producers or each other
protozoans and animals
decomposers
break down dead producers and consumers
fungi and bacteria
food chain
series of steps by which energy flows through an ecosystem
who eats who?
producer –> primary consumer (herbivore) –> secondary consumer (carnivore) –> tertiary consumer –> quaternary consumer
food web
a group of interconnected food chains
the way it is in the real world
trophic level
what level are you at in the food chain?
transfer of energy from level to level is insufficient (only ~10% gets passed on)
number of organisms decreases from level to level
there can only be a small number of high level consumers b/c it takes so many organisms in lower levels to support them
lots of producers, very little quaternary consumers
ecological pyriamid
graphical representation of the concept of trophic levels
displays number of organisms or amount of energy at each level (decreases as you go up)
bioaccumulation
fat-soluble toxins are not excreted well and so build up in the tissues more and more in higher tropic levels
top carnivores have the highest levels of all, they have accumulated toxin from all levels below them
nutrient cycles
energy is the only thing that is put into an ecosystem
carbon cycle
consumers produce CO2, producers use CO2
decomposers release C trapped in dead organisms back into the cycle as CO2
nitrogen cycle
major component of the atmosphere
found in various biomolecules
soil bacteria convert nitrogenous waste products into forms that plants can use
nitrogen fixation
some bacteria have the ability to convert atmospheric N2 into a form that is usable by plants
terrestrial ecosystems (biomes)
temperature and rainfall influence the distribution
ecosystems occur in bands on distance from the equator (tundra is furthest north)
tropical rain forests-most productive and diverse
wetlands-areas of land covered by water, highly productive
aquatic ecosystems
include fresh and salt water (marine)
coral reefs are most productive and diverse marine ecosystem
littoral zone
where land and water come together
many organisms live there
benthic zone
bottom
bottom-dwelling organisms
pelagic zone
deep open ocean
few organisms live there
symbiosis
2 organisms living together in some sort of relationship
mutualism
both benefit
commensalism
one benefits, one is not affected
parasitism
one benefits, the other is harmed
predator-prey
one feeds on another
ecological niches
the role a particular organism plays in a community
its lifestyle
keystone species
if removed from an ecosystem, has a significant negative impact on the remaining members
natural selection
survival of the fittest
all organisms live under selection pressure-something that might kill you or make it less likely that you will reproduce
the organism that adapts best to or survives the selection pressures will be the most successful
speciation
the development of new species
usually dues to natural selection
species
a group of organisms that can breed with each other, but not members of any other group
new species arise from a previous species over a long period of time
subspecies
geographically separated and different looking members of a species which can interbreed
