natural selectiom, classification, biodiversity Flashcards

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1
Q

define population .

A
  • all organisms of particular species that live in the same place .
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2
Q

define generic diversity .

A
  • total number of diff alleles in a population
  • within population it’s increased by =
  • DNA mutations (give rise to new alleles ) +
  • migration of individuals with diff alleles from another population which reproduce (gene flow)
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3
Q

what advantage does a high genetic diversity provide ?

A
  • ability to adapt to a change in environment , allows natural selection to occur
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4
Q

explain what’s meant by genetic bottlenecks ?

A
  • when a population is greatly reduced in size —> reduced no. diff alleles in the gene pool .
  • remaining population reproduce a re-populate the area —> new population with less genetic variation
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5
Q

explain how natural selection results in development of new characteristics

A
  • process which species evolve

1) there’s variation within population = gene mutations cause new alleles to appear in population

2) organisms with alleles which give suited characteristics to environment more likely survive + pass genes to offspring
—> compared to indiv not have beneficial alleles

3) greater proportion individ in next generation inherited advantageous allele = pass on advantageous allele to their offspring

4) over time = frequency of advantageous allele increases in population (evolution)

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6
Q

what is directional selection ?

A
  • occurs when environmental conditions change
  • individuals with phenotypes suited to new conditions will survived + pass on their genes
  • over time the mean of population move towards these characteristics
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7
Q

give an example of directional selection

A
  • antibiotic resistance
  • bacteria with mutation allowing them to survive in presence of antibiotics will reproduce
  • thus, frequency of this allele increase + population shift to have greater antibiotic resistance
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8
Q

what is stabilising selection ?

A
  • occurs when environmental conditions stay the same
  • individuals closest to mean are favoured, any new characteristics selected against
  • results in low diversity
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9
Q

give an example of stabilising selection.

A
  • birth weight = that weigh around 3kg more likely survive than those at lower or higher weights
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10
Q

define a niche.

A
  • the role of a species within its environment
  • species sharing same niche will compete with each other
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11
Q

what are the three types of adsorptions? give examples

A

1) anatomical (changed to body structure) e.g = fur

2) physiological (changes to bodily processes) e.g = venom production

3) behavioural (changes to actions) e.g= hibernation

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12
Q

explain all adaptions in detail

A
  • behavioural - the way that an organism acts which increase its changes of survival
  • physiological - processes occur within body of organism which increases it chances of survival
  • anatomical = structural features of an organisms which increase changes of survival
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13
Q

define species .

A
  • a group of organisms that can interbreed to produce fertile offspring
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14
Q

what are the advantages of courtship behaviour ?

A
  • individuals can recognise sexually mature members of their own species of opposite sex , synchronise mating + form pair bond and successfully breed
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15
Q

define classification .

A
  • the process of arranging organisms into groups
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16
Q

name the 8 groups of organisms can be classified into, from largest to smallest

A
  • domain—> kingdom—> phylum—> class—> order—> family—> genus—> species
17
Q

what system is used to give species a universal name?

A
  • binomial naming system .
18
Q

what are the two components to a binomial name ?

A
  • generic name = the genus the organism belongs to . 2 closely related species will share same genus
  • specific name = the species the organism belongs to
19
Q

how are the binomial names handwritten?

A
  • the first letter of generic name should be capitalised , with rest in lowercase . the whole name should be underlined
20
Q

what is phylogenetic classification?

A
  • the process of arranging organisms into groups based on their evolutionary origins and relationships
21
Q

how can we clarify evolutionary relationships between organisms?

A
  • analyse their molecular differences .
  • advances in immunology/genome sequencing provide clear pictures of how related two organisms are
22
Q

explain hierarchical classification

A
  • groups within groups
  • no overlap between groups
23
Q

what is biodiversity ?

A
  • variety of living organisms , it can be measured in terms of species diversity (no. species in community) , ecosystem diversity (range of diff habitats ) + genetic diversity
24
Q

define community.

A
  • all the diff species that live in one area and interact with each other.
25
Q

how do you calculate index of diversity?

A
  • d = N(N - 1)
    ————
    ∑n (n - 1)
  • N = total no. organisms of all species
  • n = total no. organisms of each species
  • ∑ = sum of
26
Q

what impact does farming have on species diversity ?

A
  • decreases species richness
  • farmland is typically used for only 1 species (monoculture)
  • use of pesticides/ herbicides
27
Q

what impact does farming have on genetic diversity ?

A
  • decreases
  • farmers select for certain characteristics , which reduces no. diff alleles in population
28
Q

how can biodiversity be increased in areas of agriculture ?

A

1) use hedgerows instead of fences .

2) grow diff crops in same area, or rotate crops around after a season.

3) limit use of pesticides and herbicides

29
Q

name 4 ways we can compare genetic diversity between organisms .

A

1) frequency of observable characteristics

2) base sequence of DNA

3) base sequence of mRNA

4) amino acid sequence

30
Q

what’s meant by gene technology ?

A
  • sampling DNA or mRNA in order to read and compare base sequence of organisms
  • alternatively amino acid sequence can be studies as this will provide info on organisms mRNA and DNA sequence
31
Q

why do scientists prefer to use gene technology rather observation?

A
  • simply inferring DNA differences by observing an organisms characteristic not reliable
  • the characteristics could be coded for by more than one gene, or could be influenced by the environment
32
Q

what’s meant by interspecific and intraspecific variation ?

A
  • inter = differences between individuals of different species
  • intra = differences between individuals of the same species
33
Q

what is sampling ?

A
  • selecting a group of individuals to measure that will represent the whole target population .
34
Q

how can random sample be achieved ?

A
  • create a grid for sample area , randomly generate coordinates where quadrant or transect can be placed.
  • repeat until required sample size is reached