Standard Grade Biology - The Biosphere

An ecosystem is a natural biological unit made up of all living things, their non-living surroundings and factors affect their lives. It is made up of different components that are common to all ecosystems.

Community & Habitat = ECOSYSTEM

Species

A group of very similar plants or animals that can interbreed and produce fertile offspring, eg. rabbits or beech trees.

Population

Total number of one species living in an ecosystem.

Community

The total number of all different species living in an ecosystem.

Habitat

The place where an organism lives.

Species

A group of very similar plants or animals that can interbreed and produce fertile offspring, eg. rabbits or beech trees.

Population

Total number of one species living in an ecosystem.

Community

The total number of all different species living in an ecosystem.

Habitat

The place where an organism lives.

• Quadrats
• Transects
• Pitfall Traps
• Tree Beating
• Tullgren
• Funnels
• Pooters
• Netting

There are two type of keys commonly used.

• Biological Key
• Paired Statement Key

A Pitfall Trap is used to take animal samples.

The cup is placed in a hole, making sure that the top is level with the ground so that the animals fall in. However, some animals that fall in may be eaten by predators, such as spiders which also fall in.

• Quadrats
• Transects
• Pitfall Traps
• Tree Beating
• Tullgren
• Funnels
• Pooters
• Netting

A Quadrat is used to take plant samples.

A Quadrat is a frame divided into squares. It is thrown randomly on the area being sampled. The number of squares which contain the plant being studied are counted, not the number of plants in each square.

A Quadrat is used to take plant samples.

A Quadrat is a frame divided into squares. It is thrown randomly on the area being sampled. The number of squares which contain the plant being studied are counted, not the number of plants in each square.

A Pitfall Trap is used to take animal samples.

The cup is placed in a hole, making sure that the top is level with the ground so that the animals fall in. However, some animals that fall in may be eaten by predators, such as spiders which also fall in.

An abiotic factor is a physical factor, such as..

• Light Intensity
• Moisture
• Oxygen
• Concentration
• Temperature
• pH
• Rainfall
• Wind Direction

• Predators
• Disease
• Avaliable Food
• Competition

Measuring Moisture

A moisture meter is used. To avoid errors, you must be careful that you place the moisture probe firmly in the ground and wipe dry afterwards.

Measuring Light

A light meter is used. To avoid errors, you must be careful not to shade the meter and always hold it the same way when making the reading.

Producers - Green plants use the sun's energy to produce food energy.

Consumers - Animals that get their energy from eating other living things.

Primary Consumers - Animals that eat the consumers.

Secondary Consumers - Animals that eat the primary consumers.

Tertiary Consumers - Animals that eat the secondary consumers.

Herbivores - Animals that only eat plants.

Carnivores - Animals that only eat animals.

Top Carnivores - Animals that are not eaten by anything else except decomposers after they die.

The way energy, in the form of food, passes from plants to animals and then to other animals can be shown by a food chain. The arrows in the food chain show the direction of energy flow. Food chains and webs begin with energy from the sun.

A food web gives us a more complete picture of who eats what. Most animals in a community eat more than on thing, if one kind of food runs out, they will be able to survive by eating something else. Food webs are made up of many food chains linked together. Food chains can be drawn for any enviroment.

A Pitfall Trap is used to take animal samples.

The cup is placed in a hole, making sure that the top is level with the ground so that the animals fall in. However, some animals that fall in may be eaten by predators, such as spiders which also fall in.

Energy is needed by all living things. In an ecosystm there is a flow of energy from the sun through the producers to the consumers. There is a loss of energy at each link of a food chain.

Animals can convert about 10% of their food into new tissure by growing. The remaining 90% of food eaten is used for other life functions. These activites use energy which is lost from the food chain.

Energy can be lost in a consumer..

• Heat in respiration
• Urine & Feaces
• Growth

A food web gives us a more complete picture of who eats what. Most animals in a community eat more than on thing, if one kind of food runs out, they will be able to survive by eating something else. Food webs are made up of many food chains linked together. Food chains can be drawn for any enviroment.

An abiotic factor is a physical factor, such as..

• Light Intensity
• Moisture
• Oxygen
• Concentration
• Temperature
• pH
• Rainfall
• Wind Direction

As you move along a food chain, very often the size of organism increases but the number of them decreases. This can be shown by drawing a pyramid. Sometimes a pyramid of numbers does not look like a pyramid at all as it does not take into account the size of the organisms.

• Predators
• Disease
• Avaliable Food
• Competition

A more accurate idea of the quantity of animal and plant material in a food chain is obtained bu constructing a pyramid of biomass. This represents the mass of all the organisms at each level and gives a much better representation of the actual quantity of animal and plant material at each level.

Measuring Moisture

A moisture meter is used. To avoid errors, you must be careful that you place the moisture probe firmly in the ground and wipe dry afterwards.

Measuring Light

A light meter is used. To avoid errors, you must be careful not to shade the meter and always hold it the same way when making the reading.

The total numver of one kind of organism is called population. Many factors affect the size of population.

Most populations tend to stay roughly the same size over a period of time. They may go up and down, but the average population will probaly stay the same over a number of years. There must, therefore, be some check on the numbers in a population which prevents a population explosion.

eg. Various factors which could limit the size of population..

• Predators
• Disease
• Lack Of Food
• Lack Of Space

Id different organisms eat the same food the competition will occur. Plants compete for light and water: Animals compete for food and a plce to live. When competition occurs, some organisms will be more successful than others. These organisms will be more likely to survive.

Producers - Green plants use the sun's energy to produce food energy.

Consumers - Animals that get their energy from eating other living things.

Primary Consumers - Animals that eat the consumers.

Secondary Consumers - Animals that eat the primary consumers.

Tertiary Consumers - Animals that eat the secondary consumers.

Herbivores - Animals that only eat plants.

Carnivores - Animals that only eat animals.

Top Carnivores - Animals that are not eaten by anything else except decomposers after they die.

Bacteria and fungi are very important in an ecosystem. They feed on dead ani,als and plants and are known as decomposers.

Decomposers are important because..

• They get rid of dead animals and plants.
• They release chemicals from dead organisms which go into the soil and help keep it fertile. These chemicals are taken up as nutrients by living organisms as part of nutrient cycle.

The way energy, in the form of food, passes from plants to animals and then to other animals can be shown by a food chain. The arrows in the food chain show the direction of energy flow. Food chains and webs begin with energy from the sun.

All living things need nitrogen to make protein. Plants obtain nitrogen from the soil by taking nitrates. Animals obtain nitrogen by eating plants or other animals.

Nitrogen fixing means absorbing nitrogen gas from the atmosphere to make nitrates. Some bacteria in the soil can so this. Also, some plants (eg. peas and clover) have swellings (nodules) on their roots in which these types of bacteria live.

Carbon dioxide is a rare atmospheric gas. It makes up 0.03% of the atmosphere. This amount should stay the same, as the carbon is recycled. The amount of carbon released into the atmosphere balances the amount absorbed by plants.

Bacteria and fungi break down dead material. Decomposers also recycle other nutrients into the soil besides carbon. During photosynthesis plants take up these nutrients which are dissolved in water. Ideal conditions for decompostition are warmth, moisture and oxygen.

Pollution occurs when the presense of a substance (the pollutant) in an enviroment causes harm to organisms, looks unslightly or causes damage to bulidings etc.

Pollution affects air, fresh water, sea and land.

Energy is needed by all living things. In an ecosystm there is a flow of energy from the sun through the producers to the consumers. There is a loss of energy at each link of a food chain.

Animals can convert about 10% of their food into new tissure by growing. The remaining 90% of food eaten is used for other life functions. These activites use energy which is lost from the food chain.

Energy can be lost in a consumer..

• Heat in respiration
• Urine & Feaces
• Growth

Main sources of pollution are..

Domestic - Sewage, household rubbish.

Agricultural - Pesticides, excess fertilisers.

Industrial - Organic waste, sulphur dioxide, poisonous gases.

As you move along a food chain, very often the size of organism increases but the number of them decreases. This can be shown by drawing a pyramid. Sometimes a pyramid of numbers does not look like a pyramid at all as it does not take into account the size of the organisms.

The energy industry produces electricity. Most our of electricity comes from power stations which burn fossil fuels (coal,oil,gas).

Fossil fuels release harmful gases (such as sulphur dioxide and nitrogen dioxide) into the air when they are burned. When these gasses dissolve in rainwater, they form acid rain.

Acid rain kills fish and trees and damages buildings, particularly those made of limestone. Acid rain falls into lakes and posions fish and birds.

A more accurate idea of the quantity of animal and plant material in a food chain is obtained bu constructing a pyramid of biomass. This represents the mass of all the organisms at each level and gives a much better representation of the actual quantity of animal and plant material at each level.

Pesticides used on farms can be washed into rivers and damage habitats and organisms.

Need more information on fertilisers & pesticides? Check out my Standard Grade Geogrpahy - Farming revision notes.

The total numver of one kind of organism is called population. Many factors affect the size of population.

Most populations tend to stay roughly the same size over a period of time. They may go up and down, but the average population will probaly stay the same over a number of years. There must, therefore, be some check on the numbers in a population which prevents a population explosion.

eg. Various factors which could limit the size of population..

• Predators
• Disease
• Lack Of Food
• Lack Of Space

Sewage is a common pollutant. Waste such as this is called organic waste. It can cause many changes in water enviroments if it is not treated at a sewage plant before released into the wider enviroment.

Organic waster provides food for bacteria and allows them to gtow and reproduce.

When bacteria feed on sewage, they use up oxygen in the water. This means that there is less oxygen for other organisms such as fish and insects.

As the concentration of sewage pollution rises, the population od bacteria rises. This is because the bacteria feed off the sewage which provides raw materials and energy for growth and reproduction. At the same time, the concetraton of the oxygen falls. This is because the bacteria use up the oxygenas they break down the organic waste in the sewage. Consequently, animals, such as fish, stonefly nymphs and shrimps, decrease in numbers.

Id different organisms eat the same food the competition will occur. Plants compete for light and water: Animals compete for food and a plce to live. When competition occurs, some organisms will be more successful than others. These organisms will be more likely to survive.

Some animals are only able to live in water that contains alot of oxygen. Other animals can survive in water that contains little or no oxygen. The presenceor absence of particular organisms can indicate whether the water is polluted or not. These animals are called indicator species.

Animals found in water with low levels of oxygen - sludge worm, rat-tailed maggot, blood worm.

Animals found in areas with high levels of oxygen - mayfly nymph, stonefly nymph, shrimp.

Bacteria and fungi are very important in an ecosystem. They feed on dead ani,als and plants and are known as decomposers.

Decomposers are important because..

• They get rid of dead animals and plants.
• They release chemicals from dead organisms which go into the soil and help keep it fertile. These chemicals are taken up as nutrients by living organisms as part of nutrient cycle.

All living things need nitrogen to make protein. Plants obtain nitrogen from the soil by taking nitrates. Animals obtain nitrogen by eating plants or other animals.

Nitrogen fixing means absorbing nitrogen gas from the atmosphere to make nitrates. Some bacteria in the soil can so this. Also, some plants (eg. peas and clover) have swellings (nodules) on their roots in which these types of bacteria live.

Carbon dioxide is a rare atmospheric gas. It makes up 0.03% of the atmosphere. This amount should stay the same, as the carbon is recycled. The amount of carbon released into the atmosphere balances the amount absorbed by plants.

Bacteria and fungi break down dead material. Decomposers also recycle other nutrients into the soil besides carbon. During photosynthesis plants take up these nutrients which are dissolved in water. Ideal conditions for decompostition are warmth, moisture and oxygen.

Pollution occurs when the presense of a substance (the pollutant) in an enviroment causes harm to organisms, looks unslightly or causes damage to bulidings etc.

Pollution affects air, fresh water, sea and land.

Main sources of pollution are..

Domestic - Sewage, household rubbish.

Agricultural - Pesticides, excess fertilisers.

Industrial - Organic waste, sulphur dioxide, poisonous gases.

The energy industry produces electricity. Most our of electricity comes from power stations which burn fossil fuels (coal,oil,gas).

Fossil fuels release harmful gases (such as sulphur dioxide and nitrogen dioxide) into the air when they are burned. When these gasses dissolve in rainwater, they form acid rain.

Acid rain kills fish and trees and damages buildings, particularly those made of limestone. Acid rain falls into lakes and posions fish and birds.

Pesticides used on farms can be washed into rivers and damage habitats and organisms.

Need more information on fertilisers & pesticides? Check out my Standard Grade Geogrpahy - Farming revision notes.

Sewage is a common pollutant. Waste such as this is called organic waste. It can cause many changes in water enviroments if it is not treated at a sewage plant before released into the wider enviroment.

Organic waster provides food for bacteria and allows them to gtow and reproduce.

When bacteria feed on sewage, they use up oxygen in the water. This means that there is less oxygen for other organisms such as fish and insects.

As the concentration of sewage pollution rises, the population od bacteria rises. This is because the bacteria feed off the sewage which provides raw materials and energy for growth and reproduction. At the same time, the concetraton of the oxygen falls. This is because the bacteria use up the oxygenas they break down the organic waste in the sewage. Consequently, animals, such as fish, stonefly nymphs and shrimps, decrease in numbers.

Some animals are only able to live in water that contains alot of oxygen. Other animals can survive in water that contains little or no oxygen. The presenceor absence of particular organisms can indicate whether the water is polluted or not. These animals are called indicator species.

Animals found in water with low levels of oxygen - sludge worm, rat-tailed maggot, blood worm.

Animals found in areas with high levels of oxygen - mayfly nymph, stonefly nymph, shrimp.