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Biology Flashcards > Genetics, Populations, Evolution And Ecosystems > Flashcards

Genetics, Populations, Evolution And Ecosystems Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Define species.

A

A group of closely related individuals which are capable of interbreeding and producing fertile offspring.

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2
Q

Define population.

A

All the individuals of a given species living together in the same area at the same time.

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3
Q

Define a community.

A

All the individuals of all species living together in the same area at the same time

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4
Q

Define habitat.

A

The place where an organism lives within an ecosystem.

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5
Q

Define niche.

A

Where an organism lives and what it does (its role). This includes what it feeds on and how it interacts with other organisms and the environment.

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6
Q

Why do only one species occupy one niche in a stable ecosystem?

A

It reduces competition between species. (interspecific competition)

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7
Q

Define abiotic factors and give examples.

A

Non-living factors which affect the distribution of an organism. Examples:
temperature, light intensity, wind speed, soil/water pH, water level in soil, slope of land.

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8
Q

Define biotic factors and give examples.

A

Living factors which affect the distribution of an organism. Examples: competition, predation, disease.

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9
Q

Define ecosystem.

A

All the living (biotic) and non-living (abiotic) components of a particular area.

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10
Q

Define carrying capacity.

A

The certain size of population of species that an ecosystem can support.

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11
Q

What is the size of a population determined by?

A
  • Effect of abiotic factors
  • Interactions between organisms (biotic factors)
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12
Q

What effect does extreme temperatures have on organisms?

A

They affect enzymes and therefore the overall metabolic system
- Too cold = enzymes do not have enough kinetic energy to catalyse reactions. An organisms activity will drop and may not be sufficient for survival.
- Too hot = enzymes start to denature. An organisms activity will drop and may not be sufficient for survival. Organisms may also experience problems with excess water loss and dehydration.

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13
Q

What are endotherms?

A

Animals (birds + mammals) that can use physiological mechanisms to maintain their body temperature (e.g. sweating, shivering)

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14
Q

How can temperature be measured?

A

-thermometer
- data logger with temperature probe

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15
Q

Why is light important for organisms?

A

It is needed in photosynthesis. More light = more photosynthesis = more energy = more seeds = plants population grows = more food for plant-eating animals = more food for meat-eating animals.

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16
Q

Why is water important for organisms?

A
  • Acts as a solvent in cells
  • Is involved in many reaction (photosynthesis, hydrolysis)
  • Acts as a hydrostatic skeleton in many species
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17
Q

How do organisms lose water to the environment?

A

Evaporation, which can be used in thermoregulation (sweating) or the movement of mineral salts and water through the xylem.

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18
Q

The lower the humidity, ____ water loss via evaporation occurs due to a _____ ________ gradient

A

more, water potential

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19
Q

How is humidity measured?

A

Whirling hygrometer or data logger with humidity probe.

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20
Q

Why is pH important for organisms?

A
  • It can affect enzymes and surface proteins. Extreme pH = more enzymes denatured = metabolic rate decreases = death of organism = population decreases. It also would decrease the range of species present in an ecosystem and the availability of mineral salts in soil.
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21
Q

In extreme abiotic factors, ____ species can tolerate them and the ______ population sizes will be.

A

less, smaller

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22
Q

Define intra-specific competition.

A

Competition between members of the same species.

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23
Q

Define inter-specific competition.

A

Competition between members of different species.

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24
Q

What happens if there are two species occupying the same niche?

A

One species tends to outcompete the other and eventually the niche will be occupied by one species (known as the competitive niche exclusion principle)

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25
Q

Define predation.

A

When one animal species (the predator) feeds on another animal species (the prey).

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26
Q

What are examples of adaptations predators have to improve their ability to capture prey?

A

moving at high speeds, venom, secretions

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27
Q

What are examples of adaptations prey have to improve their ability to defend against predators ?

A

camouflage, protective spines, large peripheral vision

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28
Q

How are predator prey relationships connected?

A

Prey population increase = more food for predators so intraspecific competition decrease = predator population increases = increased predation of prey = prey population decreases = increased predator intraspecific competition predator population decreases = prey population increases (cycle repeats)

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29
Q

What are three things you have to be mindful of when estimating populations/data?

A
  • Samples/data must be collected randomly to prevent bias.
  • Sample size must be large to ensure data is reliable and suitable for statistical analysis. Taking a running mean and having it show little change will show enough samples have been taken
  • Method of collection must be appropriate to the species e.g. quadrats for slow or immobile organisms.
30
Q

What is a quadrat?

A

It is a frame of known area which is placed on the ground and an estimate of the population sizes within the quadrat are made. They can be made of metal, wood or string/rope and can be a fixed shape or flexible to fit around large objects.

31
Q

What are quadrats used for?

A

Used to measure the abundance/population of organisms.

32
Q

What are the three methods to using a quadrat?

A
  1. Actually counting all individuals present (population density) - however this can be time consuming and some species difficult to count.
  2. Percentage cover - the area covered is recorded as a percentage of the total area. Stratification may occur so percentage cover may be larger than 100%.
  3. Frequency- The proportion of quadrats that contain a particular species
33
Q

How does a point frame quadrat work and where is it used?

A

It is placed randomly and then the pins are lowered, any species touching the pins are recorded and the species frequency is recorded as % of pins touched. It is used in areas of dense vegetation.

34
Q

What sampling technique would be used here:
Compare the species abundance in two different areas or compare the species abundance at different times. For immobile species.

A

Random quadrating

35
Q

What sampling technique would be used here:
Find out how the species abundance varies across an area e.g. does the plant distribution change when you cross a sand dune. For immobile species.

A

Systematic sampling

36
Q

What sampling technique would be used here:
For fast moving species.

A

Mark Release Recapture

37
Q

How do you preform random quadrating?

A
  1. Arrange two measuring tapes at right angles to make a grid
  2. Randomly generate two coordinates using a random number generator on a calculator. Place quadrat at intersection
  3. Abundance can be estimated using one of the three methods
  4. Repeat a large number of times until running mean has little difference
  5. Calculate average number of organisms per quadrat or per metre squared
  6. Times by the size of the area being investigated to give estimate of population
38
Q

How do you preform systematic sampling?

A
  1. Area of transects should be random and there should be many of them placed
  2. Decide an appropriate interval to sample
  3. Abundance can be estimated using one of the three methods
  4. Repeat a large number of times until running mean has little difference
39
Q

What is a transect?

A

It is a line across the area and sampling is preformed at set predetermined intervals along the line e.g. every 5 metres. This method can specifically be used to measure succession over an area.

40
Q

What would be an appropriate stats test for systematic sampling?

A

A spearman’s rank

41
Q

What would be an appropriate stats test for random quadrating?

A

A student T test

42
Q

How do you preform mark release recapture?

A
  1. Capture the first sample (using netting or trap technique)
  2. Mark the animal in some way ( paint dots, tagged etc.). This shouldn’t make the organism susceptible to predation.
  3. Release the animals and wait an appropriate amount of time for them to redistribute into the population.
  4. Preform a second capture and the total number caught and amount marked is recorded.
  5. Use the equation to estimate the population.
43
Q

What is the equation used to calculate the population size after using the mark release recapture method?

A

N1 (number caught 1st) x N2 (number caught 2nd) / Nm (number marked in 2nd group)

44
Q

What are the considerations/assumptions when using the mark release recapture method?

A
  • That the population size does not change between the capture times. (should be very few births, deaths, emigration or immigration)
  • The marks should not make the animal for susceptible to predators and they shouldn’t harm the animal.
  • The marking should not rub off or be lost.
  • Sufficient time should be left between second capture.
45
Q

What are the ethics of sampling?

A
  • Species should be studied in situ and should not be removed from the sampling site.
  • If removal or disturbance is necessary, the individuals should be returned to the same spot if possible (even if dead).
  • As few individuals as possible should be removed
  • There should be minimal damage to organisms or the habitat
  • Sites should not be over used and be given time to recover.
46
Q

Describe how you would collect necessary data to estimate the size of a population by the mark-release-recapture technique. (3)

A

mp1: capture, count and release
mp2: carefully mark to avoid detection
mp3: recapture, count marked and unmarked

47
Q

Describe how you would use quadrats to determine whether a particular plant species has a clustered or random distribution. (3)

A

mp1: use of random numbers to place quadrats
mp2: number of individuals counted in large number of quadrats
mp3: little variation = random, large variation = clustered

48
Q

Describe how you would use a quadrat to estimate the number of dandelion plants in the field measuring 100m by 150m

A

mp1: Principle of randomly placed quadrats and method of producing random quadrats; (Reject ‘throwing’)
mp2: Valid method of obtaining no. dandelions in given area (mean per
quadrat / total no. in many quadrats);
mp3: Multiply to give estimate for total field area;

49
Q

Explain how the students could use the mark-release-recapture technique to estimate the number of insects. (4)

A

mp1: collect a sample (of insects in each area) and mark unobtrusively / in a way not harmful to insects;
mp2: release and allow time to re-integrate with rest of population / eq.;
mp3. collect second sample and count number marked;
mp4: number in population estimated by:
N1 x N2 / Nm
Total marked/Nm = population/N2

50
Q

Define succession.

A

Describes the series of changes that occur in a community over time. It begins on bare soil/rock/water/sand and ends in a climax community.

51
Q

What are conditions like at the start of succession?

A

The environment is hostile due to its harsh abiotic factors.

52
Q

What are pioneer species?

A

The organisms that first colonise and area e.g. marram grass on sand dunes. They are the few organisms that have adaptation that enable them to survive in harsh abiotic factors.

53
Q

Define sere.

A

A complete succession from pioneer community to climax community. A seral stage is a particular stage in this succession with its own distinctive community of organisms.

54
Q

Define climax community.

A

The final stage in ecological succession. It is stable and rarely changes. The type of community formed depends on the climate.

55
Q

Define hostility.

A

How extreme abiotic factors are in the environment. In hostile environments, abiotic factors are harsh. This means diversity is low.

56
Q

Define abiotic environment.

A

non living parts of the environment e.g. temperature, soil mineral ion concentration, salt concentration, amount of humus, water retention

57
Q

Define diversity

A

the relationship between the number of individual organisms of a species and the number of species in a community.

58
Q

Features of high diversity.

A

Highly diverse group means a wider range of species and is associated with a stable ecosystem and complex food web. If one population drops, other species will be able to increase in numbers and fill the niche.

59
Q

Features of low diversity.

A

Less diverse group means a greater number of individuals on a few species and is associated with an unstable ecosystem and less complex food web. If one population drops, then the whole ecosystem may be disrupted

60
Q

What are the stages of primary succession?

A
  • Primary succession begins with no soil, often on bare rock, which goes through erosion to create soil
  • Specialised pioneer species, that are able to survive the harsh conditions, colonise the area
  • As pioneer species die, they make the soil more fertile. This makes abiotic factors less harsh and better adapted, less specialised species colonise the area. They out compete the previous species.
  • This continues until a climax community forms.
61
Q

As succession occurs:
- Harsh abiotic factors are ________
- Become ____ stable by the ______ of complexity food webs and amount of habitats
- _____ number of species so biodiversity is _____
- Allows for species that are ____________

A
  • reduced
  • more, increase
  • Large, higher
  • larger in size
62
Q

What is secondary succession?

A

This is when succession occurs after a forest fire or clearance of agricultural land. Spores, seeds and vegetative organs may remain viable (living) in the soil and there will be an influx of animals and plants through migration and seed dispersal from the surrounding area. It begins with intermediate seres instead of pioneer species.

63
Q

Define conservation.

A

The maintenance of ecosystems and biodiversity.

64
Q

What are the reasons we want to do conservation?

A
  • Personal = To maintain resources to support life
  • Ethical = respect for other living organisms
  • Economic = increase the productivity of land
  • Cultural and aesthetic = enrichment of life
65
Q

Define in situ conservation.

A

Conservation of species in its natural environment.

66
Q

Define ex situ conservation.

A

Preservation of compounds of biological biodiversity outside their natural habitat.

67
Q

Define plagioclimax.

A

A community which is maintained by humans to prevent a climax community.

68
Q

What are some types of human intervention that effects ecosystems?

A
  • Ploughing
  • Weeding
  • Using herbicides
  • Burning
  • Crop planting
  • Grazing animals
69
Q

Explain how succession results in the formation of a forest. (4)

A

mp1: pioneers / suitable example colonise land;
mp2: example of change in environment;
mp3: enables change in species;
mp4: conditions change further / example to favour trees;

70
Q
A

Biology Flashcards (10 decks)

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