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Biology > Topic 7C: Populations in Ecosystems > Flashcards

Topic 7C: Populations in Ecosystems Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Habitat =

A

The place where an organism lives

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2
Q

Population =

A

All the organisms of one species in a habitat

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3
Q

Community =

A

population of different species in a habitat

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4
Q

Ecosystem =

A

A community + all non living conditions in the area

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5
Q

Abiotic conditions=

A

non living features of the ecosystem (temperature, availability of water)

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6
Q

Biotic conditions =

A

The living features of the ecosystem

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7
Q

Niche =

A

The role of a species w/in its habitat (what it eats, where and when it feeds)

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8
Q

Adaptations =

A

A feature that members of a species have that increases their chance of survival + reproduction

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9
Q

The niche a species occupies w/in its habitat include

A

Its biotic interactions - organisms it eats or eaten by

Abiotic interactions - oxygen an organism breathes in + the carbon dioxide it breathes out

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10
Q

Why do every species have a different niche

A

if the same there will be competition until only one species left

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11
Q

How do species avoid competition due to niches

A

every species niche is unique/ slightly different

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12
Q

Example of very similar niches

A

Common pipistrelle bat + soprano pipistrelle bat both catch insects but are differences
farmland vs woodland
hedges + urban land vs lakes + rivers
different frequencies

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13
Q

Different forms of adaptations

A
  • physiological (processes inside their body)
  • behavioural (the way an organism acts)
  • anatomical (structural features of their body)
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14
Q

Natural selection =

A

organisms with the better adaptations being more likely to survive, reproduce + pass on the alleles for that adaptation

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15
Q

Otters adaptations to abiotic conditions

A

webbed paws - they can both walk on land + swim effectively- increases chance of survival

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16
Q

Seals adaptations to abiotic conditions

A

thick layer of blubber (fat) helps keep them warm in the coldest seas - can live in places where food is plentiful

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17
Q

Hedgehogs adaptations to abiotic conditions

A

hibernate- lower their rate of metabolism over winter- increases chance of survival because they can conserve energy

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18
Q

Sea otters adaptations to biotic conditions

A

use rocks to smash open shellfish + clams- provides another source of food

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19
Q

Male frogs adaptations to biotic conditions

A

produce mating calls to attract females- increases chance of reproduction

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20
Q

Bacteria adaptations to biotic conditions

A

produce antibiotics to kill other species of bacteria in the same area- less competition

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21
Q

Carrying capacity =

A

The maximum stable population size of a species that an ecosystem can support

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22
Q

Examples of abiotic factors

A

light, water, space available, temperature, chemical composition of the surroundings

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23
Q

Advantages of a mammals surrounding being the optimum temperature

A

metabolic reactions can take place without using as much energy maintaining the body temperature- more energy used for growth + reproduction so increased population

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24
Q

Interspecific competition

A

when organism of different species compete with each other for the same resources e.g. red and grey squirrels

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25
Q

Impact of interspecific competition

A

resources available to both populations are reduced e.g. if food they’ll have less energy for growth + reproduction so population size decreases

26
Q

Intraspecific competition

A

when organisms of the same species compete with each other for the same resources

27
Q

Correlation between population and amount of resources

A
  • population increases when resources increases
  • eventually resources become limiting so population begins to decline
  • Smaller population- less competition = better for growth + reproduction- population grows again
28
Q

Predation =

A

where organism kills and eats another organism

29
Q

Population sizes of predator and prey are

A

interlinked- as population of one changes it causes the other to change

30
Q

Correlation between predator and prey population

A

-As prey increases there’s more food for predators so population also increases
-predator population increases so more prey eaten so prey population decreases
-less food for predators so population decrease
(Cycle)

31
Q

How to produce a random sample

A
  • choose an area to sample
  • samples should be random to avoid bias
  • use appropriate technique
  • repeat process as many times as possible to reduce likelihood that results are due to chance
  • number of individuals for the whole area can be estimated by taking the mean of the data collected in each sample + multiplying it by the size of the whole area
32
Q

Quadrats and transects are used to investigate

A

non mobile organisms or very slow moving organisms (like limpets)

33
Q

Quadrats =

A

a square frame usually divided into a grid of 100 smaller squares by strings attached across the frame

34
Q

How to use quadrats

A

-placed on a ground at different points - the species frequency (how often a species is found) is recorded in each quadrant

35
Q

Using quadrats to work out percentage cover

A

counting how much of the quadrat is covered by the species- counting if more than half a square is covered
-quick way to investigate populations + you don’t have to count all the individual organisms

36
Q

Transects =

A

lines to help find out how different plants are distributed across an area e.g. when organism near a hedge or water

37
Q

Belt transects =

A

quadrats placed next to each other along the transect to work out species frequency + percentage cover

38
Q

Interrupted belt transect + why its used

A

quadrats placed at intervals along the line with spaces in between to cover larger distances

39
Q

Mark- release- recapture method used to investigate

A

more motile species

40
Q

How to perform the mark- release- recapture method

A
  • capture a sample of a species using a appropriate technique + count
  • mark in a harmless way
  • release back into their habitat
  • wait a week then take a second sample from the same population
  • count how many of the second sample are marked- use the equation to estimate the total population size
41
Q

Equation for calculating population size in the mark- release- recapture method

A

no. caught in 1st sample x no. caught in 2nd sample /no. marked in 2nd sample

42
Q

Three main assumptions you have to make when doing the mark- release recapture method

A
  1. the marked sample has had enough time + opportunity to mix back into the population
  2. The marking hasn’t affected the individuals chances of survival + marking still visible - not rubbed off
  3. no changes in population size due to births, deaths + migration in this period of study
43
Q

How would you investigate the effect of soil pH on marram grass in a coastal ecosystem

A
  1. place a tape measure in a straight line from the shore heading inland= your transect
  2. take 1m^2 quadrat + divide into 100 squares
  3. starting from shore place the quadrat next to the tape measure
  4. count the squares containing marram grass + record the results in a table as percentage cover
  5. At each sample point measure the pH
  6. Repeat observations every 10 m along the transect
44
Q

Coastal ecosystem investigation:

How to measure pH

A

Can use a digital pH probe or take samples of soil back to skl in a test tube for testing using a sieve to remove debris + barium sulphate, distilled water and a pH indicator- shake thoroughly and leave to settle + check colour

45
Q

Coastal ecosystem investigation: Why does pH decreases as you move inland

A

near the shore the sand/ soil contains lots of shell fragments made of calcium carbonate= an alkali compound
further inland = rotting vegetation adds organic matter to the soil = more acidic

46
Q

Coastal ecosystem investigation: Safety issues + how to avoid them

A
  • use tide timetables so you know when low tide is= best time to work
  • wear suitable clothing + footwear for weather + terrain
47
Q

Coastal ecosystem investigation: Ethical issues

A

All fieldwork affects the environment where its carried e.g. ppl walking on soil causing erosion or killing plants
investigations should be planned to have the smallest impact possible on the area

48
Q

Succession =

A

the process by which an ecosystem changes over time

49
Q

2 types of succession=

A
  1. Primary succession

2. Secondary succession

50
Q

Primary succession=

A

happens on land that’s been newly formed or exposed e.g. where volcano has erupted to form a new rock surface or where sea levels has dropped- exposing new area
-No soil or organic material to start with- just bare rock

51
Q

Secondary succession =

A

happens on land that’s been cleared of all plants but where soil remains e.g. after forest fire or forest cut down by humans

52
Q

Primary succession starts when

A

species colonise a new land surface

seed and spores are blown in by the wind and begin to grow

53
Q

Pioneer species = + why they’re important

A

the first species to colonise the area

specially adapted to cope with the harsh conditions of the new area

54
Q

Abiotic conditions of a new land surface

A

hostile e.g. no soil to retain water

55
Q

How the pioneer species change the abiotic conditions

A

they die + microorganisms decompose the dead organic material to form a basic soil

56
Q

Impact of the decomposing pioneer species forming a basic soil

A

conditions are less hostile so new organisms w/ different adaptation can move in and grow - they die + decompose too making soil deeper and richer in minerals - for more new organisms

57
Q

Impact of the constant introduction of new species on new land surfaces

A

new species make changes to the environment that might not be suitable for the previous species

58
Q

How does secondary succession happen

A

happens in the same way as primary succession but there’s already a soil layer so starts at a later stage - with already larger plants

59
Q

Dominant species in a ecosystem =

A

the species better adapted to the improved conditions and out competes the previous species already there on the land

60
Q

As succession increases ___ also increases

A

biodiversity- new species move in alongside existing species

61
Q

Climax community =

A

final stage of succession - the ecosystem is supporting the largest and most complex community of plants and animals that it can- wont change much more- its in a steady state

62
Q

Climate climax =

A

climax community

Biology (5 decks)

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