Populations and ecosystems A01

Question 1

Habitat and niche

Answer 1

Place an animal lives vs role an organisms plays

Question 2

Biotic and abiotic

Answer 2

Living vs non-living factors

Question 3

Population and community

Answer 3

a group of individuals of the same species living within an area vs an interacting group of various species in a common location.

Question 4

Ecology and ecosystem

Answer 4

Study of the relationships between living organisms vs a community of living organisms in a particular area.

Question 5

List 4 factors that affect how large a population is

Answer 5

Birth rate, death rate, emigration and immigration

Question 6

Using the letters B,D,E and I write an equation for a stable population

Answer 6

B+ I= D +E

Question 7

What will happen to the size of the population if the birth rate exceeds death rate?

Answer 7

Increase

Question 8

Why is it not appropriate to use the term “birth” for populations of single-celled organisms like yeast, bacteria and paramecium? What term might be more appropriate?

Answer 8

They produce individuals using binary fission.

Question 9

State a factor that could slow the population growth and one that could cause a population crash.

Answer 9

Food or nutrient limitation and a forest fire

Question 10

What is meant by the term “carrying capacity”?

Answer 10

Carrying capacity is the maximum number of individuals of a species that an environment can support.

Question 11

Define density dependent

Answer 11

any force that affects the size of a population of living things in response to the density of the population.

Question 12

Define density independent

Answer 12

Any force that affects the size of a population of living things regardless of the density of the population.

Question 13

Name two density dependent factors and two density independent factors.

Answer 13

Disease, competition and predation
And
Food or nutrient limitation, pollutants in the environment, and climate extremes.

Question 14

The fall in living bacteria is because they have been heated. Is this a density dependent or independent factor?

Answer 14

Density independent

Question 15

What is the advantage of using log values when graphing populations of bacteria?

Answer 15

Let’s you identify a pattern when there are large value changes

Question 16

What type of sampling would you use to investigate an area with an ecological gradient?

Answer 16

Line/belt transect

Question 17

Describe how you would carry out an investigation of an area’s ecological gradient

Answer 17

Placing a measuring tape along the shore line then placing a quadrat at different distances along this line and recording the species and their numbers.

Question 18

How could you present the data for an ecological gradient?

Answer 18

Kite diagram

Question 19

Which type of sampling would you use to investigate the effect of aspect on two sides of a hill?

Answer 19

Quadrat sampling

Question 20

Describe how you would carry out an investigation for the effect of aspects on two sides of a hill

Answer 20

Place two measuring tapes across an area like two axes of a graph. Then use a telephone number or a random number generator to make random coordinates. Place the quadrants in the random area.

Question 21

What calculation could you perform to assess the biodiversity in two areas?

Answer 21

Simpsons diversity

Question 22

What data would you need to collect to perform the calculation?

Answer 22

Number of individual species in each area.

Question 23

How could you improve the reliability of the data?

Answer 23

Use more Quadrat samples

Question 24

What is the source of energy for most ecosystems?

Answer 24

Light

Question 25

Define GPP

Answer 25

The amount of chemical energy which is created from light energy in a given amount of time.

Question 26

Define NPP

Answer 26

The chemical energy stored in plant biomass after respiratory losses.

Question 27

Write an equation to illustrate the relationship between NPP and GPP

Answer 27

NPP= GPP- R

Question 28

How is energy “lost” from each trophic level?

Answer 28

90 % of energy may be lost as heat (released during respiration), through movement, or in materials that the consumer does not digests.

Question 29

Define succession

Answer 29

The process by which the mix of species and habitat in an area changes over time.

Question 30

What is a seral stage?

Answer 30

A stage in succession

Question 31

Name the seral stages for a primary succession starting with bare rock.

Answer 31

Pioneer species through to climax communities

Question 32

What is the role of immigration in succession?

Answer 32

The presence of an initial species aids and increases the probability of the growth of a second species.

Question 33

What happens to species diversity and the stability of ecosystems as a succession progresses?

Answer 33

Both increase

Question 34

What is the difference between primary and secondary succession?

Answer 34

Primary succession occurs in an environment without previous life, or barren habitat. Secondary succession occurs in an area that had previously been inhabited but experienced disturbance.

Question 35

What would be the independent variable in an investigation into succession?

Answer 35

Time

Question 36

How would you carry out an investigation into succession?

Answer 36

Observe/record species over time

Question 37

What would you “measure” in an investigation into succession?

Answer 37

Number of individuals in each species

Question 38

What is the role of detritivores in an ecosystem?

Answer 38

Break down dead organic matter

Question 39

What modes of nutrition do detritivores have?

Answer 39

Heterotrophic- holozoic

Question 40

What is the role of plants in nutrient cycling?

Answer 40

Absorb nutrients from soil so that they can re-enter the food chain.

Question 41

Why do plants need the following: nitrates, phosphates, sulphate and carbon dioxide?

Answer 41

Nitrates- plant protein phosphates- need to make DNA from cell membranes Sulphate- plant protein formation Carbon dioxide- photosynthesis

Question 42

How are mineral ions absorbed into root hairs?

Answer 42

Active transport

Question 43

How do mineral ions get transported throughout the plants?

Answer 43

Up the xylem dissolved in water

Question 44

By what process is carbon dioxide removed from air by plants?

Answer 44

Photosynthesis

Question 45

Give the names of two processes that return carbon dioxide to the atmosphere

Answer 45

Combustion and respiration

Question 46

Explain two human activities that increase global carbon dioxide levels

Answer 46

Burning fossil fuels and deforestation

Question 47

Explain why increasing carbon dioxide levels are increasing global temperatures

Answer 47

Carbon dioxide is a greenhouse gas

Question 48

Define carbon footprint

Answer 48

The total amount of greenhouse gases (including carbon dioxide and methane) that are generated by our actions.

Question 49

Explain why humans should do the following to halt climate change: Not fly

Answer 49

Reduces fossil fuel use

Question 50

Explain why humans should do the following to halt climate change: Not drive

Answer 50

Reduce fossil fuel use

Question 51

Explain why humans should do the following to halt climate change: Reduce electricity use

Answer 51

Reduce fossil fuel use

Question 52

Explain why humans should do the following to halt climate change: Be vegan

Answer 52

More energy is needed to produce meat

Question 53

Explain why humans should do the following to halt climate change: Buy locally produced groceries in season

Answer 53

Reduce fossil fuel use in transporting produce

Question 54

What is a planetary boundary?

Answer 54

A framework to describe limits to the impact of human activities on the Earth System

Question 55

Outline the effects of crossing the planetary boundary for carbon dioxide on land and in the oceans.

Answer 55

Land- flooding and extreme weather patterns, mass extinction. Ocean- Acidification, mass extinction

Question 56

What does “nitrogen is an inert gas” mean?

Answer 56

Nitrogen is unreactive

Question 57

What is the process of nitrogen fixation?

Answer 57

Any natural or industrial process that causes free nitrogen (N2) to combine chemically with other elements to form more-reactive nitrogen compounds such as ammonia, nitrates, or nitrites

Question 58

Name the nitrogen- fixing bacteria that are free-living in soil.

Answer 58

Azotobacter

Question 59

How do they maintain the aerobic conditions needed for nitrogen fixation?

Answer 59

Ploughing soil and draining fields

Question 60

Name the nitrogen-fixing bacteria that live in legume root nodules

Answer 60

Rhizobium.

Question 61

Why is the relationship between Rhizobium and legume root nodules symbiotic?

Answer 61

Both organisms benefit

Question 62

What is the function of Leghaemoglobin?

Answer 62

Molecule that Rhizobium use to obtain oxygen

Question 63

What do fungi and bacteria convert amino acids and urea to in the process of decomposition?

Answer 63

Ammonia

Question 64

Describe both steps in nitrification, naming the bacteria that do each step.

Answer 64

Ammonium to Nitrites by Nitrosomonas and Nitrites to Nitrates by Nitrobacter.

Question 65

Is nitrification an aerobic or anaerobic process?

Answer 65

Aerobic

Question 66

What is the impact of waterlogging on nitrification?

Answer 66

Decrease nitrification

Question 67

What is denitrification?

Answer 67

Conversion of nitrogen containing compounds into atmospheric nitrogen.

Question 68

Under what conditions does denitrification take place?

Answer 68

Anaerobic

Question 69

What is the impact of water logging on nitrate levels of soil?

Answer 69

Oxygen levels of soil are reduced

Question 70

How would ploughing and draining fields increase nitrate levels in soil?

Answer 70

Creates aerobic conditions allowing nitrifying bacteria to survive

Question 71

Why are fertilisers applied to farmland?

Answer 71

Increase crop yield

Question 72

What are the benefits and drawbacks of inorganic fertilisers?

Answer 72

You can carefully manage the amount of each nutrient and it’s concentration- require a lot of energy to synthesise

Question 73

What are the benefits and drawbacks of organic fertilisers?

Answer 73

Can’t control the specific nutrient concentrations but are natural and require no extra energy input to obtain

Question 74

What is leaching?

Answer 74

Excess water removes water- soluble nutrients out of the soil, by runoff or drainage.

Question 75

Describe the process of Eutrophication

Answer 75

1. Increased nitrates in the water increase the growth of algae and plants. 2. The algae from a bloom over the water surface, preventing sunlight reaching other water plants 3. These plants die because unable to carry out photosynthesis without light. 4. Microbes such as bacteria increase in number as they feed off the dead plants, using and reducing the oxygen content in the water during respiration as they do so. 5. The low oxygen levels can cause aquatic insects and fish to suffocate, eventually the lake may be left completely lifeless.

Question 76

Wildflowers grow on nutrient poor soils, how does the use of fertilisers impact species diversity?

Answer 76

Wildflowers cannot survive if fertilisers are applied and therefore species diversity is reduced.