Ecology

Seite 1

Competition

Habitat - where organism lives

Population - all organisms of one species living in a habitat

Community - populations of different species living in a habitat

Abiotic factors - non-living factors of environment

Biotic factors - living factors of environment

Ecosystem - interaction of a community of living organisms with non-living parts of their environment

Organisms need things from their environment and other organisms to survive and reproduce:

Plants need light and space - and water and mineral ions

Animals need space, food, water and mates

Organisms compete with other species (and their own species) for the same things

Each species depends on other species for things such as food, shelter, pollination and seed dispersal

Interdependence - any major change can have far-reaching effects

In some communities, all species and environmental factors are in balance so that population size are roughly constant - stable communities

Stable communities include tropical rain-forests and ancient oak woodlands

Seite 2

Abiotic and Biotic Factors

Abiotic - non-living factors, for example:

Moisture level

Light intensity

Temperature

Carbon Dioxide level

Wind intensity and direction

Oxygen level

Soil pH and mineral content

Change in environment could be an increase or decrease in abiotic factors

Changes affect size of populations in a community

Also affect population sizes of other organisms that depend on them

Decrease in light intensity, temp or level of CO2 could decrease rate of photosynthesis

Decrease in mineral content could cause nutrient deficiencies

Biotic factors - living things, for example:

New predators

Competition

New pathogens

Availability of food

Change in environment could be information of introduction of new biotic factor

Can affect size of populations in a community - can have knock on effects

New predator - could cause decrease in prey population

Red and grey squirrels - live in the same habitat and eat same food

Grey squirrels - population of red squirrels decreases

Seite 3

Adaptations

Organisms are adapted to live in different environmental conditions

Features/characteristics allow them to do this - adaptations

Structural

Features of body structure - shape and colour (for example)

Artic animals - white fur for camouflage - avoid predators and sneak up on prey

Animals that live in cold places - thick layer of blubber and a low surface area to volume ratio - help them retain heat

Animals that live in hot places - thin layer of fat and a large surface area to volume ratio to help them lose heat

Behavioural

Way organisms behave

Many species migrate to warmer climates during water to avoid problems in cold conditions

Functional

Things that go on with an organism's body that can be related to processes like reproduction and metabolism

Desert animals conserve water by producing very little sweat and small amounts of concentrated urine

Brown bears hibernate over winter - lower their metabolism which conserves energy - don't have to hunt when there's not much food

Organisms can live in a wide range of environments:

Some microorganisms are known as extremophiles - they're adapted to live in very extreme conditions

Some can live at high temperatures

Others can live in places with a high salt concentration or at high pressures

Seite 4

Food Chains

Always start with producer

Make their own food using energy from the Sun

Usually green plants or algae - make glucose from photosynthesis

Some of it is used to make other biological molecules - biomass

Biomass - energy stored in a plant

Energy is transferred through living organisms in an ecosystem when organisms eat other organisms

Producers are eaten by primary consumers which are then eaten by secondary consumers and they're eaten by tertiary consumers ​​​​​​

Predators - hunt and kill other animals

Prey - what predators eat

In a stable community containing prey and predators:

​​​​​​​Population of any species is usually limited by amount of food available

​​​​​​​If population of prey increases, then so will population of predators

​​​​​​​As population of predators increases, number of prey will decrease

​​​​​​​Predator-prey cycles are always out of phase with each other

​​​​​​​It takes a while for one population to respond to changes in other population ​​​​​​​

Seite 5

The Water Cycle

Water is constantly recycled:​​​​​​

1. Energy from Sun makes water evaporate from land and sea, turning it into water vapour ​​​​​​​

​​​​​​​2. Water also evaporates from plants - known as transpiration

​​​​​​​3. Warm water vapour is carried upwards - when it gets higher it cools and condenses to form clouds

​​​​​​​4. Water falls from clouds as precipitation onto land - where it provides fresh water for plants and animals

​​​​​​​5. Some of this is absorbed by the soil and is taken up by plant roots - provides plants with fresh water for things like photosynthesis ​​​​​​​​​​​​​​

​​​​​​​​​​​​​​Some of the water taken up by plants becomes part of plants' tissues and is passed along to animals in food chains

​​​​​​​6. Animals need water for chemical reactions - animals return water to soil and atmosphere through excretion ​​​​​​​

​​​​​​​7. Water that doesn't get absorbed by the soil will runoff into streams and rivers

​​​​​​​8. From here, water drains back into sea - before it evaporates all over again

Seite 6

Carbon Cycle

Living things are made of materials from world around them - get passed up food chain

Materials are returned to environment in waste products/when organisms die and decay

Materials decay - they're broken down by microorganisms

​​​​​​​Happens faster in warm, moist, oxygen rich conditions - microorganisms are more active in these environments

​​​​​​​​​​​​​​Decay puts what plants need to grow back into soil ​​​​​​​​​​​​​​​​​​​​​

​​​​​​​Stable community - materials are taken out of soil and used by plants

​​​​​​​​​​​​​​etc. are balanced by those that are put back in - constant cycle

​​​​​​​CO2 removed from atmosphere by photosynthesis ​​​​​​​

​​​​​​​Carbon is used to make glucose - can be turned int carbohydrates, fats and proteins - plants and algae ​​​​​​​

​​​​​​​​​​​​​​When plants and algae respire, some carbon is returned to atmosphere

​​​​​​​When plants/algae are eaten by animals, some carbon becomes parts of fats and proteins in bodies

​​​​​​​Carbon moves through food chain ​​​​​​​

​​​​​​​​​​​​​​​​​​​​​Animals respire ​​​​​​- some carbon is returned to atmosphere as CO2 ​​​​​​​​​​​​​​

​​​​​​​Plants, algae and animals die - others feed on remains

​​​​​​​These respire CO2 is returned to atmosphere ​​​​​​​

​​​​​​​Animals produce waste - broken down by detritus feeders and microorganisms ​​​​​​​

​​​​​​​Combustion of wood and fossil fuels release CO2 back into air

​​​​​​​Carbon (and energy) is constantly being cycled

​​​​​​​From air, through food chains and eventually back into air ​​​​​​​​​​​​​​​​​​​​

Seite 7

Biodiversity and Waste Management

Bodiversity - variety of different species of organisms on Earth/within an ecosystem

High biodiversity - makes sure that ecosystems are stable because different species depend on each other for things like shelter and food

​​​​​​​​​​​​​​Different species can help to maintain the right physical environment for each other

​​​​​​​For human species to survive, it's important that a good level of biodiversity is maintained ​​​​​​​

​​​​​​​Lots of human actions, including waste productions and deforestation as well as global warming are reducing biodiversity

​​​​​​​​​​​​​​It's only recently that we've started taking measures to stop this from continuing

​​​​​​​​​​​​​​Population of the world is currently rising very quickly - not slowing down

​​​​​​​Mostly due to modern medicine and farming methods

​​​​​​​Reduced number of people dying from disease and hunger ​​​​​​​

​​​​​​​Great for all humans - means bigger effect on environment

​​​​​​​​​​​​​​When Earth's population was smaller, effects of human activity were usually small or local

​​​​​​​Now actions have widespread effect

​​​​​​​Increasing population puts pressure on environment - we take resources needed to survive ​​​​​​​

​​​​​​​People around the world are asking for higher standards of living:

​​​​​​​Use more raw materials ​​​​​​​

​​​​​​​Use more energy

​​​​​​​More and more resources from environment more and more quickly

​​​​​​​Many raw materials are being used quicker than they're being replaced ​​​​​​​

​​​​​​​One day they will run out ​​​​​​​

​​​​​​​​​​​​​​​​​​​​​Producing more and more waste - including chemical waste

​​​​​​​Unless this waste is properly handled, more harmful pollution will be caused ​​​​​​​​​​​​​​

​​​​​​​Pollution affects water, land and air - kills plants and animals - reducing biodiversity

​​​​​​​​​​​​​​​​​​​​​​​​​​​​Water

​​​​​​​​​​​​​​​​​​​​​Sewage and toxic chemicals can pollute lakes, rivers and oceans ​​​​​​​

Affects plants and animals that rely on them for survival

​​​​​​​Chemicals used on land can be washed into water

​​​​​​​​​​​​​​​​​​​​​Land ​​​​​​​

​​​​​​​​​​​​​​Use toxic chemicals for farming

​​​​​​​Bury nuclear waste

​​​​​​​Dump household waste in landfill sites

Smoke​​​​​​​

​​​​​​​​​​​​​​Smoke and acidic gases released into atmosphere can pollute air ​​​​​​​

Seite 8

Global Warming

Temp of Earth is balance between energy from Sun and energy radiated into space

Gases in atmosphere act like an insulating layer

Absorb most of energy that would normally be radiated out into space, re-radiated back into all directions - increase temp of planet

If this didn't happen, then all energy will escape and it would be very cold

​​​​​​​Several different gases - help keep energy in

​​​​​​​Called greenhouse gases ​​​​​​​

​​​​​​​Main ones are CO2 and methane - levels are rising sharply

​​​​​​​Earth is gradually heating up - increasing levels of greenhouse gases - global warming ​​​​​​​

​​​​​​​Type of climate change and causes other types of climate change ​​​​​​​

Higher Temperatures

​​​​​​​​​​​​​​Cause seawater to expand ​​​​​​​​​​​​​​and ice to melt - causing sea level to rise

​​​​​​​Has risen slightly over the 100 years

​​​​​​​If it keeps rising, pants and animals may lose habitats

​​​​​​​Lead to flooding

​​​​​​​Distribution of many wild animals and plant species may change

​​​​​​​Amount of rainfall changes in different areas

​​​​​​​Some species may become more widely distributed

​​​​​​​Or some species may become less distributed ​​​​​​​

​​​​​​​Could be changes ​​​​​​​in migration patterns

​​​​​​​Biodiversity could be reduced if some species are unable to survive

​​​​​​​So become extinct ​​​​​​​

Seite 9

Deforestation and Land Use

Use land for things like buildings, quarrying, farming and dumping waste

Less land available for other organisms

​​​​​​​Sometimes the way we use land has a bad effect on the environment

​​​​​​​If it requires deforestation/destruction of habitats ​​​​​​​​​​​​​​​​​​​​​

​​​​​​​​​​​​​​​​​​​​​Cutting down of forests

​​​​​​​Causes big problems when it's done on a large scale ​​​​​​​

​​​​​​​​​​​​​​Done for various reasons

​​​​​​​​​​​​​​To clear land for farming

​​​​​​​To grow crops from which biofuels can be produced

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Less CO2 taken ​​​​​​​​​​​​​​​​​​​​​

​​​​​​​​​​​​​​​​​​​​​​​​​​​​Cutting down lots of trees means amount of CO2 removed from atmosphere during photosynthesis is reduced

​​​​​​​Trees "lock up" some of the carbon that they absorb during photosynthesis in their wood

​​​​​​​​​​​​​​Can remove it from atmosphere for hundreds of years

​​​​​​​Removing trees means that less is locked up

​​​​​​​​​​​​​​​​​​​​​​​​​​​​More CO2 in the atmosphere

​​​​​​​​​​​​​​​​​​​​​CO2 is released when trees are burnt to clear land

​​​​​​​Carbon in wood doesn't contribute to atmospheric pollution until it's released by burning

​​​​​​​Micro-organisms feeding on bits of dead wood release CO2 as a waste product of respiration

​​​​​​​​​​​​​​Less Biodiversity

​​​​​​​​​​​​​​​​​​​​​Variety of different species - more species, greater biodiveristy

​​​​​​​Habitats like forests can contain a huge number of different species of plants and animals

​​​​​​​​​​​​​​When they're destroyed there is a danger of many species becoming extinct - biodiversity is reduced

​​​​​​​​​​​​​​​​​​​​​Bogs are areas of land that are acidic and waterlogged

​​​​​​​​​​​​​​Plants that live in bogs don't fully decay when they die - there's not enough oxygen

​​​​​​​Partly-rotted plants gradually build up to form peat

​​​​​​​​​​​​​​Carbon in plants is stored in peat instead of releasing it into atmosphere ​​​​​​​

Pare often drained so area can be used as farmland, or peat is cut up and dried to use as fuel

​​​​​​​Also sold to gardeners as compost

​​​​​​​Used faster than it forms

​​​​​​​When drained, it comes into more contact with air and some micro-organisms start to decompose it

​​​​​​​When these respire, they use oxygen and release CO2 contributing to global warming

​​​​​​​​​​​​​CO2 is released when peat is burned as a fuel

​​​​​​​Destroying bogs also destroys (or reduces area of) habitats of some of the animals, plants and micro-organisms that live there - reduces biodiversity

Seite 10

Maintaining Ecosystems and Biodiversity

Important biodiversity is maintained at high enough level to make sure that ecosystems are stable

In some areas, programmes have been set up by concerned citizens and scientists ​​​​​​to minimise dame by human activities to ecosystems and biodiversity

​​​​​​​​​​​​​​Breeding programmes

​​​​​​​Set up to prevent endangered species from extinction ​​​​​​​

​​​​​​​Where animals are bred in captivity to make sure species survives if it dies out in the wild

​​​​​​​Individuals can sometimes be released into the wild to boost or re-establish a population

​​​​​​​Programmes - protect and regenerte rare habitats​​​​​​​

​​​​​​​Like mangroves, heathland and coral reefs ​​​​​​​

​​​​​​​Protecting habitats helps to protect species that live there

​​​​​​​Preserving ecosystem and biodiversity ​​​​​​​

​​​​​​​​​​​​​​​​​​​​​​​​​​​​Programmes to reintroduce hedgerows and field margins

​​​​​​​​​​​​​​​​​​​​​Where only a single type of crop is grown

​​​​​​​Field margins are areas of land around edges of fields where wild flowers and grasses are left to grow

​​​​​​​Provide a habitat for a wider variety of organisms that could survive in a single crop habitat

​​​​​​​Programmes to reduce level of deforestation and amount of CO2​​​​​​​

​​​​​​​Could reduce the increase of global warming ​​​​​​​​​​​​​​​​​​​​​

Recycling

Reduce amount of waste that gets dumped in landfill sites

​​​​​​​Could reduce amount of land taken for landfill - leaving ecosystems

Maintaining biodiversity isn't as simple as people hope

There are lots of conflicting pressures that must be taken into account

​​​​​​​Costs money​​​​​​​​​​​​​​​​​​​​​

Governments sometimes pay farmers a subsidy to reintroduce hedgerows and field margins to their land

​​​​​​​Can cost money to keep a watch on whether programmes and regulations designed to maintain biodiveristy

​​​​​​​​​​​​​​​​​​​​​May come at a cost to local people's livelihood ​​​​​​​

​​​​​​​Reducing amount of deforestation is great for biodiversity​​​​​​​

​​​​​​​People who were previously employed in tree-felling industry could be left unemployed

​​​​​​​Could affect local economy if people move away with families to find work

​​​​​​​​​​​​​​Can be conflict between biodiversity and protecting food security

​​​​​​​​​​​​​​​​​​​​​Certain organisms are seen as pests by farmers and are killed to protect crops and livestock so more food can be produced

​​​​​​​Food chain and biodiversity can be affected

​​​​​​​Development is important - it can affect environment ​​​​​​​

​​​​​​​​​​​​​​Many want to protect biodiversity in the face of development

​​​​​​​Sometimes land is in such high demand that previously untouched land with high biodiversity has to be used for development