Life On Earth test

Question 1

Abiotic factors

Answer 1

(Non - living factors) -ph, temperature, soil moisture, humidity, rainfall, light intensity

Question 2

Biotic factors

Answer 2

(Factors linked to living things) -grazing, predation, food availability, disease, competition

Question 3

Direction of energy flow

Answer 3

Producer (plant) ➡️ primary consumer (herbivore) ➡️ secondary consumer (omnivore/carnivore) ➡️ tertiary consumer (top carnivore)

Question 4

Niche

Answer 4

A niche is the role that an organism plays within a community

Question 5

Interspecific competition

Answer 5

Interspecific competition occurs amongst individuals of different species for one or a few resources they require

Question 6

Interspecific competition

Answer 6

Intraspecific competition occurs amongst individuals of the same species and is for all resources required. It is therefore more intense competition than Interspecific

Question 7

Photosynthesis word equation

Answer 7

Carbon dioxide + water, arrow with light energy above arrow and chlorophyll bellow arrow, then glucose + water

Question 8

Stages of photosynthesis

Answer 8

Stage 1 photolysis OR KNOWN AS light reactions
Stage 2 carbon fixations

Question 9

Stage 1 photosynthesis diagram

Answer 9

Draw on whiteboard

Question 10

Stage 2 photosynthesis diagram

Answer 10

Draw on whiteboard

Question 11

Uses of sugar in photosynthesis

Answer 11

1. Respiration
2. Structural carbohydrate (used for cell walls) = cellulose
3. Converted into storage carbohydrate = starch

Question 12

Limiting factors

Answer 12

1. Light intensity
2. Carbon dioxide concentration
3. Temperature

Question 13

Limiting factor graphs

Answer 13

Do some examples

Question 14

Paired statement key

Answer 14

Do some examples

Question 15

How is energy lost in food chains

Answer 15

1. Heat
2. Movement
3. Un digested waste

Question 16

Pyramid of numbers

Answer 16

Shows total number of organisms at each stage in a food chain
- Draw one for grass, rabbit, fox
- isn’t always a pyramid shape
- eg draw oak tree, greenfly, ladybird, small bird.

Question 17

Pyramid of energy

Answer 17

Shows energy available at each stage of food chain
- always pyramid shaped
- goes produces, primary consumer, secondary consumer

Question 18

Food yield

Answer 18

An increased food yield is required due to the increased human population

Question 19

Pesticides

Answer 19

The use of pesticides to kill plants and animals deciding crop yield
- some pesticides are not biodegradable and result in remaining in soil/rivers/lochs for a long time and will build up in body’s of organisms over time. These toxins are passed along food chains so when one organism eats an intoxiniated animal it will increase there toxicity. This is called bioaccumulation
- ddt is a lethal example of bioaccumulation

Question 20

The nitrogen cycle

Answer 20

Draw this

Question 21

Leaching

Answer 21

The fertiliser added to an area can run off in nearby body’s of water. This increases nitrate levels and algsl bloom forms, blocking light and killing any green plants. When the water cannot sustain such a large algae population it dies. The dead algae provides a huge food dource for bacteria. The bacteria reduces huge amounts of oxygen killing any left over organisms

Question 22

Fertilisers

Answer 22

Fertilisers are added to land to increase the levels of essential plant nutrients that are used up by the growing plants/crops and not replaced by natural nutrient cycling due to the removal of the crop. So farmers ass nitrogen to the soil in the form of synthetic fertiliser, manure or compost.

Question 23

Biological control

Answer 23

Biological control can be used as an alternative method to pesticide. This involves the introduction of a predator to prey on a pest species. An example of a biological control is using ladybirds to control greenfly populations.

Question 24

Gm crops

Answer 24

Genetically modified crops are crops which have had their genome altered. This change can enable the crop to produce a chemical that is harmful to the pest but should not be harmful to humans, there has however been some controversy over the use of gm crops

Question 25

Mutation

Answer 25

Mutations are caused by a random change to an organisms genetic material.

Environmental factor such as radiation or chemicals can increase mutation rate

Question 26

Natural selection

Answer 26

New alleles produced by mutation can result in plants and animals becoming better adapted to their environment. As the environment changes constantly variation allows a population to evolve over time in response to the change.

This is also known as survival of the fittest

Question 27

Speciation

Answer 27

-population to interbreed freely
-barrier placed
-different mutations occur in each sub population
- natural selection occurs within the sub populations
-each sub population evolves until even the barrier is removed, the sub populations can no longer breed to produce fertile offspring - speciation has occurred

Question 28

Isolating mechanisms

Answer 28

The isolating mechanisms or barriers that split a population can be geographical (mountains/rivers) THE EXAMPLE TO USE IN EXAM IS GEOGRAPHICAL, behavioural (differences in rituals ie breeding calls or mating dances) or ecological (different habitats, PH or salinity