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7)populations and ecosystems > part 1 content > Flashcards

part 1 content Flashcards

1
Q

ecosystem definition

A

the community and its interaction with non-living components of the environment

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2
Q

habitat

A

is the place where an organism normally lives and is characterised by physical conditions and the other types of organisms present

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3
Q

niche

A

the role an organism plays in an ecosystem. the way that an organism fits into an ecosystem, the resources it uses and the way it effects other organisms

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4
Q

population

A

a group of individuals of the same species, living in the same geographical range at a particular time

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5
Q

community

A

all of the populations of different species, living in the same geographical range at a particular time

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6
Q

abiotic factors

A

non living components of an ecosystem that can affect survival eg water availability, temp, pH

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7
Q

biotic factors

A

living components of an ecosystem that can effect survival eg predation, competitors, prey

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8
Q

interspecific competition

A

competition between different species

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9
Q

intraspecific competition

A

competition between members of the same species

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10
Q

carrying capacity

A

the maximum population size that can be sustainably supported by an ecosystem/ habitat

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11
Q

competitive exclusion

A

no two species occupy the same niche, the more similar the niche, the more intense interspecific

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12
Q

predation

A

predators killing and eating another organism (its prey)

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13
Q

what is population size limited by?

A

abiotic factors

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14
Q

what effects population size?

A

births, immigration and death

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15
Q

examples of abiotic factors

A

temperature, water, light, pH

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16
Q

why does competition occur between organisms?

A

due to limited resources

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17
Q

what happens in infraspecific competition?

A

competition can result in natural selection as those with more advantageous characteristics survive and reproduce

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18
Q

what are the two types of competition?

A

interspecific and infraspecific

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19
Q

what individuals are most likely to survive intraspecific competition?

A

the ones best adapted to the conditions

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20
Q

what happens in interspecific competition?

A

the more similar the niches, the more intense the completition

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21
Q

what will eventually happen to one of the species?

A

competitive exclusion from the habitat/ ecosystem

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22
Q

what happens in predator-prey relationships?

A

fluctuations in the abundance of the prey (peaks and troughs) the predator mirrors these fluctuations after a time lag

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23
Q

when studying a habitat, what three questions will ecologists ask?

A

what lives there? where do they live within the area? how many there are?

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24
Q

random sampling

A

taking samples at randomly selected locations

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25
Q

systematic sampling

A

taking samples at regular intervals eg every 5m

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26
Q

abundance

A

how many organisms are present (population size)

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27
Q

frequency

A

how often an organism occurs in the habitat as a decimal or percentage

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28
Q

percentage cover

A

the proportion of a quadratic which has an organism present measured as 5%

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29
Q

mark-release recapture

A

a method used to estimate the population size of motile organisms

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30
Q

what does species density mean?

A

the number of individuals of a species per unit area

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31
Q

what equipment is needed to measure species density?

A

quadrant, random number generator to generate co-ordinates, tape measure to create grid

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32
Q

the method used for species density

A

-lay a tape measure along the length and width of the habitat
-place a quadratic randomly by using a random number generator to generate random numbers to use as co-ordinates
-count the number of individuals
-large sample size (20+ quadrants)
-find the mean
-multiply the mean by the product of unit area

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33
Q

what does linear change in distribution mean?

A

does the frequency/ density/ number of organisms change along a line

34
Q

what is a transect

A

tape measures put across the habitat. you can then use quadrants systematically not randomly along the transect. it allows you to look at distribution along a line

35
Q

what equipment is needed for linear change in distribution?

A

transect

36
Q

Line transects

A

At regular intervals e.g every 1m, note down the organism that touch the tape measure as 1( present) 0 (not present)

37
Q

Belt transects

A

Lay 2 tape measures down with the width of one quadrant between them. At regular intervals place a quadrat down and count the number of individuals/ percentage cover

38
Q

Biodiversity of an area is

A

The number of different species living in an area and the number of individuals of each species

39
Q

The equipment needed to test biodiversity of an area is

A

Quadrat, ID card, random number generator, tape measure

40
Q

Method used to test the biodiversity of an area

A

Lay a tape measure along the length and width of the habitat. Place quadrat by using a random number generator to generate random numbers to use as co-ordinates. Identify species present using ID card. Record the number of species present in the quadrat and the number of individuals of each species, large sample size (20+ quadrants) find the mean of each species. The population size of each species by multiplying the mean by the product of (area of the habitat/ area of the quadrat) for each species. Calculate the biodiversity using the index of biodiversity equation

41
Q

Population size of a non-motile/slow moving organism method

A

Lay a tape measure along the length and width of the habitat, place quadrant randomly by using random number generator to generate random number to use as co-ordinates, count the number of individuals, large sample size (20+ quadrants) find the mean, multiply the mean by the product of ( area of habitat/area of quadrat)

42
Q

Population size of a motile organism method

A

-capture, record the number of individuals caught
-mark you it’s a non-toxic tag that will not affect its survival
-release and allow sufficient time for re-distribution in the population
-re-capture and count the number of individuals previously marked

43
Q

To find the total number in a population of motile organism you age to

A

Number in 1st sample x number of 2nd divided by number in second sample previously marked

44
Q

Assumptions made about finding the population size of a motile organism

A

The proportion of marked to unmarked individuals in the second sample is the same as the proportion in the population as a whole. The marked individuals distribute themselves evenly and have time to do so. Few if any deaths of birth in the population do not too much time allowed

45
Q

What is frequency

A

The number of times a docked occurs in an area as a proportion of the area

46
Q

Method of calculating frequency

A

-lay a tape measure along length and width of the habitat
-place quadrant randomly by using random number generator to generate random numbers to use as co-ordinates
-if the species is present (regardless of how much) record a 1. If the species is not present record a 0
-large sample size (20+ quadrants)
-find the percentage of quadrants that the species occurred in by using number of quadrants where species is present/total number of quadrants

47
Q

What is succession

A

The process of ecosystems changing overtime, increasing in biodiversity

48
Q

Why is primary succession?

A

On previously uncolonised land eg bare rock after a volcanic eruption

49
Q

Why is primary succession?

A

On previously uncolonised land eg bare rock after a volcanic eruption

50
Q

What is secondary succession?

A

On land previously colonised destroyed but soil and mineral ions are still present

51
Q

What is the name of the first species to colonise?

A

Pioneer species

52
Q

What is the name of the first species to colonise?

A

Pioneer species

53
Q

How are these species adapted?

A

Tolerate extreme/hostile conditions, reproducing asexually, producing large numbers of wind dispersed seeds/spores/pollen/gametes, rapid germination (no period of dominancy) nitrogen fixing (add nitrates into the soil) ability to photosynthesise as light will be present but food will not

54
Q

What is the final stage of succession? Give details of how biodiversity and biomass changes

A

Climax community

55
Q

Common features succession

A

The organisms at one stage change the abiotic conditions making it less hostile/more suitable for other species with different adaptations. The next species to arrive change the abiotic conditions making it less suitable for the species wich causes a reduction in their abundance

56
Q

Explain how succession occurs

A

-colonisation by pioneer species
-change abiotic factors making the environment less hostile by forming humus
-this enables other species to colonise which outcompete pioneer species
-thus causes an increase in biodiversity, as more plants species allow more animal species to survive due to increased habitats and niches
-climax community in the most stable ecosystem

57
Q

Conservation definition

A

Protection and management of the earths natural resources to ensure their maximum potential is utilised while minimising disruption to living organisms

58
Q

Why is it important to carry out conservation?

A

Ethical-respect for all living organisms
Economic-living organisms contain a huge pool of genes with the capacity to make millions of substances some may prove to be useful in the future.long term productivity is greater if ecosystems are maintained in their natural balanced state
Cultural and aesthetic-habitats and organisms enrich our lines,provide a source of inspiration for artists etc understanding other organisms may help us understand ‘us ‘ better
Personal-to maintain the plant and life support systems in a sustainable way-to meet the needs of people today without reducing the ability of people in the future to meet their own needs

59
Q

Why is conservation important in managing succession?

A

Human intervention and management of the ecosystem to prevent the next stage occurring can conserve these habitats. As succession progresses many early species are outcompeted by later species or they are no longer present because their habitats have disappeared

60
Q

How is the Peak District managed?

A

The climax community does not occur as heather is burnt and sheep graze the land.young tree sampling cannot survive and natural succession to deciduous woodland is prevented

61
Q

Conservation needs to be sustainable.what does the term sustainable mean

A

Conservation needs to be carried out in a sustainable way.sustain able means there are enough resources to meet of people today without reducing the ability of people being able to meet their needs in the future. There can be conflict between what humans need and the conservation of a particular ecosystem and a balance that must be struck

62
Q

What are other ways of conserving species?

A

Zoos
Limits dog souvenirs
Conservation of areas
Legislation

63
Q

What are other ways of conserving species?

A

Zoos
Limits dog souvenirs
Conservation of areas
Legislation

64
Q

What is speciation?

A

A new species formed from an existing species which it can no longer interbreed with to produce fertile offspring. This is due to an accumulation of genetic differences

65
Q

What is reproductive isolation?

A

When individuals are prevented from interbreeding. This can be due to geographical isolation, behavioural or physiological reasons

66
Q

What is alleluia frequency?

A

The allele frequency is the number of times an allele appears in the population as a proportion of the total number of alleles

67
Q

What are the two types of speciation?

A

Allopathic (geographical)
Sympathetic (reproductive)

68
Q

What are the two types of speciation?

A

Allopathic (geographical)
Sympathetic (reproductive)

69
Q

Give an example of allopathic speciation?

A

A new mountain range separates two groups from the same population. A storm whisks some members of the population to another island. A river is diverted and separates two populations

70
Q

Give an example of allopathic speciation?

A

A new mountain range separates two groups from the same population. A storm whisks some members of the population to another island. A river is diverted and separates two populations

71
Q

Example of sympatric speciation

A

Mutation causes a delay to the time of year pollen is released. Mutation causes breeding season to change. A change in courtship behaviour so species recognition does not occur. Feeding times become different

72
Q

Species

A

A group of organisms that breed together to produce fertile offspring

73
Q

Specification

A

The evolution of a new species from existing ones, causes by a change in the frequency of alleles in a population

74
Q

Allele frequency

A

The number of times an allele occurs within the gene pool

75
Q

Reproductive isolation

A

Breeding between two populations, stops happening in speciation

76
Q

Evolution

A

A change in the allele frequencies in a population overtime

77
Q

Evolution

A

A change in the allele frequencies in a population overtime

78
Q

Explain allopathic speciation

A

Reproductive isolation occurs ( due to geographical isolation) there is no gene glow between the two populations so their gene pools are isolated
Different random mutations accumulate in each population causing genetic differences
Selection pressures in the two areas are different
Natural selection affects the two populations differently so the allele frequency in each population will change when they become too genetically different they can no longer interbreed to produce fertile offspring so a new species is formed

79
Q

Explain sympatric speciation

A

Reproductive isolation occurs (not due to geographical isolation) there is no gene flow between the two populations so their gene pools are isolated
Different random mutations accumulate in each population causing genetic differences
Selection pressures in the two areas are different
Natural selection affects the two populations differently so the allele frequency in each population

80
Q

Explain sympatric speciation

A

Reproductive isolation occurs (not due to geographical isolation) there is no gene flow between the two populations so their gene pools are isolated
Different random mutations accumulate in each population causing genetic differences
Selection pressures in the two areas are different
Natural selection affects the two populations differently so the allele frequency in each population

7)populations and ecosystems (9 decks)

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