Chapter #18 - Organisms And Their Enviornment Flashcards
Ecology
the study of organisms in their environment.
Do organisms live in isolation of each other?
Organisms do not live in isolation of each other. They live in an environment with many other organisms.
Habitat
The place where an organism lives
Population
A group of organisms of the same species, living in the same area at the same time.
Community
All of the populations of all of the different species in an ecosystem.
Ecosystem
A unit containing all of the organisms in a community and their environment, interacting together.
Niche
the role of an organism in its natural environment. The wayinwhich it interacts with other organisms and with the non-living partsofthe environment.
What do organisms do in an ecosystem?
In an ecosystem, each organism has a role.
Where does all the energy in an ecosystem originate from?
- The sun
- Sunlight energy is captured by plants and turned into glucose/starch/otherbiological molecules
- Animals get their energy by eating plants
Food chain
A diagram showing the flow of energy from one organism to the next, starting with a producer
Producer
An organism that makes its own organic nutrients (usually using energy from sunlight, through photosynthesis).
Consumer
An organism that gets its nutrients by feeding on other organisms.
Primary – secondary – tertiary – quaternary… etc
Food web
a network of interconnected food chains.
Which way do the arrows point in a food web?
In the direction of the energy flow
How does energy get transferred between trophic levels?
About 10% of the previous trphic level’s energy gets transferred.
How does biomass change across trophic levels?
There is less biomass the higher the tropic level. This is because about 10% of the prevous trophic level’s energy is passed on only.
Trophic level
Position of an organism in a food chain/web or pyramid.
Herbivore
an animal that gets its energy by eating other plants.
Carnivore
an animal that gets its energy by eating other animals.
Decomposer
an organism that gets its energy from dead or waste organic material.
How is energy lost as it is passes through a food web?
- Heat loss from respiration
- Not all parts of the organism are eaten e.g. roots and bones not being eaten
- Not all parts of the organism being eaten is absorbed. When an animal eats another,its digestiveenzymes break downmost of the nutrients,but not all. Some are not digested or absorbed and are just removed as faeces. (Faeces contain energy, but it is lost from that food web.
- Not all organisms are eaten so they may die and they are decomposed.
Pyramid of numbers
a graph showing the total number of individual organisms at each level in the food chain of an ecosystem.
What happens to the number of organisms at different positions in a food chain?
There are usually more plants than animals and more herbivores than carnivores in a food chain.
How can we represent the number of organisms at different positions in a food chain?
We can represent the number of organisms using a pyramid of numbers.