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Biology > topic 7 > Flashcards

topic 7 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

ecosystem

A

Group of interrelated organisms and their physical environment. Living and non living components interact

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2
Q

environment

A

Set of conditions surrounding an organism. Abiotic factors within an ecosystem.

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3
Q

abiotic

A

Non-living, physical conditions of an ecosystem (temperature, pH, light, soil conditions (EDAPHIC))

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4
Q

biotic

A

Effects of the activities of living organisms on other organisms

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5
Q

population

A

Group of organisms of the same species living in a habitat at the same time

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6
Q

community

A

All individuals of different species living in the same place at the same time

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7
Q

habitat

A

Part of an ecosystem in which particular organisms live

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8
Q

microhabitat

A

Immediate surroundings (especially for small organisms)

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9
Q

niche

A

An organisms habitat and role within an ecosystem (what it eats, predators, conditions it lives in)

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10
Q

genotype

A

the complete set of genetic material of an organism

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11
Q

phenotype

A

the observable traits or characteristics of an organism. Determined by genotype and environmental factors

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12
Q

dominant

A

only a single allele is required for the characteristic to be expressed in the phenotype

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13
Q

recessive

A

the characteristic is only expressed if there is no dominant allele present. must be homozygous recessive for the phenotype to be expressed

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14
Q

codominant

A

both alleles are expressed in the phenotype

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15
Q

allele

A

another form of a gene

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16
Q

locus

A

the position of a gene on the chromosome

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17
Q

homozygous

A

a pair of homologous chromosomes carrying the same alleles for a single gene

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18
Q

heterozygous

A

a pair of homologous chromosomes carrying two different allels for a single gene

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19
Q

multiple alleles

A

more than 2 alleles for a single gene

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20
Q

sex linkage

A

a gene whose locus is on a sex chromosme

21
Q

autosomal linkage

A

genes that are located on the same chromosome, not sex chromosome

22
Q

epistasis

A

when one gene modifies or masks the expression of a different gene

23
Q

monohybrid

A

genetic inheritance cross of a characteristic determined by one gene

24
Q

dihybrid

A

genetic inheritance cross of a chracteristic determined by two genes

25
Q

assumptions for the Hardy-Weinberg equation

A
  • no mutations occur to create new alleles.
  • there is no movement of alleles into or out of the population by migration.
  • the population is large.
  • there is no selection, so every allele has an equal chance of being passed to the next generation.
  • mating is random.
26
Q

what is the hardy weinberg equation used for

A

to estimate the frequency of alleles in a population and to see whether a change in allele frequency is occurring in a population over
time

27
Q

what does each letter represent in the hardy weinberg equation

A

p= frequency of dominant allele
q= frequency of recessive allele
p^2= frequency of homozygous dominant
2pq= frequency of heterozygous
q^2= frequency of homozygous recessive

27
Q

what does each letter represent in the hardy weinberg equation

A

p= frequency of dominant allele
q= frequency of recessive allele
p^2= frequency of homozygous dominant
2pq= frequency of heterozygous
q^2= frequency of homozygous recessive

28
Q

gene pool

A

all of alleles of all the genes within a population at one time

29
Q

population

A

all of the individuals of one species in one area at one time

30
Q

allele frequency

A

the proportion of an allele within a gene pool

31
Q

what is disruptive selection

A

-when individuals which contain the alleles coding for either extreme trait are more likely to survive and pass on their alleles
-allele frequency changes so more individuals possess the allele for the extreme trait while the middling trait becomes less frequent
-this can lead to speciation

32
Q

what is speciation

A

the creation of new species

33
Q

what is allopatric speciation

A

-populations become geographically separated e.g. mountain ranges, bodies of water, so they are now unable to reproduce
-within each population, random mutations lead to genetic variation
-both separate populations will have different beneficial mutations over time to help them survive in their environments
-eventually they become so genetically different that they are unable to interbreed to produce fertile offspring

34
Q

what is sympatric speciation

A

-populations can become reproductively isolated due to differences in their behaviour
-may be due to a random mutation within the population that impacts reproductive behaviour (e.g. being fertile at different times of the year)
-these individuals will not reproduce with eachother and there will be no gene flow between the two groups within the population
-eventually, these reproductively isolated populations will accumulate different mutations until they can’t interbreed to produce fertile offspring

35
Q

what is genetic drift

A

-change in the allele frequency within a population between generations
-continual, substantial genetic drift results in evolution
-affects smaller populations more so evolution occurs more rapidly in smaller populations

36
Q

how do abiotic factors affect population size

A

include:
-temp
-O2 and CO2 conc
-light intensity
-pH
-soil conditions
plants and animals are adapted to the abiotic conditions in their ecosystem which develop through natural selection
less harsh conditions e.g. lots of light and water mean larger range of species and larger population sizes

37
Q

how do biotic factors affect population size

A

interspecific competition- when members of different species compete for the same resource that is in limited supply
intraspecific competition- when members of the same species compete for resources and a mate

38
Q

describe mark-release-recapture

A

-initial sample of population is captured and the number is recorded
-they are then marked and released into the wild
-they are left for a period of time to allow them to randomly disperse throughout the habitat
-a second sample is captured
-the total number captured and the total number recaptured with the marking is recorded
-size of population is estimated proportionally

39
Q

equation to estimate total population

A

no. organisms initially caught x no. organisms in second sample / no. marked organisms recaptured

40
Q

ethical considerations of mark-release-recapture

A

mark should be non toxic, must not increase chances of predation or reproduction

41
Q

assumptions of mark-release-recapture

A

population size remains constant
animals redistribute evenly

42
Q

what is succession

A

the change in an ecological community over time

43
Q

describe primary succession

A

-starts with a pioneer species colonising rock or sand e.g. lichen which are adapated to live in harsh abiotic factors
-they make the environment less harsh by changing the abiotic factors and form a thin layer of soil ,humus
-mosses and small plants can now survive and further increase the depth and nutrient content of the soil
-this pattern repeats as abiotic conditions become less harsh
-each new species outcompetes the previous species
-the final stage is the climax community and is dominated by trees

44
Q

what is secondary succession

A

the succession is disrupted and plants are destroyed e.g. due to fire
succession starts again but soil is already created so it doesn’t start from the bare rock stage

45
Q

evidence that the condition is caused by a recessive allele

A

2 parents who don’t have the condition have a child who does
both parents must be carriers

46
Q

evidence that the condition is caused by a dominant allele

A

2 parents who do have the condition have a child who does not
therfore both parents must be carriers of the recessive allele but have the dominant allele

47
Q

evidence that an allele is sex linked

A

only seen in males not females

Biology (9 decks)

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