Unit 3

Question 1

What is a niche?

Answer 1

The role an organism plays within a community

Question 2

What are the factors that determines an organisms niche?

Answer 2

Habitat, feeding level, when active, interaction with other organisms

Question 3

What are biotic factors?

Answer 3

Factors related to living things

Question 4

What are abiotic factors?

Answer 4

Non-living or physical factors

Question 5

Give an example of a biotic factor

Answer 5

Competition for food, space, mates. Number of predators. Disease. Grazing

Question 6

Give an example of abiotic factors

Answer 6

Temperature, humidity, pH, light intensity, rainfall, wind

Question 7

What could over grazing lead to?

Answer 7

Plant species being destroyed

Question 8

What is predation?

Answer 8

The eating of one organism from another

Question 9

What do predators keep down the numbers of?

Answer 9

Their prey

Question 10

What is biomes?

Answer 10

The different regions of our planet as distinguished by their similar climate, fauna and flora

Question 11

What can biomes be influenced by?

Answer 11

Temperature and rainfall

Question 12

How can energy be lost in an ecosystem?

Answer 12

Heat movement, trapped in waste

Question 13

In a food chain how much of the energy is lost between each animal?

Answer 13

90%

Question 14

When an animal or plant dies what breaks it down?

Answer 14

Decomposers

Question 15

What is a pyramid of biomass?

Answer 15

Represents the mass of each feeding level in a food chain

Question 16

Which type of pyramid is the most accurate?

Answer 16

Pyramid of energy

Question 17

Why do living things need nitrogen?

Answer 17

To form proteins

Question 18

What can farmers do if the soil is low in nitrates?

Answer 18

They add it in the form of fertilisers

Question 19

What is nitrification?

Answer 19

Bacteria converting ammonium compounds into nitrites then nitrates

Question 20

What is denitrification?

Answer 20

Bacteria deprived soil of nitrogen by releasing gas into the air

Question 21

What is nitrogen fixation?

Answer 21

Bacteria absorb and ‘fix’ nitrogen into nitrates for plants to absorb

Question 22

What is intra specific competition?

Answer 22

Competition between members of the same species

Question 23

What is the definition of a community?

Answer 23

All living things in an ecosystem

Question 24

What is inter specific competition?

Answer 24

Competition between members of different species

Question 25

What does competition help prevent?

Answer 25

Population of animal and plants becoming too large

Question 26

What can competition be for?

Answer 26

Space, mates, food, water, light, shelter

Question 27

What would plant in a large forest compete for?

Answer 27

Light, water, CO2, nutrients

Question 28

Name two sampling techniques for biotic factors

Answer 28

Quadrat and pitfall trap

Question 29

How does a quadrat work?

Answer 29

Laid out randomly on ground, plants and animals are counted

Question 30

How does a pitfall trap work?

Answer 30

Animals fall into container

Question 31

What is a pitfall trap for?

Answer 31

Sampling surface living animals

Question 32

Why must samples be completely random?

Answer 32

To avoid any bias. Truly representative of the whole area being studied

Question 33

How could you make your sampling technique more accurate?

Answer 33

Use better apparatus

Question 34

How could you make your sampling technique more reliable?

Answer 34

Take more samples

Question 35

What could be used to measure light intensity?

Answer 35

A light meter

Question 36

A combined meter is used to measure what?

Answer 36

The water content and pH of soil

Question 37

What do you have to do when using a combined meter?

Answer 37

Push probe to same depth and always clean between readings

Question 38

What is a limitation of a pitfall trap?

Answer 38

Sample obtained may not be representative of the whole area

Question 39

How could you prevent animals eating each other in a pitfall trap?

Answer 39

Don't leave traps fro long periods of time before emptying

Question 40

What are mutations?

Answer 40

Changes which alter the amount or structure of the genetic material in an organism

Question 41

Do environmental factors increase or decrease the rate at which mutations occur?

Answer 41

Increase

Question 42

What are environmental factors affecting mutations called?

Answer 42

Mutagenic agents

Question 43

What can mutations result in for the organism?

Answer 43

An advantage or disadvantage (usually a disadvantage)

Question 44

What type of mutation has no effect on an organism?

Answer 44

A neutral mutation

Question 45

All members of a population shows what?

Answer 45

Variation

Question 46

Without variation what would not be possible?

Answer 46

Evolution

Question 47

What is adaption

Answer 47

A variation that makes an organism more likely to survive in its niche

Question 48

When does natural selection occur?

Answer 48

When there are more animals than the environment can sustain

Question 49

What is a species?

Answer 49

Organisms that can interbreed and produce fertile offspring

Question 50

What is speciation?

Answer 50

The formation of a new species

Question 51

What are the three types of isolation barriers?

Answer 51

Geographical, ecological, reproductive

Question 52

What is being used to increase food yield?

Answer 52

Intensive farming

Question 53

What are some of the things used in intensive farming?

Answer 53

Chemical fertilisers and pesticides, animals kept inside, competing plants removed

Question 54

What is the definition of monoculture farming?

Answer 54

Growing a single crop over a large area

Question 55

What are some advantages of monoculture?

Answer 55

Allows for more than one harvest per year, reduced labour costs

Question 56

What are some disadvantages of monoculture?

Answer 56

Higher risk of disease, requires lots of fertilisers, biodiversity decreases

Question 57

What are chemical fertilisers?

Answer 57

Chemicals added to soil to improve plant growth

Question 58

What minerals are important to plant growth?

Answer 58

Nitrates and magnesium

Question 59

What forms when fertilisers leach into fresh water?

Answer 59

Algal blooms

Question 60

What are some of the impacts of algal blooms in fresh water?

Answer 60

Less light reaches plants, plant unable to photosynthesis, therefore reduction in oxygen levels in water

Question 61

What are pesticides?

Answer 61

Chemicals sprayed onto crops to reduce completion from other organisms

Question 62

What are the four types of pesticides?

Answer 62

Herbicides, fungicides, insecticides and bactericides

Question 63

Why do pesticides have a negative effect on biodiversity?

Answer 63

Pesticides can accumulate in the bodies of organisms over time

Question 64

What is bioaccumulation?

Answer 64

As you get higher up the food chai, the level of pesticides increases

Question 65

As pesticides go up the food chain what increases?

Answer 65

Toxicity

Question 66

What is biological control?

Answer 66

When a natural predator in introduced and it feeds on the pest

Question 67

What is an alternative to using pesticides?

Answer 67

Biological control

Question 68

Why is biodiversity a good alternative to using pesticides?

Answer 68

It is a cheaper method, natural and biodiversity is not reduced

Question 69

What can cause harm to an ecosystem?

Answer 69

Pollution

Question 70

What is an indicator species?

Answer 70

By its presence, absence or abundance shows the environmental conditions

Question 71

What does the indicator species 'fresh water invertebrates' show?

Answer 71

Levels of pollution in fresh water

Question 72

What does the indicator species 'lichen' show?

Answer 72

Levels of air pollution