Ecology and Evolution Flashcards
Define species.
a group of organisms that can interbreed and produce fertile offspring.
Define habitat.
the environment in which a species normally lives or the location of a living organism.
Define population.
a group of organisms of one species that live in the same area at the same time.
Define community.
a group of all of the living organisms that live in the same area, interacting with each other
Define ecosystem.
a community and its abiotic environment.
Define ecology.
the study of relationships between living organisms and between organisms and their environment.
What is an autotroph?
Autotrophs are organisms that synthesize their organic molecules from simple inorganic substances.
What is an heterotroph?
Heterotrophs are organisms that obtain organic molecules from other organisms.
What are consumers?
an organism that ingests other organic matter that is living or recently killed.
What are detritivores?
an organism that ingests non-living organic matter.
What are saprotrophs?
an organism that lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion.
What is a food chain?
A food chain shows the linear feeding relationships between species in a community
The arrows represent the transfer of energy and matter as one organism is eaten by another (arrows point in the direction of energy flow)
The first organism in the sequence is the producer, followed by consumers (1°, 2°, 3°, etc.)
Give three examples of food chains.
!!!
Define food web.
A food web is a diagram that shows how food chains are linked together into more complex feeding relationships within a community
There can be more than one producer in a food web, and consumers can occupy multiple positions (trophic levels)
What is the initial energy source for all communities?
Light
Define trophic level.
the trophic level of an organism is its position in the food chain. Producers, primary consumers, secondary consumers and tertiary consumers are examples of trophic levels.
Explain the energy flow in a food chain.
Energy flows from producers to primary consumers, to secondary consumers, to tertiary consumers…
Energy is lost between trophic levels in the form of heat through cell respiration, faeces, tissue loss and death.
Some of this lost energy is used by detritivores and saprotrophs. These in turn also lose energy in the form of heat through cell respiration.
How efficient are energy transfers?
Never 100% efficient
~10% efficient
Explain reasons for the shape of pyramids of energy.
Pyramids of energy will never appear inverted as some of the energy stored in one source is always lost when transferred to the next source
Each level of the pyramid of energy should be approximately one tenth the size of the level preceding it, as energy transformations are ~10% efficient
Explain how energy and nutrients enter, move through, and exit a food chain in an ecosystem.
Energy enters from sunlight which is captured by chloroplasts in plants, and other producers. Energy flows through the trophic levels, only about 10% of the energy is passed on. Heat energy is lost through cell respiration, and is lost from the food chain. Energy is lost due to material that is excreted, this energy passes to decomposers in dead organic matter.
Nutrients are recycled within an ecosystem.Nutrients are absorbed from the soil by producers, they move through the food chain by the digestion of other organisms. The nutrients are then recycled from the decomposition of dead organisms.
What recycles nutrients?
Saprotrophic bacteria and fungi (decomposers) recycle nutrients.
Draw and label a diagram of the carbon cycle to show the processes involved.
Include:
plants taking in CO2 in photosynthesis;
animals eating plants;
animals/plants giving off CO2 by cell respiration;
decomposers/microorganisms giving off CO2 by cell respiration;
fossilization of animal parts, causing them to store carbon as fossil fuels;
factories/cars giving off CO2 through combustion of fossil fuels.
