Topic 7: Ecology Flashcards
Define ‘habitat’
The place where an organism lives
Define ‘population’
All of the organisms of one species living in a habitat
Define ‘community’
The populations of different species living in a habitat
Define ‘abiotic factors’
Non-living factors of the environment
Define ‘biotic factors’
Living factors of the environment
Define ‘ecosystem’
The interaction of a community of living organisms with the non-living parts of the environment
What do plants compete for? [4]
- Light
- Space
- Water
- Mineral ions in soil
What do animals compete for? [4]
- Space (territory)
- Food
- Water
- Mates
What are some abiotic factors? [4]
- Light intensity
- Temperature
- Carbon dioxide level (plants)
- Soil pH
Explain how a decrease in light intensity (abiotic factor) would affect a plant population [3]
- Decrease the rate of photosynthesis
- Affect the plant growth
- Cause a decrease in the population size
Explain how a decrease in mineral content (abiotic factor) would affect a plant population [3]
- Cause nutrient deficiencies
- Affect the plant growth
- Cause a decrease in the population size
What are some biotic factors? [4]
- New predators arriving
- Competition
- New pathogens
- Availability of food
What is a structural adaptation?
Features of an organism’s body structure
Examples of structural adaptations [3]
- Arctic foxes have white fur
- Whales have thick blubber
- Camels have a thin layer of fat
What is a behavioural adaptation?
Ways that an organism behaves
Examples of behavioural adaptations [2]
- Birds migrate
- Penguins ‘huddle’ together
What is a functional adaptation?
Things that go on inside an organism’s body (related to reproduction and metabolism)
Examples of functional adaptations [2]
- Desert animals produce little sweat to conserve water
- Bears hibernate in winter. They lower their metabolism which conserves energy, so they don’t have to hunt when there’s not much food about
What is the name for microorganisms that can live in extreme conditions?
Extremophiles
What types of conditions can extremophiles live in? [3]
- High temperatures
- High salt concentrations
- High pressures
What does a food chain show?
What eats what in an ecosystem
What happens to energy as it passed along a food chain?
Most of it is lost
What does abundance refer to?
How many organisms there are
What does distribution refer to?
Where the organisms are
What happens in the process of sampling? [2]
- Only a subset of a population is measured
- Use it to make predictions about the whole population
What are quadrats used to measure? (abundance or distribution)
Abundance
What are transects used to measure? (abundance or distribution)
Distribution
Describe the stages of the water cycle [4]
- Energy from the sun makes water evaporate from the land, sea and plants (transpiration)
- The water vapour rises, cools and condenses to form clouds
- Water falls from the clouds as precipitation back into the land or sea
- Plants then abosord some of this water
Describe the stages of the carbon cycle [6]
- CO₂ is removed from the atmosphere by green algae and plants during photosynthesis
- When plants and algae respire, some carbon is returned to the atmopshere as CO₂
- When plants and animals are eaten, some carbon becomes part of their fats and proteins
- When the animals respire, some carbon is returned to the atmosphere as CO₂
- When plants, algae and animals die, other animals and microorganisms feed on their remains
- When these organisms respire, CO₂ is returned to the atmosphere
Define ‘decomposition’
Process by which dead, organic matter is broken down into simpler organic or inorganic susbstances
What is decomposition essential for?
The recycling of elements through an ecosystem
What 2 groups of organisms is decomposition carried out by?
- Detritus feeders
- Decomposers
What are detritus feeders?
Small animals like worms or woodlice
Examples of decomposers [2]
- Fungi
- Bacteria
How does increased oxygen affect the rate of decomposition? [3]
- More aerobic respiration
- More energy available
- Faster growth and decomposition
How does increased temperature affect the rate of decomposition? [4]
- Particles have more kinetic energy
- Enzymes are closer to their optimum pH
- Higher rate of reactions
- Rate of decomposition increases
How does increased water affect the rate of decomposition? [2]
- Decomposers need water to survive
- Rate of decomposition increases in moist conditions
What is compost?
Decomposed organic matter
What is compost used for?
Used as a natural fertiliser for crops and garden plants
What gas does anaerobic decay produce?
Methane gas
How can the methane gas produced by anaerobic decay be harnessed?
Biogas generators can use methane gas to produce fuel
Once the gas has been removed from a biogas generator, what is the sludgy material used for an why? [2]
- Used as fertiliser
- Has high levels of useful minerals
Define ‘biodiversity’
Variety of different species of organisms on Earth, or within an ecosystem
Why is high biodiversity important? [2]
- It ensures the stability of ecosystems by reducing the dependance of one species on another
- Future of the human species relies on high levels of biodiversity (e.g. pollinators for crops)
How can pollution occur in the water? [2]
- Sewage and toxic chemicals from industry can get into water sources
- Chemicals used on land can be washed into water sources
How can pollution occur on land?
Lots of household waste ends up in landfill sites
How can pollution occur in the air?
Smoke and acidic gases can pollute the air
What is the consequence of pollution?
Kills plants and animals, which reduces biodiversity
How can wild populations of endangered species be preserved by breeding programmes? [2]
- Animals are bred in captivity to make sure the species survives if it dies out in the wild
- Individuals can sometimes be released into the wild to boost or re-establish a population
How could the reintroduction of hedgerows and field margins increase biodiversity? [2]
- Provides a habitat for a wider variety of organisms to grow
- This increases biodiversity
What are some problems with trying to maintain biodiversity? [3]
- Costs money
- Comes at a cost to people’s livelihood
- Reduces our food security
Explain how global warming could lead to the loss of low-lying habitats [3]
- Global warming causes higher temperatures, which causes ice to melt and seawater to expand
- This causes the sea level to rise
- This could lead to flooding of low-lying land and therefore the loss of habitats
Suggest why deforestation can result in higher CO₂ concentration in the atmosphere [3]
- Trees ‘lock up’ some of the carbon that they absorb during photosynthesis
- So if lots of trees are removed, less carbon will be locked up from the atmosphere
- If the land is cleared by burning the trees, this means that lots of carbon dioxide is released
Why are peat bogs often drained? [3]
- Area can be used as farmland
- Used as fuel
- Used for compost
What happens when peat is drained or burned? [2]
- Carbon dioxide is released
- Destroys the habitats of the animals and plants living there - reduces biodiversity
Explain how decomposers break down dead material in an environment
They secrete enzymes that break down the dead material into small soluble food molecules
On average, how much energy is lost at every level in a food chain?
10%
Why is biomass lost between trophic levels? [2]
- Not all of the ingested material is absorbed - some is lost as faeces
- Some absorbed material is lost as waste - urea in urine
How do you calculate the efficiency of biomass transfer?
(biomass transferred to the next level/biomass available at the previous level) x 100
How can fishing be made sustainable? [2]
- Fishing quotas
- Increasing net size
How do fishing quotas make fishing sustainable? [2]
- Limits the number of fish that can be caught in an area
- Prevents certain species from being overfished
How does increasing net size make fishing sustainable? [2]
- Allows younger fish to escape
- Allows them to reach breeding age so populations will not decline
What are some factors which affect food security? [4]
- Rising population
- Diets changing
- New pests and pathogens
- Changing environment
Explain how food production from livestock farming can be made more efficient [4]
- The movement of livestock can be restricted
- Or they can be kept in a temperature-controlled environment
- This means that they use less energy moving about and controlling their own body temp
- More energy is available for growth
