Energy Transfers in and between Organisms - Energy and Ecosystems Flashcards
What is an ecosystem?
A biological community of interacting organisms and their physical environment.
Why do organisms need sunlight?
The organisms found in any ecosystem rely on a source of energy to carry out all their activities. The ultimate source of this energy for almost all organisms is sunlight, which is conserved as chemical energy by plants.
What do most plants use sunlight for?
Most plants use sunlight in making organic compounds from carbon dioxide in the air or water that surrounds them. These organic compounds include sugars.
What are the organic compounds produced by plants used for?
These organic compounds include sugars, most of which are used by the plants as respiratory substrates.
The remainder are used to make other groups of biological molecules. These biological molecules form the biomass of plants that is the means by which energy is passed between other organisms.
What three groups can organisms be divided into according to how they obtain their energy and nutrients?
- producers
- consumers
- saprobionts
What are producers?
Producers are photosynthetic organisms that manufacture organic substances using light energy, water, carbon dioxide, and mineral ions.
What are consumers?
Consumers are organisms that obtain their energy by feeding on other organisms rather than using the energy of sunlight directly. Animals are consumers.
Secondary and tertiary consumers are usually predators but they may also be scavengers or parasites.
What are primary consumers?
Those that directly eat producers (green plants), because they are the first in the chain of consumers.
What are secondary consumers?
Those that eat primary consumers.
What are tertiary consumers?
Those that eat secondary consumers.
What are saprobionts?
Saprobionts (decomposers) are a group of organisms that break down the complex materials in dead organisms into simple ones.
In doing so, they release valuable minerals and elements in a form that can be absorbed by plants and so contribute to recycling. The majority of this work is carried out by fungi and bacteria.
What is a herbivore?
An animal that eats plants (producers) and is therefore a primary consumer.
What is a carnivore?
An animal that eats animals and may therefore be a secondary or a tertiary consumer.
What is an omnivore?
An animal that eats both plants and animals is therefore a primary consumer and also a secondary or a tertiary consumer.
What is a food chain?
A food chain describes a feeding relationship in which the producers are eaten by primary consumers. These in turn are eaten by secondary consumers, which are then eaten by tertiary consumers.
In a long food chain, the tertiary consumers may in turn be eaten by quaternary consumers.
