Ecosystems Flashcards
What is an ecosystem?
A distinct, self-supporting system of organisms which interact with each other and with the physical environment. They can be small or large.
What is the definition of an abiotic factor?
A non-biological/ non-living part of an ecosystem.
What is the definition of a biotic factor?
A living part of an ecosystem.
What is an example of an abiotic factor?
Soil
Water
Air
What is an example of a biotic factor?
Plants
Animals
What is the definition of a habitat?
Where specific organisms live.
What is the definition of the population in an ecosystem?
The number of a particular species in an ecosystem at a given time.
What is the definition of the community in an ecosystem?
Populations of different species added together.
What biotic factors may affect an ecosystem?
- Plant material as food
- Number of potential predators and prey
What abiotic factors may affect an ecosystem?
- Purity of water/soil
- Weather/light intensity
- Amount of water - deep/shallow
Why would it be impractical to count every organism in an ecosystem?
- There are too many
- Some may be re-counted or not counted at all
- May be difficult to tell apart different individuals.
What are quadrats?
Metal frames placed on the ground, so organisms within can be counted.
Why must sampling be random?
To avoid bias.
How can sampling be random?
Using dice to determine the X, Y coordinates where you place your quadrat.
How do you sample an area?
Using quadrats and percentage cover.
How do you determine the total population of a particular species in an area?
You sample, and then add up your sampling area to calculate the total.
What is biodiversity?
The variety of life on earth and the essential interdependence of all things.
What is a main feature of a highly biodiverse ecosystem, and what is an example of one?
A large variety of different species, a coral reef.
What do arrows in food chains show?
The flow of energy.
Where does energy in a food chain come from?
The producer creates its own food, using energy it gained from the sun.
How does a producer make its own energy?
Photosynthesis.
What is a trophic level?
A level of feeding (trophic means feeding)
What is a predator?
An animal which eats other animals.
What is prey?
An animal which gets eaten by other animals.
What does a decomposer do, and what is an example of one?
Consumes/ breaks down all organisms.
Fungi or bacteria
What are the different types of consumers?
- Primary Consumer
- Secondary Consumer
- Tertiary Consumer
- Quaternary Consumer (Apex Predator)
What does apex predator mean?
An animal that is a predator, but does not have any predators itself. (Top of the food chain)
Why are food webs better than food chains? (On paper)
Food chains are oversimplified. Food webs show a collection of them, and show more interactions between organisms.
Why are feeding relationship diagrams usually pyramid- shaped?
Energy is lost at each trophic level.
How much energy is lost at each trophic level?
Approximately 90%
Why do most food chains not have more than 5 trophic levels?
Too much energy is lost at each trophic level.
Why is there a loss of energy at each trophic level (in animals)?
- Egestion (feces)
- Excretion (carbon dioxide, sweat, urine)
- Temperature (respiration)
- Movement
- Not all of the organism is eaten ( tail, bones, organs, roots (plants) )
What two types of pyramids are there when depicting food chains?
- Pyramids of numbers
- Pyramids of biomass
What is biomass?
The dry mass (no water)
How can you calculate an organism’s dry mass?
Put it in the oven at 101 degrees celcuis, then keep weighing and re-weighing until it no longer loses any mass.
How can you calculate a species’ biomass?
Mass of living material x number of organisms.
What are carbon atoms needed for in living organisms?
Making carbohydrates, proteins, lipids and DNA.
How do plants and animals obtain their carbon?
Plants from carbon dioxide by photosynthesis, animals from plants by feeding.
Which processes put carbon dioxide into the atmosphere?
Combustion
Respiration
Which processes take carbon dioxide from the atmosphere?
Photosynthesis
Fossilisation
What do nitrifying bacteria do?
Change ammonium into nitrites and then into nitrates.
What do nitrogen fixing bacteria do in the root nodules?
Turn nitrogen gas into ammonium and then plant protein.
What do denitrifying bacteria do?
Turn nitrates into nitrogen gas.
What are nitrogen atoms needed for in living organisms?
Making DNA and proteins.
How do plants and animals obtain their nitrogen?
Plants get it from nitrates in the soil by nitrification (and assimilation) and animals get it from plants by feeding.
Which processes put nitrogen into the soil?
Lightning on nitrogen gas, nitrification, and nitrogen fixation.
Which process takes nitrogen from the soil?
Denitrification
What types of plants contain nitrogen-fixing bacteria in their root nodules?
Legumes
How do the bacteria in the root nodules of legumes benefit?
They get glucose.
How do the legumes with bacteria in their root nodules benefit?
They get ammonia, which can be converted into amino acids. (nitrification can occur)
