Communities and ecosystems Flashcards
Define an ecosystem?
A community and the physical environment it interacts with.
Define a community?
A group of populations living and interacting with each other in a common habitat.
How can you describe respiration and photosynthesis?
Processes with inputs, outputs and transformations of energy and matter.
What is respiration?
The conversion of organic matter into carbon dioxide and water in all living organisms, releasing energy.
Word equation for aerobic respiration?
Glucose + Oxygen to Carbon Dioxide and Water
How do entropy levels change during respiration?
Energy is dissipated as heat, increasing the entropy in the ecosystem while the organism manages to maintain a relatively low entropy.
Word equation for photosynthesis?
Carbon Dioxide + Water to Glucose + Oxygen
What is a trophic level?
The position that an organism occupies in a food chain.
What are producers?
They are autotrophs. They produce their own food using photosynthesis.
Where are producers in a food chain?
They form the first trophic level.
Do any producers not use photosynthesis?
Yes, chemosynthetic organisms can produce food without sunlight.
What is bioaccumulation?
The build up of non-biodegradable pollutants within an organism or trophic level because they cannot be broken down.
What is biomagnification?
The increase in concentration of non-biodegradable pollutants along a food chain.
What is an example of biomagnification?
DDT and mercury.
How do you determine if something is a living thing?
If it carries out the following processes: Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition
What are the two types of respiration>?
Aerobic, anaerobic
Chemical equation for aerobic respiration:
C6H12O6 + 6O2 to 6CO2 + 6H20 + energy
What is the compensation point of a plant?
When all the carbon dioxide that a plant produces in respiration is used up in photosynthesis and there is no net release of carbon dioxide or oxygen (equilibrium).
How is the biomass changing at the compensation point of a plant?
It’s not. The plant is neither adding biomass or using it.
What is a food chain?
The flow of energy from one organism to the next.
Name all stages of a food chain
Primary Producers Primary Consumers Secondary Consumers Tertiary Consumers Decomposers Detritivors
How do decomposers obtain their energy?
What is an example of a decomposer?
From dead organisms by secreting extracellular enzymes that break down the organic matter.
E.g. a funghi
How to detritivors obtain their energy?
What is the difference between detritivors and decomposers?
What is an example of a detritivor?
From decomposing organic material. i.e. feces or dead skin.
Decomposers are on a milliscopic level whereas detritivors are larger animals, such as a millipede.
What is a food web?
A complex relationship of interrelated food chains.
Example of a food chain:
In the African savannah: Acacias Impala Leopard Lion
What are the positives of food chains in general?
They allow easy examination of energy transfers and losses. They give an idea of what feeds on what and what organisms can exist at the different trophic levels. They help to demonstrate that ecosystems are systems that are in balance,
Where does the energy go in a food chain?
Most of it is lost as heat because of the second law of thermodynamics. More islost because herbivores destroy more plant material than they eat, by trampling on it or because they can’t eat it so they reject it. Some material is not digested and some dies and decomposes before eaten.
What is the second law of thermodynamics?
It states that energy is degraded to a lower quality and finally to heat.
