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ocr a level biology > chapter 10 - classification and evolution > Flashcards

chapter 10 - classification and evolution Flashcards

(52 cards)

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1
Q

interspecific variation

A

variation between species

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2
Q

intraspecific variation

A

variation within species

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3
Q

causes of genetic variation

A

random mutations recombination of allelles

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4
Q

causes of environmental variation

A

eg climate, diet and lifestyle

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5
Q

features of discontinuous variation

A

phenotypes fall into distinct categories displayed on a bar chart controlled by one/two genes

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6
Q

features of continuous variation

A

a continuous range of values between two extremes displayed on a line graph genes provide an additive effect influenced by the envionement as well as genetics

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7
Q

species

A

a group of organisms that are very similar in appearance, anatomy, physiological biochemistry and genetics that can breed with each other to produce fertile offspring

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8
Q

convergent evolution

A

the evolution of similar features in distantly related species

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9
Q

linnaean classification system

A

domain kingdom phylum class order family genus species

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10
Q

features of prokaryotes (prokaryotae)

A
  • no nucleus - loop of DNA not arranged in chromosomes - naked DNA - no membrane-bound organelles
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11
Q

features of protoctists (protoctista)

A
  • single-celled - wide variety of forms - display various plant-like or animal-like features - autotrophic and heterotrophic nutrition - eukaryotic
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12
Q

features of fungi

A
  • cell walls made of chitin - cytoplasm is multinucleate - exist as single cells or have mycelium that consists of hyphae - eukaryotic
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13
Q

features of plants (plantae)

A
  • multicellular - cell walls made of cellulose - contain chlorophyll - autotrophic nutrition (photosynthesis) - eukaryotic
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14
Q

features of animals (animalia)

A
  • multicellular - able to move around - nervous system - heterotrophic nutrition - eukaryotic
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15
Q

modern classification

A

heavily relies on molecular evidence species that have similar sequences of DNA are more closely related

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16
Q

classification

A

a way to group organisms using the similarities and differences between them

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17
Q

what are the three domains?

A

bacteria, archaea and eukaryotes

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18
Q

how are archaea different to bacteria?

A
  • different cell membrane structure - different enzymes for building RNA - bacteria don’t have proteins bound to genetic material - different DNA/RNA replication mechanisms
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19
Q

how are archaea similar to eukaryotes?

A
  • similar enzymes for building RNA - similar mechanism for DNA replication - both produce proteins that bind to DNA
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20
Q

evidence for evolution - fossil records

A

fossil records show species getting more complex as time goes on, extinction and arrival of new forms - this evidence can be used to build phylogenic trees

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21
Q

problems with fossil records

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A
  • incomplete - fossils can only be formed under certain conditions - fossils can be destroyed easily
22
Q

evidence for evolution - biological molecules

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A

many biological molecules are found in all organisms - suggesting that all species arose from one common ancestor. closely related species have more similarities

23
Q

evidence for evolution - protein variation

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A

vital proteins are found in all living organisms, more change in these proteins = more evolutionary distance

24
Q

evidence for evolution - DNA

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A

sequencing in bases in DNA allows for comparison, the more differences found means there is greater evolutionary distance

25
adaptations
a feature that enhances survival and long-term reproductive success
26
a well-adapted organism should be able to:
- find enough food, water and mineral ions - defend itself - survive physical conditions of its environment - respond to changes in its environment - reproduce successfully
27
behavioural adaptation
an aspect of the behaviour of the organism that allows it to survive where it lives
28
example of behavioural adaptations
migration, hibernation
29
physiological adaptation
internal and biochemical features that ensure the correct functioning of cell processes
30
example of physiological adaptations
poison and antibiotic production
31
anatomical adaptation
any structure that enhances the survival of the organism
32
example of anatomical adaptations
camouflage, teeth
33
natural selection
- there is genetic variation in a population due to random mutations causing different alleles of genes - occasionally new alleles may be beneficial - there are selection pressure that mean that organisms have to compete for survival - some organisms will have advantageous characteristics - these are most likely to survive and reproduce to pass on alleles to offspring - this repeats over many generations so the beneficial alleles become more frequent in the population
34
how can pesticide resistance develop?
- insects may be able to metabolise the pesticide - target receptor proteins on the cell surface membrane may be modified
35
problems with pesticide resistance
- many insects carry diseases - pesticides become concentrated in the food chain and bioaccumulation can occur - crop loss - stronger pesticides may need to be used killing beneficial or benign insects - requires development of new pesticides - costly
36
gene pool
all the alleles of all the genes present in a population of interbreeding organisms
37
stabilising selection
the same alleles are selected for in every successive generation and the gene pool of the population remains roughly the same extremes of phenotypes are selected against
38
directional selection
an evolutionary force of natural selection one extreme will be selected against and the other will have a selective advantage over time the allele frequency shifts towards an extreme
39
genetic drift
random fluctuations occuring in allele frequency within a population purely by chance, in extreme cases alleles may be eradicated
40
genetic bottleneck
a natural disaster or disease may kill a larger percentage of a population this may lead to alleles being lost genetic diversity is reduced
41
founder effect
when a new population is started from only a few individuals, it may show a loss of genetic varation makes populations more vulnerable to environmental change
42
what reduces genetic variation?
- selective breeding - captive breeding - cloning - genetic bottlenecks - founder effect - genetic drift
43
monomorphic genes
all members of the populations have the same alleles of this gene
44
polymorphic genes
there are two or more alleles of a gene
45
proportion of polymorphic gene loci equation
proportion of polymorphic gene loci = number of polymorphic gene loci / total number of loci
46
how does speciation occur?
large populations can be split into sub-groups by isolating measures selection pressures may be different in each population or genetic drift may occur the gene pool of each population changes the two sub-groups may not be able to breed together and are not classifies as separate species
47
how does geopgraphical isolation cause speciation?
physical barriers can separate a population into two breeding groups different selection pressures will act on the two populations leads to different gene frequencies
48
what type of speciation is caused by geopgraphical isolation?
allopatric speciation
49
how does reproduction isolation cause speciation?
two groups of organisms may be isolated from breeding together even if they're in the same place ie due to different courtship behaviours, ecological barriers (organisms may rarely meet) or seasonal barriers (organisms active at different times of the day/year)
50
what type of speciation does reproductive isolation cause?
sympatric speciation
51
problems with artificial selection
reduces genetic diversity if environment changes, we may not have the gene pool to breed crops/livestock that can survive them characteristics selected for may cause health problems for the organism inbreeding often occurs increasing the chances of two recessive alleles coming together (inbreeding depression)
52
artificial selection solutions
breeders may decide to cross two different varieties to increase hybrid vigour gene banks may be created

ocr a level biology (9 decks)

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