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Biology A level > Genetic diversity, biodiversity > Flashcards

Genetic diversity, biodiversity Flashcards

3.4.4, 3.4.5, 3.4.6, 3.4.7 (87 cards)

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1
Q

what is an allele?

A

a variant form of a gene

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2
Q

what do alleles code for?

A

different versions of characteristics eg blonde hair or brown hair

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3
Q

what is genetic diversity?

A

the number of different alleles of genes in a species or population

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4
Q

how does genetic diversity lead to variation?

A

different combinations of alleles means different proteins are produced resulting in different characteristics

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5
Q

how does genetic diversity impact natural selection?

A

genetic diversity influences natural selection as organisms with advantageous traits are more likely to survive, reproduce and pass on thru alleys, influencing the gene pool

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6
Q

describe the process of natural selection and how is this an advantage to the species

A
  1. there is variation in characteristics within a species
  2. more genetic variation emerges within a population due to random mutations
  3. individuals with alleles that code for traits that are advantageous for survival are more likely to reproduce
  4. these advantageous alleles are passed down to offspring
  5. over many generations the beneficial alleles become more common in the population

this mechanims leads to populations becoming more adapted to their environment over generations

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7
Q

what is a genetic bottleneck?

A

an event that causes a big reduction in a population reducing the number of different alleles in the gene pool and therefore racing genetic diversity

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8
Q

what is the founder effect?

A

the founder effect describes what happens when just a few organisms for a population start a new colony and there are only a small number of different alleles in the gene pool

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9
Q

what can cause the founder effect?

A

migration leading to geographical separation or if a new colony is separated from the original population for another reason

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10
Q

what is natural selection?

A

the process in which the mutation produces alleles that codes for a characteristic that increases the chances of an organism surviving therefore causing the frequency of the variation in the population to increase

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11
Q

what is evolution?

A

the gradual change in a species over time

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12
Q

what are the 2 types of selection?

A

directional selection
stabilising selection

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13
Q

what is directional selection?

A

where the individuals with alleles for characteristics of an extreme type are more likely to survive and reproduce - this could be in response to an environmental change

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14
Q

what is stabilising selection?

A

a type of natural selection that favours individuals with the average phenotype and selects against extreme phenotypes reducing variation in a population

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15
Q

what is a phenotype?

A

the observable characteristics of an organism resulting from its genotype and the environment

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16
Q

what is a genotype?

A

the specific combination of alleles an organism possesses for a particular gene or trait

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17
Q

what effect does directional selection have on the normal distribution curve?

A

shifts the curve in the direction of the favoured extreme

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18
Q

what effect does stabilising selection have on the normal distribution curve?

A

it narrows the curve

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19
Q

what is an example of directional selection?

A

antibiotic resistance in bacteria where the resistant bacteria survive and reproduce

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20
Q

what is an example of stabilising selection?

A

human birth weight where infants of average weight have higher survival rates

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21
Q

what are adaptations?

A

inherited characteristics that enhance an. organisms ability to survive and reproduce in its specific environment

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22
Q

what are the 3 types of adaptations

A

behavioural adaptations
physiological adaptations
anatomical (structural) adaptations

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23
Q

what is behavioural adaptations?

A

the way the organism acts/responds whether inherited or learned that increase its chance of survival

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24
Q

what is physiological adaptations?

A

the internal processes in an organism that increase its chance of survival

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25
what are anatomical (structural) adaptations?
the internal and external physical structural features of an organisms body that increase its chance of survival
26
give examples of anatomical adaptations
body coverings - fur feathers scales camouflage - organisms with colouration that blends into their environment so are less likely to be detected mimicry - some species imitate the appearance of more dangerous ones for protection teeth - shape of animals teeth adapted for its diet
27
give examples of behavioural adaptations
defensive responses - playing dead or freezing to avoid detection courtship displays - dancing to attract mates seasonal actions - migration helps birds to access resources year round or hibernation helps bears to conserve energy when food is scarce
28
give examples of physiological adaptations
venom antibiotics - produced by bacteria to outcompete rival species water storage - Desert frogs can survive for over a year without a water source by storing water in their bodies
29
what is phylogeny?
the study of evolutionary history of a group of organisms
30
what are the 8 taxonomic ranks used to classify organisms in order?
1. Domain 2. Kingdom 3. Phylum 4. Class 5. Order 6. Family 7. Genus 8. Species (King Philip Coughed On Fred and he Got Sick)
31
what are the 3 domains that organisms can be classified into?
1. Bacteria 2. Archaea 3. Eukarya
32
what 4 kingdoms does eukarya include?
plantae (plants) Animalia (animals) protoctista (unicellular eukaryotes) fungi eg yeast
33
what is binomial nomenclature?
the binomial naming system that gives each species a 2 part latin name
34
how is each species universally identified?
a binomial consisting of: 1. the genus - uppercase first letter 2. the species - all lowercase
35
what are courtship behaviours?
courtship behaviours are carried out by organisms to attract a mate of the same species
36
what are the purposes of courtship behaviours?
- enables animals to recognise members of their own species leading to successful mating and the production of fertile offspring - identifies a mate that is capable of breeding ie sexually mature and fertile - forms a pair bond leading to successful mating and the raising of offspring - synchronises mating so that it takes place when there is the maximum probability of the sperm and egg meeting - animal becomes able to breed as courtship behaviour brings the member of the opposite sex into a physiological state allowing breeding to occur
37
what is phylogenetic classification based on?
evolutionary relationships between organisms and their ancestors
38
describe the features of phylogenetic classification
- based on the evolutionary relationships between organisms and their ancestors - classifies species into groups using shared features derived from their ancestors - arranges the groups into a hierarchy in which the groups are contained within larger composite groups with no overlap
39
describe the structure of a phylogenetic tree
- the position of branching points reflects how recently species shared a common ancestor - the length between branches represents how closely related species are in evolutionary terms - species that are close together on the tree are more closely related evolutionarily
40
what is divergence?
the separation of 2 or more groups from a common ancestor
41
what is taxonomy?
the science of classification
42
what does taxonomy involve?
naming organisms and organising them into groups
43
what are the groups used to classify organisms called?
taxa singular group - taxon
44
how are the groups used to classify organisms arranged?
in a hierarchy with largest groups at the top and smallest group at the bottom
45
in what ways has modern technology helped scientists in being able to classify organisms more accurately?
- comparison of DNA base sequences between organisms - genome sequencing - comparison of the base sequence of mRNA - comparison of amino acid sequences in proteins
46
what does the comparison of an organisms DNA base sequence or amino acid sequence or immunological responses show?
DNA base sequence - high similarity in base sequence shows how closely related a species is amino acid sequence - proteins are coded for by DNA so high similarity in amino acid sequence shows how closely related a species is immunological - similar proteins will bind to the same antibodies
47
what limitations arise when assessing genetic variation by examining observable phenotypic traits?
environmental factors can alter traits leading to variations that are not genetically based
48
define biodiversity
the variety of organisms in an area
49
define a habitat
the place where an organism lives within an ecosystem
50
define community
the population of different species within a habitat
51
define ecosystem
living organisms as well as the non-living components of the environment in one area
52
what are the 3 levels of biodiversity?
Ecosystem diversity - number and different range of habitats Genetic diversity - the variety of genes / variation of alleles within a population of a species Species diversity - number of different species and number of individuals of individuals of each species within a community
53
what is interspecific variation?
variation between different species due to different genes causing differences in physical traits, adaptations, habitats etc. and due to environmental factors like climate, diet, lifestyle, etc.
54
what causes variation?
a combination of genetic and environmental influences
55
what is intraspecific variation?
variation between individuals within a species due to different alleles (gene variants) and environmental factors
56
give 2 measures of biodiversity
species richness species eveness
57
what is species richness?
the total number different species in a habitat
58
how do you measure the quantity of species richness?
taking ransom samples and counting the species present
59
what does a higher species richness indicate?
greater diversity
60
what is species eveness?
a comparison of the numbers of individuals of each species in a community
61
how do you measure species eveness?
it is measured by taking samples and counting individuals of each species
62
what a high number of species eveness indicate?
greater overall biodiversity
63
what is the equation for the index of diversity?
d = N(N-1) / En(n-1)
64
what is the index of diversity?
an equation considering species richness and eveness to quantify (measure the quantity of) biodiversity
65
What does N, n and E represent in the index of diversity calculation
N - total individuals of all species n - number of individuals of each species E - the sum of d = N(N-1) / En(n-1)
66
what does a higher value of d (the index of diversity) indicate?
greater diversity
67
how has the growing human population impacted biodiversity?
- deforestation for development destroys habitats and reduces ecosystem diversity - over use of resources causes certain species to decline or go extinct reducing genetic and species diversity - the uncontrolled expansion of cities and towns isolates wildlife populations limiting breeding and decreasing genetic diversity - pollution kills species directly and harms habitats long term
68
what affect does agriculture (farming methods) have on biodiversity?
they decrease biodiversity as species lose food/shelter/breeding sites
69
what is/are monoculture/s?
growing single crops over large areas typically without crop rotation
70
what effect does monocultures have on biodiversity?
monocultures directly decrease the diversity of plants and of species that depend on them for food and/or habitat monocultures also deplete the nutrients from the soil
71
what effect does converting woodland and hedgerows into fields have on biodiversity?
this decreases number of trees and other species, and destroys habitats relied on by many species
72
why do farmers fill ponds and drain marshes?
to create more farmland
73
what affect does filling ponds and draining marshes have on biodiversity?
it directly destroys habitats and reduces species diversity
74
how does removing weeds with herbicides affect biodiversity?
directly reduces plant diversity therefore (indirectly) affecting animals that rely on those plants for food
75
how does using pesticides to kill crop pests reduce biodiversity?
directly harms species (pests) and therefore (indirectly) harming the species that rely on those species (pests)
76
how does using inorganic fertilisers reduce biodiversity?
the inorganic fertilisers may runoff into water courses causing issues for aquatic species
77
give 4 ways to balance the development of agriculture and biodiversity
maintaining hedgerows reducing pesticide and herbicide use using organic fertilisers using crop rotation
78
what are some of the effects of climate change on biodiversity?
- different regions experience changes in temperature and rainfall and most species are adapted to specific climates - change conditions will make certain areas more or less habitable in general - suitable habitats for some species will expand or contract - changing climate conditions may influence species distribution and migration - if conditions in general become warmer, tropical disease will be more likely to be spread - rising sea levels may lead to more frequent flooding of terrestrial habitats in low lying land
79
what is random sampling?
a sampling method used to avoid bias and ensure the samples are representative of the whole population
80
what are the steps for random sampling?
- randomly generating coordinates across an area to prevent bias - collecting samples from these random coordinates to represent the population - repeating this several times as a large sample size minimises the effects of chance analysing the data collected to identify any relationships
81
what is the mode?
the single value of a sample that occurs most often
82
what does the standard deviation measure?
the spread of values around the mean within a sample
83
what does a small standard deviation indicate?
the values are fairly constant and clustered around the mean
84
what does a large standard deviation indicate?
the values are fairly inconsistent and widely spread around the mean
85
how is the standard deviation shown visually on a graph?
error bars
86
how are error bars plotted?
one standard deviation above the mean and one below (standard deviation = half the length of the full bar)
87
what do the size of the error bars indicate?
longer error bars indicate more variation around the mean within that sample

Biology A level (14 decks)

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