Ecolodgy Flashcards
What is an ecosystem
ecosystem is the interaction of a community with non-living (abiotic) parts of the environment. Organisms are adapted to live in the conditions of their environment.
What do organisms compete for
• There can be competition within a species or between different species.
Plants may compete for light, space, water and mineral ions.
Animals may compete for space, food, water and mating partners.
What is interdependence and a stable community
Interdependence describes how organisms in a community depend on other organisms for vital services.
• These include for food, shelter and reproduction (pollination, seed dispersal), e.g. birds take shelter in trees, flowers are pollinated with the help of bees.
• The removal or addition of a species to the community can affect the populations of others greatly, as it changes prey or predator numbers
• A stable community is one where all the biotic (living) and abiotic (non-living) factors are in balance
As a result the population sizes remain roughly constant.
• When they are lost it is very difficult to replace them.
• Examples include tropical rainforests, oak woodlands and coral reefs.
What abiotic factors affect a community
- Light intensity
• Light is required for photosynthesis.
• The rate of photosynthesis affects the rate at which the plant grows.
• Plants can be food sources or shelter for many organisms. - Temperature
• Temperature affects the rate of photosynthesis. - Moisture levels
• Both plants and animals need water to survive. - Soil pH and mineral content
• Soil pH affects the rate of decay and therefore how fast mineral ions return to soil - Wind intensity and direction
• Wind affects the rate of transpiration in plants.
• Transpiration affects the temperature of the plant, - Carbon dioxide levels
• CO, affects the rate of photosynthesis in plants.
• It also affects the distribution of organisms as some thrive in high CO,
environments. - Oxygen levels for aquatic animals
• Levels in water vary greatly, unlike oxygen levels in air.
• Most fish need a high concentration of oxygen to survive.
What biotic factors affect a community
Food availability: more food means organisms can breed more successfully and therefore the population can increase in numbers
2. New predators
3. New pathogens: when a new pathogen arises the population has no resistance to it so they can be wiped out quickly
4. Competition: if one species is better adapted to the environment than another, then it will outcompete it until the numbers of the lesser adapted species are insufficient to breed.
What adaptations do organisms have
Structural: shape or colour of a part of an organism, e.g.
• Sharp teeth of a carnivore to tear meat apart
• Camouflage, such as the tan/brown colour of a lionesses coat, to avoid prey from spotting her
• Species in cold environments may have a thick layer of fat for insulation
2. Behavioural: the way an organism behaves, e.g.
Individuals may play dead to avoid predators
Basking in the sun to absorb heat
• Courting behaviour to attract a mate
3. Functional: involved in processes such as reproduction and metabolism
Late implantation of embryos
• Conservation of water through producing little sweat
What’s a extremophile
Something that lives in extreme conditions
Examples of animal adaptations
Cold climates: Smaller surface area to volume ratio to reduce heat loss, lots of insulation (blubber, fur coat)
2. Dry climates: Adaptations to kidneys so they can retain lots of water producing very concentrated urine, being active in the early morning and evenings when it is cooler, resting in shady areas, larger surface area ratio to increase heat loss
3. Examples of plant adaptations: Curled leaves to reduce water loss, extensive root systems to take in as much water as possible, waxy cuticle to stop water evaporating,
What are the feeding relationships shown on the food chains
They begin with a producer.
• These are always photosynthetic organisms (usually a green plant or algae)
• Through photosynthesis they make glucose
• Glucose is used to make other biological molecules in the plant, which make up the biomass
2. Producers are eaten by primary consumers - energy is transferred through
organisms in an ecosvstem when one is eaten by another.
3. Primary consumers are eaten by secondary consumers - The animals eaten are called the prey and the consumers that kill and eat them are predators.
4. Secondary consumers are eaten by tertiary consumers.
The carbon cycle
• CO, is REMOVED from the air in photosynthesis by green plants and algae - they use the carbon to make carbohydrates, proteins and fats. They are eaten and the carbon moves up the food chain.
• CO, is RETURNED to the air when plants, algae and animals respire.
Decomposers (a group of microorganisms that break down dead organisms and waste) respire while they return mineral ions to the soil.
• CO, is RETURNED to the air when wood and fossil fuels are burnt (called
combustion) as they contain carbon from photosynthesis.
The water cycle
• The sun’s energy causes water to evaporate from the sea and lakes, forming water vapour.
• Water vapour is also formed as a result of transpiration in plants.
• Water vapour rises and then condenses to form clouds.
• Water is returned to the land by precipitation (rain, snow or hail), and this runs into lakes to provide water for plants and animals.
• This then runs into seas and the cycle begins again.
What does high biodiversity mean for an ecosystem
Species are less depended on each other for things such as food and shelter
How is human impact affecting wildlife
More land is being used for houses, farming, shops, roads and factories, which destroys habitats.
• Pollution kills plants and animals.
• Sewage, fertiliser and toxic chemicals pollute the water.
• Smoke and acidic gases pollute the air.
Landfill and toxic chemicals can result in the pollution of the land.
• We are using up raw materials quicker than they are being produced.
What are peat bogs
Peat is a material that forms when plant material has not fully decayed as there is not enough oxygen.
• It accumulates in bogs that are acidic and waterlogged.
• These bogs are a habitat for many species, in particular for migrating birds
• Peat bogs are being destroyed - they are being drained in order to create space for farming, peat is used as compost, or dried to use as fuel as it contain carbon
Problems of deforestation
Trees take in CO, when they photosynthesise, so less trees means less CO, is
3. The number of habitats are reduced, decreasing biodiversity.
