B7 - Ecology Flashcards
What does population mean?
All the members of one species living in a habitat.
What is a community?
The populations of different species living in a habitat.
What is a habitat?
The place where an organism lives.
What is an abiotic factor?
Non-living factors of the environment e.g. temperature.
What is a biotic factor?
Living factors of the environment e.g. food.
What is an ecosystem?
The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.
What 6 things do living things fight over?
Food
Sunlight
Water
Mate
Space
Shelter
What are stable communities?
When the species and environmental factors are in balance so population sizes remain roughly constant.
What are 4 biotic factors?
- Food availability
- Disease causing microorganisms
- Predators
- Competition between organisms
What are 10 abiotic factors?
Water
Space
Moisture levels
Nutrients in the soil
CO2 levels
Soil pH
Oxygen level
Wind intensity
Temperature
Light intensity
What are the 4 trophic levels in the food chains?
Producer - plantain
Primary consumer - grasshopper
Secondary consumer - frog
Tertiary consumer - fox
What is a herbivore?
An animal that eats plants.
What is a carnivore?
An animal that eats meat.
What are trophic levels?
The stages in a food chain.
What is trophic level 1?
Producers - they make their own food through photosynthesis.
What is trophic level 2?
Primary consumer - herbivores which eat producers.
What is trophic level 3?
Secondary consumer - carnivores that eat herbivores.
What is trophic level 4?
Tertiary consumers - carnivores that eat carnivores.
What is an apex predator?
A carnivore with no predators.
How do decomposers break down dead matter?
They release enzymes which catalyse the breakdown of dead material into smaller molecules.
The small molecules then diffuse into the microorganisms.
What is biomass?
The dry mass of a living organism.
Why is dry mass used for biomass?
Because the wet mass varies, because the volume of water in an organism varies.
How do you calculate the efficiency of biomass transfer?
efficiency = (energy transferred / total energy available) x 100
What percentage of the incident energy from light do producers transfer?
1%
What percentage of the biomass from one trophic level is transferred to the level above it in feeding?
Approximately 10%
Why are biomass transfers not 100% efficient?
Energy is lost through:
- excretion and egestion
- respiration
- the production of inedible shells and bones
How does the efficiency of the transfers affect the number of trophic levels in a biomass pyramid?
The less efficient the transfers the fewer trophic levels and the fewer organisms in the higher trophic levels.
What is a biomass pyramid?
A pyramid that shows the total dry mass of organisms at each trophic level.
What is a pyramid of numbers?
It shows the number of organisms at each trophic level.
Why are pyramids of numbers not as widely used as pyramids of biomass?
They don’t take the size and mass of organisms into account.
Why are pyramids of biomass useful?
Because they depict how much food is available for the next level of the food chain.
What controls the amount of carbon in the atmosphere?
The carbon cycle.
What 2 processes take carbon dioxide from the atmosphere?
- Photosynthesis by plants
- Dissolving in the ocean
What 2 processes release carbon dioxide to the atmosphere?
- Respiration by plants, animals and microbes.
- Combustion
What human activities has led to a higher proportion of carbon dioxide in the earths atmosphere?
Burning fossil fuels as energy sources.
Deforestation, meaning there is less photosynthesis that removes carbon dioxide from the air.
What happens when organisms die or produce waste?
Dead matter and waste is decomposed by decomposers (bacteria and fungi) and detrivores.
What are detritivores?
Consumers such as woodlice and worms.
State the levels of organisation in an ecosystem.
Individual, population, community, ecosystem.
What is intraspecific competition?
Competition within a species.
What is interspecific competition?
Competition between different species.
What is interdependence?
Different species in an ecosystem depend on each other. If one species is removed, the whole community breaks down.
What is a stable community?
A community in which all the biotic factors and abiotic factors are stable so the population sizes remain relatively constant.
Why might light intensity affect an ecosystem?
Different species of plants have different optimum light intensities for growth.
Why does temperature affect an ecosystem?
Different species of plant and animals may have different optimum temperatures for growth and survival.
What plant has it’s appearance altered by soil pH?
Hydrangea.
How does soil pH affect an ecosystem?
Certain plants may grow better in either an alkaline or acidic soil.
How does moisture levels affect an ecosystem?
Many plants cannot survive in waterlogged soil as their roots cannot respire.
Certain plants are adapted to high moisture levels.
How does moisture levels affect an ecosystem?
Plants seeds are more likely to germinate in locations with a lower wind intensity, which may attract animals that depend on the plant to live nearby.
How does soil mineral content affect an ecosystem?
Most plants require a high level of soil minerals to grow well.
Give an example of the type of plants that have adapted to low soil mineral content.
Carnivorous plants catch insects to make up for the low level of soil mineral content.
How does carbon dioxide concentration affect an ecosystem?
Higher carbon dioxide concentration leads to more plant growth.
How does oxygen concentration affect an ecosystem?
Aquatic animals cannot survive in areas with a low oxygen concentration.
What are adaptations?
Features that enable organisms to survive in their living environment.
What are organisms living in extreme environments called?
Extremophiles.
Give 3 examples of extreme living conditions.
High temperature.
High pressure.
High salt concentration.
State an example where extremophile bacteria can be found.
In deep sea vents.
What are 3 types of adaptations?
Structural - shape or colour.
Behavioural - ways an organism behaves.
Functional - processes that take place in an organisms body.
What are thermophiles?
Organisms that live at high temperatures.