Biology unit 19 Flashcards
the sun
The sun is the principal source of energy input to biological systems
Describe the flow of energy
Explain why the transfer of energy from one
trophic level to another is often not efficient
Describe food chain
As showing the transfer of energy from one organism to the next, beginning with a producer
Describe food web
As a network of interconnected food chains and interpret food webs
Describe producer
As an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis
Describe consumer
As an organism that gets its energy by feeding on other organisms
Describe herbivore
As an animal that gets its energy by eating plants
Describe carnivore
as an animal that gets its energy by eating other animals
describe a decomposer
As an organism that gets its energy from dead or waste organic material
improve nutritional qualities. eg ‘golden rice’ contains genes from another plant and a bacterium which make the rice grains produce a chemical that is turned into vitamin A in the human body.
Most of the changes in populations of animals and plants happen as a result of human impact - either by overharvesting of food species or by the introduction of foreign species to a habitat, these can have long-lasting knock-on effects to organisms throughout a food chain or web
Advantages of using a pyramid of biomass instead of a pyramid of numbers
Pyramids of biomass provide a much better idea of the quantity of the plant or animal material at each level of a food chain and therefore are a better way of representing interdependence within the food chain
Describe a trophic level
As the position of an organism in a food chain, food web or ecological pyramid
advantages of using a pyramid of energy than pyramid of numbers or biomass to represent a food chain
- the energy available at each trophic level
- the efficiency of energy transfer at each trophic level
Explain why the transfer of energy from one trophic level to another is often not efficient
as only around 10% of the energy is passed on to the next trophic level, while the other 90% is lost to the environment e.g movement requires energy and respiration - generating heat which is lost from the body to the environment
Why food chains usually have fewer than five trophic levels
because the number of organisms decrease along a food chain because the available energy decreases. The longer the food chain, the more energy is lost. There would not be enough energy left to support a population of fifth consumers at the end.
Why it’s more energy efficient for humans to eat crop plants than livestock that have been feed on crop plants
if humans eat the wheat there is much more energy available to them than if they eat the cows that ate the wheat
This is because energy is lost from the cows, so there is less available to pass on to humans. Therefore, it is more energy efficient within a crop food chain for humans to be the herbivores rather than the carnivores
Describe population
As a group of organisms of one species, living in the same area, at the same time
Describe community
As all of the populations of different species in an ecosystem
Describe ecosystem
As a unit containing the community or organisms and their environment, interacting together
