Life on earth Flashcards

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1
Q

Definition of species

A

A group of organisms that are able to interbreed to produce fertile offspring of a similar type

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2
Q

Definition of biodiversity

A

the variety and abundance of living organism found in a particular area

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3
Q

Definition of population

A

the number of individuals of one species found in an area

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4
Q

Definition of producers

A

green plants that can produce food by the process of photosynthesis

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5
Q

Definition of consumer

A

consumers eat other organisms to obtain energy

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6
Q

definition of herbivore

A

A consumer that only eats plants to obtain energy

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7
Q

Definition of carnivore

A

only eat other animals to obtain energy

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8
Q

Definition of omnivore

A

consumers that eat both animals and plants to obtain energy

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9
Q

Definition of predator

A

consumers that kill other animals to eat

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10
Q

Definition of prey

A

Species that ate killed by other consumers

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11
Q

Definition of food chain

A

a sequence of organisms through which energy flows when one organism eats another

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12
Q

Definition of food web

A

Shows the numerous paths that energy can take as it flows through the species in an ecosystem

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13
Q

What is an ecosystem

A

An ecosystem consists of all the organisms living in a particular habitat and the non living components which these organism interact

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14
Q

What does a food web show

A

The feeding interactions within a food web using arrows to show the direction of energy flow which indicates which species are feeding on which as the energy moves from prey to predators

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15
Q

What do food webs also reveal

A

Competitive interactions within a food web

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16
Q

What is the effect on a food web if a prey species is removed

A

It’s predators will decline in population

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17
Q

What is the effect on a food web if a predator species is removed

A

It’s prey species will become more common

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18
Q

What is a niche

A

A role that an organism plays within a community

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19
Q

What does a niche relate to

A

the resources an organism requires in its ecosystem, such as light and nutrient availability, and its interactions with other organisms in the community

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20
Q

What does niche involve

A

competition and predation and the conditions an organism can tolerate, such as temperature

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21
Q

When does competition in ecosystems occur

A

When resources are in short supply

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22
Q

Does interspecific competition occur between the same species or different species

A

Different

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23
Q

Does intraspecific competition occur between the same species or different species

A

Same

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24
Q

What is more intense interspecific competition or intraspecific competition

A

Intraspecific

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25
Q

Where is the majority of energy lost in transfer from one level to the next on a food chain

A

as heat, movement or undigested materials

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26
Q

Definition of a pyramid of numbers

A

Pyramid of numbers show the total number of individual organisms at each level in the food chain of an ecosystem

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27
Q

Definition of a pyramid of energy

A

A pyramid of energy shows the total quantity of available energy stored in the organisms at each level in the food chain of an ecosystem per year

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28
Q

What are true pyramids of energy

A

Irregular shapes of pyramids of numbers based on different body sizes

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29
Q

What does the increasing human population require

A

Increasing food yield

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30
Q

What can this involve

A

The use of fertilisers or pesticides

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31
Q

What do fertilisers do

A

provide chemicals such as nitrates, which increase crop yield

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32
Q

What do pesticides do

A

Kill plants or animals that reduce crop yield

33
Q

What are nitrates that are absorbed into soil water also absorbed into

A

Plants

34
Q

What are nitrates used for

A

produce amino acids which are synthesised into plant proteins

35
Q

Why do animals consume plants or other animals

A

To obtain amino acids for protein synthesis

36
Q

What do fertilisers do when added to soil

A

Increase the nitrate rate

37
Q

What do fertilisers do if they leach into fresh water

A

Add extra unwanted nitrates

38
Q

What do these nitrates increase

A

Algal population which can cause algae blooms

39
Q

What do alga, blooms do

A

reduce light levels, killing aquatic plants

40
Q

What does these dead plants become

A

Food for bacteria which greatly increase in number

41
Q

What does this bacteria use up

A

large quantities of oxygen, reducing the oxygen availability for other organisms

42
Q

What can be used to reduce the use of fertilisers

A

Genetically modified crops

43
Q

When pesticides are sprayed onto crops what can happen

A

They can accumulate in to bodies of plants over time

44
Q

What is bioaccumulation

A

The build-up of toxic substances in living organisms

45
Q

What happens when pesticides are passed along food chains

A

toxicity increases and can reach lethal levels

46
Q

What can be used as alternatives to pesticides

A

Biological control and genetically modified crops

47
Q

What is a mutation

A

A random change in genetic material

48
Q

Are mutations only a disadvantage to survival

A

Now they can be an advantage and neutral as well

49
Q

What are mutations the only source of

A

New alleles

50
Q

What can increase the rate of mutation

A

Environmental factors such as radiation and some chemicals

51
Q

What can new alleles result in

A

Plants and animals being better adapted to their environment

52
Q

What does variation in a population make possible

A

a population to evolve over time in response to changing environmental conditions

53
Q

What is an adaption

A

an inherited characteristic that makes an organism well suited to survival in its environment/niche

54
Q

When does natural selection occur

A

When there are selection pressures

55
Q

What type of individuals survive natural selection

A

The best adapted

56
Q

What do these surviving individuals do

A

Reproduce sending on favourable alleles that confer the advantage

57
Q

What do these alleles do

A

Increase in frequency in the population

58
Q

When does speciation occur

A

after part of a population becomes isolated by an isolation barrier, which can be geographical, ecological or behavioural

59
Q

How does natural selection work

A

selects for different mutations in each group, due to different selection pressures

60
Q

What are the two stages of photosynthesis

A

Light reactions and carbon fixation

61
Q

What is the light reaction

A

The light energy from the sun is trapped by chlorophyll in the chloroplasts and is converted into chemical energy which is used to generate ATP. Water is split to produce hyrdrogen and oxygen. oxygen diffuses from the cell. The hydrogen and ATP are required for the next stage of carbon photosynthesis.

62
Q

What is carbon fixation

A

A series of enzyme-controlled reactions, which use hydrogen and ATP (produced by the light reactions) with carbon dioxide to produce sugar.

63
Q

What is the sugar that is produced by photosynthesis used for

A

Respiration, stored as starch and to make carbohydrate cellulose

64
Q

What are the limit g factors of photosynthesis

A

Carbon dioxide concentration, light intensity and temperature

65
Q

What is the carbon dioxide concentration impact on photosynthesis

A

Carbon dioxide is required during the carbon fixation stage of photosynthesis to make sugar

66
Q

What is the light intensity impact on photosynthesis

A

Light is required to provide energy for the light reactions - without these there will be no ATP or hydrogen to pass to carbon fixation.

67
Q

What is the temperatures impact on photosynthesis

A

the temperature affects the rate that the enzymes that are responsible for catalysing the reactions in both stages can occur.

68
Q

What are biotic factors

A

Competition for resources, disease, food availability

69
Q

What are abiotic factors

A

Light intensity, moisture, Ph and temperature

70
Q

What measures light intensity

A

Light meter

71
Q

What measures temperature

A

thermometer

72
Q

What measures soil ph

A

soil ph meter

73
Q

What measures soil moisture

A

soil moisture meter

74
Q

What can cause error with light intensity and how do you minimise it

A

Casting shadows by accident over the meter ensure that you do not stand near it

75
Q

What can cause error with temperature and how do you minimise it

A

Refrain from touching then end of the thermometer as this will effect the reading

76
Q

what can cause error with soil ph and how do you minimise it

A

The meter must be wiped clean between each measurement otherwise the ph might be similar to the before measurement

77
Q

What can cause error with soil moisture and how do you minimise it

A

same as soil ph

78
Q

What are indicator species

A

Species that by their presence/absence indicate environmental quality/levels of pollution