Biology PMT unit 4

Define population

A group of of organisms of the same species living in an area at one time

Define Community

When different populations interact in the same habitat

Define habitat

The place where a living organism lives

Define ecosystem

The interaction of a community with the biotic and abiotic parts of its environment

How can we predict the population size of an organism in an area?

• C - Quadrants should be placed randomly

• O - Count the number of the target species in each square of the quadrant

• R - Repeat with multiple quadrants

• M - Calculate the mean percentage

• S - Ensure that through out the investigation, the size of the quadrant remains constant and the day the data was collected

What are abiotic factors?

Non-living components of an ecosystem

Give some examples of abiotic factors

• Water

• Sunlight

• Temperature

• Soil

• Air

• Wind

• Humidity

• pH

How do abiotic factors affect organisms?

They influence:

• Growth

• Survival

What are biotic factors?

Living components of an ecosystem

Give some examples of biotic factors

• Plants

• Animals

• Bacteria

• Fungi

How do biotic factors affect the environment?

They influence:

• Competition

• Predation

• Disease

List the order of trophies level of an ecosystem

Producer → Primary consumer → Secondary consumer → Tertiary consumer → Quaternary consumer

Draw a pyramid for the food chain:

grass → snail → frog → wolf

Biomass (kg): 1450 → 138 → 14.1 → 1.18

Calculate the efficiency of biomass transfer from the first to second trophies level. Give your answer to 3sf.

(138 / 1450) x 100 = 9.52%

Describe the carbon cycle

• Carbon in fossil fuels (in the form of coal and oil) are combusted in factories

• Carbon is released into the atmosphere

• The Carbon reacts with oxygen to form Carbondioxide

• CO2 is used up in photosynthesis to produce glucose

• Plants are eaten by animals

• The animals:

  • Respire (breathe) to release CO2 into the atmosphere

  • OR carbon is lost by excretion

• The waste products of animals are decomposed and form fossil fuels in the earth

Describe the formation of acid rain

• Sulfur is a component in fossil fuels

• When they are burned, sulfur dioxide is released which can cause respiratory problems

• Sulfurdioxide is absorbed by water vapour to form acid rain

How is acid rain harmful to the environment?

• It can make rivers too acidic, killing aquatic organisms

• It corrodes limestones in statues and infrastructures

• It leeches minerals out of soil, plants and trees cannot survive

How does Carbon Monoxide affect the human body?

• Released when fossil fuels are burned

• It binds with haemoglobin which reduces the blood’s ability to carry oxygen

• This can lead to tiredness, unconsciousness and even death

• In pregnant women, this can effect the growth of the fetus

What is a greenhouse gas?

Gases that absorb radiation from the sun and traps it at earth’s surface (aka greenhouse effect), causing the temperature to rise (global warming)

What human activities release greenhouse gases?

• Burning fossil fuels

• Livestock farming

• Deforestation

What are the environmental effects of global warming?

• Climate change

• Water levels rising because glaciers melt from high temperatures

• Loss of habitats so some species will become extinct

Describe how algal bloom occurs in sewage

• Sewage flows into water bodies

• Sewage is rich in minerals and nutrients so decomposes and algae thrive

• Decomposes respire aerobially to break down sewage, which uses oxygen but some bacteria in might respire anaerobically

• The algae will grow dramatically, causing algal bloom

What are the affects of algal bloom?

• It stops light from reaching aquatic organisms so they die, plants cannot conduct photosynthesise and fish will not receive oxygen (oxygen deprecation) and die

What is eutrophication?

When fertilisers are washed off land into waterbodies by the rain