Unit 4^ Ecology + Environment Flashcards
Habitat
place where organism lives
Population
all organisms of one species in a habitat
Community
Is all the different species in a habitat
Ecosystem
all organisms living in a particular area and all the abiotic conditions they’re exposed to
Biodiversity
the variety of different species of organisms within an ecosystem
Abiotic
Non living
Biotic
Living
What is meant by the word INTERDEPENDENT when describing a food web
That if 1 species changes it affects all the others
Hydroponics
Crops grown with their roots in a solution of mineral ions rather than soil
Producers
Plants which photosynthesise to produce food
Consumers
Animals that eat plants or other animals
Decomposers
Organisms that break down dead material + help to recycle nutrients
Explain how the use of fertilisers contributes to algal bloom
- fertilisers contain minerals like nitrates
- when it rains these leach into waters which causes EUTROPHICATION (elevated levels of nitrates in water)
- which causes ALGAL BLOOM which is a layer of algae which cover the surface of the water which absorb O2 + block sunlight
Explain how the algal bloom causes anaerobic bacteria thrive + aerobic ones to die
- algal bloom is caused by fertilisers which cause elevated levels of nitrates in water = eutrophication
- this algae absorbs o2 + blocks sunlight= many plant die cos of lack of sunlight this increases the dead organic matter which will decompose
- once the nitrate has ran out the algae will also die, also increasing dead organic matter
- the decomposing matter uses o2 + o2 levels drop
- aerobic organisms die + anaerobic thrive cos of lack of O2
Design an experiment to investigate the population size in 2 diff areas
- pick 2 areas
- generate random coordinates + lay out measuring tape on field to form x & y axis
- find coordinates and place Quadrat
- count organisms within Quadrat (the ones ur interested in)
- repeat for each coordinate
- calculate mean = number of organisms : number of Quadrats
- repeat for second field + compare results
What are the limitations of the Quadrat experiment
Sample is representative
Person could still be biased when placing Quadrat
Quadrat counted INACCURATELY
What do the arrows in a good chain represent
Transfer of energy
Why is not all the energy in a trophic level passed on to the next trophic level (give 3 reasons)
- some parts of food not eaten or INDIGESTIBLE (bone)
- used up for RESPIRATION
- transferred to surroundings by HEAT
Why do we need biodiversity
High biodiversity makes sure ecosystems r stable cos organisms depend on each other for
- shelter + food
- physical environment (pH of soil)
What causes the environment to change all the time
Abiotic + biotic factors
Give examples of ABIOTIC factors that change an environment
• environmental condits
- pH of soil
- light intensity
•toxic chemicals:
- pesticides (cause bioaccumulation)
- fertilisers (cause eutrophication)
Give examples of BIOTIC factors that change the environment
🍐 availability of food
🦈number of predators
🐉competition
What do pyramids of biomass show and what shape must they always have
Always have pyramid shape
Biomass = population size x mass of individual
pyramids of biomass show the mass of living material at each stage of the food chain
What do food webs show
Food webs show how food chains r linked
INTERDEPENDENT = if 1 species changes it effect all the others
Describe the carbon cycle (5 marks)
🌱 plants use carbon from co2 to make carbohydrates, lipids + proteins
🐄 animals eat plants which passes carbon along food chains
🔥respiration by living things releases co2 back into the air
🦴 animals + plants die = go into soil where they’re broken down by ..
💀DECOMPOSERS which use enzymes to break down the dead material using it for respiration (co2 released)
✈️fossil fuels are burnt by humans =combustion releases co2
What percentage of energy available becomes biomass?
Only 10% of the total energy available becomes biomass
