Topic 7a Organisms and Their Environment

Question 1

What is a community

Answer 1

The populations of different species living in a habitat

Question 2

What is an Ecosystem

Answer 2

The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment

Question 3

Name four resources which animals compete for

Answer 3

Territory
Food
Water
Mates/Partner

Question 4

What is a Habitat

Answer 4

Place where an organism lives

Question 5

What is a Population

Answer 5

All the organisms of one species living in a habitat

Question 6

What are the Abiotic factors of an environment

Answer 6

The non living factors of an environment:

• Water/moisture level
• Soil/ PH level and mineral content
• Sunlight/ Light intesity
• Temperature
• Air/ Oxygen or Carbon dioxide level

Question 7

What are the Biotic factors of an environment

Answer 7

The Biotic factors of an environment:

• Plants
• Animals
• Fungi
• Bacteria

Question 8

What is meant by a stable community

Answer 8

A stable community is a community where all species and environmental factors are in balance so that the population sizes are roughly constant (they MAY GO UP and down in cycles) examples are Tropical rain forests and ancient oak woodlands

Question 9

What are adaptions

Answer 9

The features or characteristics that allow organisms to live in specific environments.

Question 10

What are the three categories of adaptions

Answer 10

Structural = Features of an organisms body structure

Behavioural = Ways in which organisms behave e.g. migrating to a warmer environment during winter months

Functional adaptions = These are things that go on inside an organisms body that can be related to processes like reproduction or metabolism

Question 11

Give an example of a structural adaption an organism may have

Answer 11

Animals living in a hotter climate have a thinner layer of fat and a large surface area to volume ratio to help them lose heat

Arctic animals like the arctic fox have White coloured fur to help camouflage into the surrounding snow thus helping them to avoid predators as well as sneak up on prey

Question 12

Give an example of a functional adaption an organism may have

Answer 12

Brown bears hibernate over winter. They lower there metabolism which helps to conserve energy so they don’t have to when there is a lack of food available

Question 13

Give an example of Behavioural adaptions an organism may have

Answer 13

Swallows migrating to warmer climates during the winter to avoid the problems associated with living in colder conditions

Question 14

What is an Extremophile and give two examples of the conditions in which an extremophiles may live

Answer 14

An extremeophile is an organism that is adapted to living in extreme conditions. For instance Thermococcus is a form of bacteria which is adapted to survive and reproduce at extremely high temperatures (They live in deep sea hydrothermal vents)

Question 15

What is a food chain

Answer 15

A food chain shows what is eaten by what in an ecosystem

Question 16

Write down the basic order of organisms in a food chain

Answer 16

Producer - primary consumer - secondary consumer - TERRITORY CONSUMER

Question 17

What is a producer in regards to the food chain

Answer 17

• Producers are at the beginning of the food chain
• Producers make their own food using energy from the sun
• They are usually green plants or algae and produce glucose of which some is used to make biological molecules known as Bio mass (Mass of living material)

Question 18

The foloowing food cahin is observed in africa

Grass - Zebra - Chettah

1. Suggest the effect that an increase in grass would have on the population of cheetahs
2. After a certain amount of time the population of cheetahs would return to its normal level explain why

Answer 18

The population of any species is usually limited to the amount of food available. So if there is an increase in grass then there will be an increase in the amount of zebras as there is more grass for the zebras to feed on. This in turn will have an increase on the amount of cheetahs in the ecosystem as there will also be more zebras for the cheetahs to prey on.

As the cheetah population increases the zebra population will decrease because there are more cheetahs to eat them. This will lead to a decline in the cheetah population as there is not enough zebras to sustain there existence.

Question 19

What is meant by the distribution of an organism

Answer 19

The distribution of an organism refers to the specific place where an organism is found e.g. Its habitat maybe a playing field the distribution refers to a specific part f the playing field.

Question 20

What is a Quadrat and how can it be used to investigate the distribution of a species

Answer 20

A Quadrat is a square frame enclosing a known area e.g. a square 1m by 1m. It can be used to measure and compare how common an organism is in two sample areas e.g. shady and sunny part of a playing field usually plants or slow moving animals

Question 21

Describe how you would use random sampling with a quadrat to compare the distribution of organisms in two sample areas

Answer 21

1. Place the quadrat on the ground at a random position in the first sample area and count the amount of organisms within the quadrat
2. Repeat this many times
3. Repeat the whole process inn a 2nd sample area
4. Work out the mean number of organisms per quadrat in each sample area and compare the results

Question 22

What is a transect and how can it be used to measure the distribution of an organism

Answer 22

A transect is a line running across a given area where data is collected along the line in order to determine the distribution of organisms. This can be done by counting the organisms which touch the line or using quadrats placed along the line at specifc intervals.

Question 23

Give three environmental changes that can affect the distribution of an species

Answer 23

Availability of water - Distribution of animals changes between the wet and dry seasons e.g. wildebeest migrate moving north and back south as rainfall patterns change

Temperature - Distribution of bird species in Germany is changing because of a rise in the average temperature

Composition of atmospheric gases - Distribution of some species can change due to the amount of air pollution

Question 24

Give an example of three causes of environmental changes in distribution

Answer 24

Seasonal factors
Geographical factors
Human interaction

Question 25

Describe the water cycle

Answer 25

• Refers to the earths water being recycled
• Energy from sun makes water from land/sea/plants evaporate and turn into water vapour
• Water vapour is carried upwards where it reaches a certain point and cools/condolences to form clouds
• Water falls from the clouds as precipitation where it provides fresh water to the land.
• It drains into the sea and the whole process starts again

Question 26

How does C02 from the atmosphere first enter the food chain

Answer 26

Carbon dioxide is taken from the atmosphere by Green plants and algae (Photosynthesis) and used to make glucose which can be turned into fats, carbohydrates and proteins that make up the bodies of the plants and algae.

Question 27

How is C02 returned to the atmosphere from dead leaves

Answer 27

Dead leaves are fed on by microorganisms and animals known as Detritus feeders. These organisms release C02 when they respire. It can also be released back to the atmosphere through the burning of wood and fossil fuels (Combustion)

Question 28

A student said some water in trees eventually ends up in the sea, is the student right? explain your answer

Answer 28

Yes water evaporates from the tree during the Transpiration process and cools and condenses as it gets up higher. water falls from the clouds as precipitation onto the land. It the drains form the ground back into the sea.

Question 29

What is responsible for decay (Decomposition)

Answer 29

Microorganisms such as Bacteria Fungi and detritus feeders are responsible for decay and the breakdown of tissue

Question 30

What factors affect the rate of decay

Answer 30

Temperature - warmer temperatures increase the rate of decay as they increase the rate that enzymes involved in decomposition work at. If its too hot decomposition will slow down or stop because those enzymes are destroyed. Extreme cold slows the rate of decomposition

Oxygen availability - Many organisms need oxygen to respire which is essential to there survival.

Water availability - Decay takes place faster in moist environments because organisms involved in the decaying process need water to carry out biological processes.

Number of decay organisms - The more microorganisms and detritus feeders there are the faster decomposition will occur

Question 31

Compost is the decayed remains of animals and plant matter. Why is compost used on gardens

Answer 31

It acts as a natural fertiliser for crops and garden plants by recycling nutrients back into the soil

Question 32

What is Bio gas

Answer 32

Bio gas is a mixture of gases mainly consisting of Methane which is produced by the breakdown of organic matter Anaerobically (without oxygen). Lots of organisms are used to create bio gas, they decay plant material and animal waste producing methane gas.

Question 33

What are the two main types of Bio gas Generators

Answer 33

Batch Generator - These make Bio gas in small batches and are manually loaded up with waste which is left to digest with the by products of digestion cleared away at the end of each session.
They don’t make bio gas at a steady rate

Continuous generators - Makes bio gas all the time with waste being continuously fed into the generator.
They are more suited to large scale bio gas projects

Question 34

In an experiment analysing the distribution of organisms in a given area, why are quadrats placed randomly

Answer 34

To increase the validity of the results

Question 35

What are the following:
Habitat
Community 
Ecosystem 
Population

Answer 35

Habitat = Place where organisms live 
Community = Different species living in a Habitat
Population = All Organisms of the same species living in a Habitat 
Ecosystem = The interaction of Living organisms with the non living parts of their environment