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Biology > Life on Earth - 3.1, 3.4, 3.5, 3.6 > Flashcards

Life on Earth - 3.1, 3.4, 3.5, 3.6 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is the definition of a species?

A

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

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2
Q

What is the definition of biodiversity?

A

Biodiversity is the variety and abundance of living organisms found in a particular area.

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3
Q

What is the definition of a population?

A

A population is the number of individuals of one species found in an area.

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4
Q

What happens if two members of the same species breed together?

A

they produce offspring of that species

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5
Q

What happens if two different species breed together?

A

The offspring are called hybrids and are less fertile and sterile.

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6
Q

What is the definition of a producer?

A

Producers are green plants that can produce their own food by the process of photosynthesis.

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7
Q

What is a consumer?

A

Consumers eat other organisms to obtain energy.

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8
Q

What is the definition of a herbivore?

A

A consumer that only eats plants to obtain energy. Herbivores can also be referred to as primary consumers.

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9
Q

What is the definition of a carnivore?

A

A consumer that only eats other animals to obtain energy.

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10
Q

What is the definition of an omnivore?

A

A consumer that eat both animals and plants to obtain energy.

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11
Q

What is the definition of a predator?

A

Predators are consumers that kill other animals to eat.

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12
Q

What is the definition of prey?

A

Prey species are those that are killed by other consumers.

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13
Q

What is the definition of a food chain?

A

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

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14
Q

What do the arrows in a food chain represent?

A

The direction of energy flow through different feeding levels in an ecosystem.

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15
Q

Describe a food chain.

A

The chain starts at a base with a producer and then energy flows to one primary consumer species, one secondary consumer species, one tertiary consumer species and so on.

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16
Q

What is a food web?

A

A food web shows the numerous paths that energy can take as it flows through the species in an ecosystem. All of the food chains are combined.

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17
Q

What does a food web make clear?

A

The organisms tend to be placed so that it is clear whether they are one of the producers at the base or in one of the layers of consumers further up.

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18
Q

What does an ecosystem consist of?

A

all the organisms living in a particular habitat and the non-living components with which the organisms interact.

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19
Q

What does the term community refer to?

A

All of the individuals of all of the species in an area.

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20
Q

What is a habitat?

A

The location or zone where an organism lives.

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21
Q

What does a food web show?

A

The feeding interactions.

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22
Q

What do the arrows in a food web indicate?

A

which species are feeding on which as the energy moves from the prey to the predators.

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23
Q

What do food webs reveal?

A

Competitive interactions within a food web.

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24
Q

What does a food web allow us to predict?

A

The impact of removing one species from the food web.

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25
Q

What happens if a prey species is removed from a food web?

A

Its predators will decline in population.
Alternative prey species may also decline in population as the predators will be forced to feed on them more than previously.

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26
Q

What happens if a predator species is removed from a food web?

A

It’s prey species will become more common.
This may mean that other predators that were in competition with the first species become more common as a result.

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27
Q

What is a niche?

A

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

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28
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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29
Q

What does niche involve?

A

Competition and predation and the conditions that an organism can tolerate, such as temperature.

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30
Q

When does competition in ecosystems occur?

A

When resources are in short supply.

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31
Q

Who does interspecific competition occur amongst?

A

Individuals of different species for one or a few of the resources they require.

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32
Q

What does the increasing human population require?

A

An increased food yield.

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33
Q

Why is the human population increasing?

A

The birth rate is higher than the death rate.

34
Q

How can we increase the food yield?

A

We can use fertilisers and pesticides.

35
Q

What are pests?

A

Plants and animals that reduce crop yield.

36
Q

How can pests be killed?

A

With pesticides.

37
Q

What does killing pests do to the food yield?

A

It increases the food yield as it reduces the amount of food that goes to pests.

38
Q

What do fertilisers produce?

A

Provide chemicals such as nitrates, which increase crop yield.

39
Q

What happens to nitrates dissolved in soil water?

A

They are absorbed into plants.

40
Q

What are nitrates used to produce?

A

Amino acids which are synthesised into plant proteins.

41
Q

Why do animals consume plants or other animals?

A

To obtain amino acids for protein synthesis.

42
Q

Why would fertilisers be added to soil?

A

To increase the nitrate content of the soil.

43
Q

What do fertilisers leaching into fresh water do to the water?

A

Adds extra, unwanted nitrates.

44
Q

What does leaching mean?

A

Leaching means nitrates have been washed by the rain from the soil into rivers or lakes.

45
Q

What will fertilisers leaching into fresh water increase?

A

Algal populations which can cause algal blooms.

46
Q

What do algal blooms do?

A

They reduce light levels which kills aquatic plants.

47
Q

What do these dead plants and dead algae become?

A

Food for bacteria and so the bacteria and so the bacteria increase greatly in number.

48
Q

What does the bacteria use up?

A

Large quantities of oxygen, reducing the oxygen availability for other organisms.

49
Q

What can genetically modified crops be used to do?

A

Reduce the use of fertilisers.

50
Q

Where can pesticides sprayed onto crops accumulate?

A

In the bodies of organisms over time.

51
Q

What is bioaccumulation?

A

The build-up of toxic substances in living organisms.

52
Q

As the build-up of pesticides is passed along food chains what happens?

A

Toxicity increases and can reach lethal levels.

53
Q

What can be used as an alternative to pesticides?

A

The use of biological control and genetically modified crops.

54
Q

What is a mutation?

A

A random change to genetic material

55
Q

What can mutation do?

A

Confer an advantage or a disadvantage to survival. They can also be neutral.

56
Q

Mutations are…

A

spontaneous and are the only source of new alleles.

57
Q

What can increase the rate of mutation?

A

Environmental factors

58
Q

What are some examples of environmental factors that can increase the rate of mutation?

A

Radiation and some chemicals.

59
Q

What can new alleles produced by mutation result in?

A

Plants and animals becoming better adapted to their environment.

60
Q

What is an adaptation?

A

an inherited characteristic that makes an organism well-suited to survival in its environment. (these adaptations can be structural or behavioural)

61
Q

What can variation within a population make it possible to do?

A

To evolve over time in response to changing environmental conditions.

62
Q

What do species produce?

A

More offspring than the environment can sustain.

63
Q

When does natural selection or survival of the fittest occur?

A

When there are selection pressures?

64
Q

What is a selection pressure?

A

Intense competition or predation where only the individuals that best fit the niche survive.

65
Q

What happens to the best-adapted individuals?

A

They survive to reproduce, passing on the favourable alleles that confer the selective advantage.

66
Q

What happens to the favourable alleles that are passed on?

A

These alleles increase in frequency within the population.

67
Q

When does speciation occur?

A

Speciation occurs after a population becomes divided by an isolation barrier, which can be geographic, ecological or behavioral.

68
Q

What is speciation?

A

Is the formation of a new species.

69
Q

Where do different mutations occur?

A

In each sub-population.

70
Q

What could a geographical isolation barrier be?

A

A river, ocean or mountain range.

71
Q

What could an ecological isolation barrier be?

A

A different toleration in pH or salinity.

72
Q

What could a behavioural isolation barrier be?

A

A preference to mate with an individual with a particular allele.

73
Q

Why does natural selection select for different mutations in each group?

A

due to selection pressures

74
Q

Each sub-population evolves until…

A

they become so genetically different that they are two different species.

75
Q

What happens to the energy absorbed by a producer during photosynthesis or consumed by an animals in a transfer from one level in a food chain to the next?

A

The majority of the energy is lost as heat, movement or undigested materials.

76
Q

How much of the energy in food is used for growth and what does this lead to?

A

Only a very small quantity of energy is used for growth and ends up within the molecules of the organism. Only this energy is available at the next level in a food chain, this is why each stage of the pyramid gets smaller.

77
Q

What does a pyramid of numbers show?

A

The total number of individual organisms at each level in the food chain of an ecosystem.

78
Q

What does a pyramid of energy show?

A

The total quantity of available energy stored in the organisms at each level in the food chain of an ecosystem per year.

79
Q

Why does a pyramid of numbers not always have a regular pyramid shape?

A

Because it does not take into account the size of the different organisms involved.

80
Q

How can the total quantity of available energy stored be estimated?

A

By burning samples of organisms and measuring the heat released.

81
Q

Do pyramids of energy always remain the same pyramid shape?

A

Yes

82
Q

How can the different body sizes of organisms that result in irregular shapes of pyramids of numbers be represented as?

A

True pyramids of energy.

Biology (7 decks)

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