Ecosystems and material cycles

What is an ecosystem?

All the living organisms and the environment in which they live

What is population?

Groups of the same species in the same ecosystem

What is a community?

All the organisms that live and interact in an area

What is a habitat?

the natural home or environment of an animal, plant, or other organism.

What does interdependence mean?

All animals and plants in an ecosystem interact and depend on each other for food, shelter and so on

What are abiotic factors?

A non-living part of an ecosystem that changes its environment

What are some examples of abiotic factors? (Name 5)

Sunlight, wind, weather, temperature, climate, altitude, water sources, humidity, salinity(salt), oxygen concentration, pH of soil, space available, nutrient availability

What does abundance mean?

How common something is

What is a food web?

A diagram of interlinked food chains. It shows how the feeding relationships are interdependent

What is a resource?

Something that an organism needs to stay alive- such as food water and space

What is a quadrat and what is it used for?

A square frame of a known area used to get a sample of the organisms living in a small area

What are 4 different ways to estimate population?

\-Capture, mark, release

\-Pitfall trap

\-Quadrats

\-Belt transect

How do you use a belt transect?

• The method involves laying out a transect line and then placing quadrats over the line at regular intervals, starting the quadrat at the first marked point of the line.

• Any consistent measurement size for the quadrat and length of the line can be chosen, depending on the species.

• Changes in factors such as temperature and light intensity are also recorded making it easier to link a change in distribution with a physical change

What are biotic factors?

Living components in an ecosystem that affect other living organisms. This includes predators that eat each other and competition for resources such as light, water and space.

What is biodiversity?

Lots of different types and species of life

What are parasites?

An organism that lives in or on an organism of another species (its host) and benefits by deriving nutrients at the other's expense.

What are some examples of parasites?

Tapeworms, pinworms, hookworms, protazoa

What is mutualism?

A type of symbiotic relationship where all species involved benefit from their interactions

What does indigenous mean?

Organisms that have always been in an area/country

What does non-indigenous mean?

Organisms that were introduced to an area and were not always found there

What is meant by an endangered species?

A species that is in danger of going extinct

What does conservation mean?

To maintain and increase numbers of species

How can some species be conserved?

Putting animals in a zoo or growing more of a type of plant, for example

What is the water cycle?

The process which recycles water

What is transpiration?

Plants losing water through their leaves

What is evaporation?

The process of liquid turning to gas

What is precipitation?

Any form of rain, snow or sleet

What is condensation?

The process of gas truing to liquid

What are the stages of the water cycle?

• Transpiration/Evaporation: Water evaporates from the sea, land and plants and becomes water vapour

• Condensation: As air rises it cools and condenses forming clouds

• Precipitation: Water droplets become heavy and start to fall as rain or snow and the water is returned to Earth

• Some of the water evaporates again and some runs off the surface into the sea or rivers

• Some water filters down into the ground to underground natural reservoirs

• Infiltration: Ground water from natural reservoirs finds its way to rivers through soil and rock

• Rivers flow into lakes and will return to the ocean

Steps of the carbon cycle

• Plants use sunlight and carbon dioxide from the atmosphere for photosynthesis

• Photosynthesis produces oxygen and an organic carbon source. The carbon source is eaten by animals.

• Plants and animals use glucose and oxygen to carry out cellular respiration they release carbon dioxide into the atmosphere

• Animals and plants that die that are not broken down by decomposers such as bacteria and fungi form fossil fuels.

• Factory emissions burn fossil fuels and release carbon dioxide back into the atmosphere

What happens in the Nitrogen cycle

• Nitrogen in the air is converted to nitrates in the soil by nitrogen fixing bacteria

• The nitrates are absorbed by plants and made into amino acids

• Animals eat some of these plants and the amino acids are passed into animals

• When plants and animals die (or through animal excrement) there is nitrogen in their remains

• Decomposing bacteria turn this into ammonia

• Nitrifying bacteria then converts the ammonia to nitrates to be absorbed into plants again

• Denitrifying bacteria breaks down some of the nitrates into nitrogen which goes back into the air

What are fertilisers?

 Concentrated sources of plant nutrients usually in compact form such as pellets, granules, powders or liquids. They are used to improve plant growth and yields.

Advantages of fertilisers?

• They are quick in providing plant nutrients and restoring soil fertility.

• They are portable and easy to transport.

• Plants easily absorb fertilizers.

• Fertilizers improve and increase the productivity of many crops such as wheat, maize, and rice

• Increases crop yield

Disadvantages of fertilisers?

* They get washed away by water easily and cause pollution.
* They harm the microbes present in soil.
* They reduce soil fertility.
* They are expensive.
* They provide only short term benefits.
* They change the nature of soil, making it either too acidic or too alkaline.

What is eutrophication?

Eutrophication is the process that can happen in a water body, like a river or a lake, when too many nutrients are added to the system.

What is algal bloom in eutrophication?

• Fertiliser from fields is washed away by rain into a body of water

• Algal bloom is when the algae absorb all the nutrients from the fertiliser and grow and rapidly

Why is algal bloom a problem in eutrophication?

Because the algal bloom will absorb all the sunlight from the surface and the plants underneath will not get enough sunlight to do photosynthesis and will die. The algae will also die when all the nutrients are used up and they have no food.

After algal bloom, what begins to break down the dead plants and algae?

Bacteria

What does breakdown of plants and algae cause in eutrophication?

More nutrients being released which leads to the algal bloom cycle continuing

What does anoxic mean?

 A condition in which oxygen is completely absent or depleted

Why does the water become anoxic in eutrophication?

Because the bacteria are growing and respiring which uses oxygen.

What happens if the water become anoxic in eutrophication?

all non-bacterial life in the water, including fish and other animals, will die.

What is an organism?

A single living individual

What is distribution affected by?

Factors in the environment

What are some living environmemtal factors that affect distribution?

• Prey

• Competitor

• Predator

What are some non-living environmental factors that affect distribution?

• Light

• Average temperature

• Average rainfall

• Oxygen levels in water

• Pollution

What is a pollutant?

Energy or a chemical that has an effect on living organisms

What are oxygen levels like in polluted water?

In polluted water they are low whereas in unpolluted water they are high

What are some ways organisms protect themselves from predators?

• Some display they are poisonous with very bright colours

• Some animals use colours to make them look more frightening

• Some plants have large thorns

• Other plants are poisonous

How does competition arise in an ecosytem?

• Organisms need a supply of materials from their surroundings and sometimes other organisms so they can survive and reproduce

• This causes competition for materials in short supply

What do plants compete for?

• Light

• Space

• Water

• Nutrients

What do animals compete for?

• Food

• Mates for reproduction

• Territory

How do parasites use their hosts?

• Some like fleas and had lice suck the blood from animals

• Some like tapeworms live in the animals small intestine where the absorb nutrient from the digested food in the intestine

• Some like mistletoe grow roots into tress to absorb water and nutrients

What are some ways mutualism benefits both organisms?

• One animal will feed off the dead skin and parasites from another organism

  • This means that the first organism will get food and the second benefit from the loss of dead skin and parasites

• Nitrogen fixing bacteria in root nodules are protected from the environment and get food from the plant they are on and the legume plant will get nitrogen compounds for healthy growth from the bacteria

How do we use quadrats?

• Coordinates are made for an areas in the field

• A system can be used to produce a random coordinate in this area for the quadrat to be placed in

• The number of organisms is counted in each area

How are the number of organisms in an area estimated with quadrats?

Mean number of organisms in one quadrat x total area/area of quadrat

Why do we use samples to estimate population or distribution?

The areas we want to analyse are too large to count every individual organism

What do we use to study the affect of biotic or abiotic factors on organisms?

Belt transect

Where is energy stored in an organism?

In it’s biomass

What are trophic levels?

The feeding levels in a food chain or food web

What happens to energy as it is stored as biomass in the next trophic level?

• Not all energy from one trophic level is stored as biomass in the next

• Some of the energy is transferred to the environment

• Energy lost as heat is not as useful as it cannot be converted to biomass again

How do energy transfers happen in plants?

• Energy transferred by light during photosynthesis

• Energy stored in new plant biomass which can be transferred to herbivores in their food

• Energy from respiration transferred to the surroundongs

How do energy transfers happen in animals?

• Energy stored in biomass from food

• Energy stored as new animal biomass which can be transferred to carnivores in their food

• Energy is stored in substances like faeces and urine

• Energy from respiration transfers energy to surroundings as heat

What are pyramids of biomass?

• A diagram that shows he amount of biomass at each trophic level

• The producer is the bottom bar and the other show the trophic levels in order

• The amount of biomass at each trophic level gets smaller as some energy is transferred to heating the environment

• These are usually only 4 or 5 levels because the biomass at the top is not enough to provide the energy needed for another level

What is biomass?

The mass of an organisms body tissue

What is fish farming?

• Growing one kind of fish in an area

• The fish are fed and the waste they produce are removed from their tanks

What are the advantages and disadvantages of fish farming?

• Waste can pollute the local area, changing conditions which could cause some species to die out

• Diseases from the farmed fish can spread to wild fish and kill them

• Farming fish reduces the fishing of wild fish

What are the positives and negatives of introducing a non-indigenous species into an area?

• They may reproduce rapidly as they have no natural predators

• They may out-compete native species for food and other resources

• They may provide food for native species

What reasons do humans have for maintaining biodiversity?

• Morality: Humans should respect other living organisms

• Aesthetic: People enjoy seeing the variety in an ecosystem

• Ecosystem structure: Some organisms have important roles to play and if the planet loses species, the food chain becomes more unstable

• Usefulness: Some organisms such as plants that produce life saving drugs are very important to humans

What is reforestation?

Replanting forests where they have been destroyed

What are the advantages of reforestation?

• Restores habitat for species that are endangered

• Reduces concentration of carbon dioxide in the air through photosynthesis

• Tree roots bind the soil together and reduce the effects of soil erosion

• Affects local climate, for example reducing the range of temperature variation

What is food security?

• Having a reliable and adequate food supply

• Increasing human population need greater food security

• As people become more well off, there is a higher demand for meat and fish

What are the effects of increased food demand?

• Increasing human population means more food is needed

• Increased demand of meat and fish means more land is used for farming and a has greater impact on wild fish population either due to wild fishing or fish farming

• Movement of people and goods introduces pests into an area, damaging local crops and animals

• Increased waste is produced, leading to pollution

How does human activity affect availability of land and food?

Environmental impacts caused by humans such as global warming reduces availability for land to farm on due to rising sea levels, which the leads to less food being produced

Why is the carbon cycle important?

• Carbon dioxide is limited and must be recycled

• It recycles carbon dioxide released in respiration to plants in photosynthesis, to make organic molecules in living animals

Why do plants need nitrates?

• To grow well

• Nitrogen is needed to make proteins for healthy growth

What is crop rotation?

Growing different crops each year, on a rotation basis

How does crop rotation improve soil fertility?

• Different crops remove different nutrients from the soil

• Plants such as clover have nitrogen fixing bacteria in their roots, and can be ploughed back into the soil, to add nitrates

What are indicator species useful for?

Assessing levels of pollution

Why is assessing levels of pollution important?

• Some species are well adapted to living in polluted conditions

• Other species can only live if there is no pollution

• Changes in the abundance of these species can show changes in the level of pollution

How do some species of lichen work as an indicator of air pollution?

• Some species of lichen can only grow where there is no pollution

• Other species can grow where there is air pollution

• The species of lichen growing on trees can tell you if the air has been polluted

How does blackspot work as an indicator of air pollution?

• Blackspot is a fungus that infects roses

• The fungus is damaged by sulfur dioxide in the air

• Where there is air pollution, the roses are clear of the fungus

How do bloodworms and sludgeworms work as indicators of water pollution?

They can live in water that contains very little oxygen so they are found in polluted water

How do stonefly larvae, mayflies and some caddisflies work as indicators of air pollution?

• They can only live in water that contains a lot oxygen

• This means they are indicators of unpolluted water

What is decay?

The break down (digestion) of materials by microorganisms

What is the rate of decomposition affected by and why?

• Warm temperatures because this increases enzyme activity in microorganisms

• Water content because microorganisms need water for many cell processes to work

• Oxygen availability because microorganisms need oxygen for respiration

How can we prevent the decay of food?

• Refrigeration cools food down and the temperature is too cold for most microorganisms to grow quickly

• Salting food causes water to move out of bacterial cells by osmosis, so there is not enough water in the microorganism’s cells to grow

• Packing food in nitrogen means there is no oxygen for microorganisms to respire

How do we recycle kitchen and garden waste?

• Kitchen and garden waste can be used to make compost

• Conditions in compost should encourage the growth of decay microorganisms, which grow and digest faster in conditions that are: moist, warm and aerobic (oxygen present)

How do we calculate the rate of decay?

Rate of decay = (Loss in mass in grams)/time in days

What does potable water mean?

Drinkable water

What is desalination?

• Producing drinking water from salty water

• This can be done by distillation

Why is desalination important?

• Some countries where it is very hot and dry suffer from drought

• They do not get enough drinking water from precipitation as their source of potable water