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AS BIO UNIT2 > 2.1 Evolutionary History > Flashcards

2.1 Evolutionary History Flashcards

1
Q

What is taxonomy and who made it?

A
  • Carl Linnaeus
  • classified living things into groups based on obvious similarities ie morphology
    -larger groups then subdivided further to groups with even closer similarities
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2
Q

Define hierarchy

A

A system of ranking in which small groups are nested components of larger groups
- discrete and no overlap

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3
Q

What is the order of classification?

A

Delicious king prawn curry or fat greasy sausages

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4
Q

Explain the 3 domains

A
  • above the 5 kingdoms
  • bacteria, archea and eukarya
  • classified using rRNA sequences
  • Carl Woese
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5
Q

What methods are used to assess the relatedness of organisms for evolutionary trees?

A
  • morphology and biochemistry
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6
Q

Define homologous structures

A

Features that are very similar structures but serve different functions ie pentadactyl limb in vertebrates
- result of divergent evolution ( new species, similar structure )

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7
Q

Define analogous structures

A
  • example of convergent evolution where structures have evolved similar functions but have developed from a different origin
  • not an indicator of relatedness
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8
Q

What are the methods of assessing relatedness?

A
  • DNA sequences
  • DNA hybridisation - split DNA apart, DNA of two species mixed and allowed to reform so sequence hybridises
  • amino acid sequence - similar DNA sequences produce similar AA chain
  • immunology - mix antigens of one species with antibodies of another. More related = better ppt
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9
Q

Define and explain phylogenies

A
  • a natural classification system reflecting the evolutionary relationships between organisms
  • assumed all have common ancestor
  • look at fossils, DNA etc (biochem)
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10
Q

Explain the use of Cytochrome C in phylogeny

A
  • key respiration enzyme in nearly all organisms
  • conserved through generations - primary sequence does not change
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11
Q

Why do we need to classify?

A
  • infer evolutionary relationships
  • ease of communication via taxonomic group
  • conservationists judge the health of an ecosystem by counting families rather than individual species
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12
Q

Define sexual dimorphism

A
  • males and females look different
    ie male lions have mane, female do not
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13
Q

What is a reproductive way to determine if organisms are of the same species?

A

They will produce fertile offspring

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14
Q

Why is the binomial nomenclature used?

A
  • avoid confusion
  • Latin is universal language for science
  • prevent language miscommunication
  • enable to see relations based on genus
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15
Q

Define biodiversity

A

Measure of the number and variety of organisms found within a specified geographic region

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16
Q

23.5° north and south of the equator is where biodiversity is the most abundant. Why?

A
  • lots of rain due to LP systems and most concentrated solar incidence
  • enable more producers to live which supports higher tropic levels
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17
Q

Outline factors influencing biodiversity

A
  • habitat destruction
  • disease
  • predators
  • competition
  • pollution
  • climate change
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18
Q

Define an ecosystem

A
  • a group of interrelated organisms and their physical environment in an area that has fairly uniform conditions
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19
Q

Define population

A

All organisms of one species living in a particular environment

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20
Q

Define a community

A

All the organisms of all the species that live together in a particular ecosystem/habitat

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21
Q

What is richness and species evenness?

A

Richness : number of diff species
Species evenness : number of organisms within a species

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22
Q

How can biodiversity be measured?

A
  • qualitative survey
  • quadrats and transects
    —> animals: nets, pitfall traps, tullgren funnels
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23
Q

How many quadrats should be taken?

A

A minimum of 10

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24
Q

How can animal density be measured?

A
  • using Lincoln’s Index (mark, release, recapture)

Total pop = (c1x c2) / c3

C1: number in first capture
C2: number in second capture
C3: number marked in second capture

  • or Simpsons diversity index ( higher val = higher biodiversity)
25
Q

Gene locus

A

Position of a gene on a chromosome

26
Q

Genotype

A

Genetic constitution of an organism (allele combination)

27
Q

Phenotype

A

Physical expression of the genotype

28
Q

Allele

A

Different versions of the same gene

29
Q

Define polymorphism

A

Occurrence of more than one phenotype in a population with the rarer phenotypes at frequencies greater than can be accounted for by mutation alone
- higher polymorphism = higher biodiversity

30
Q

How can alleles indicate biodiversity?

A

More equal properties of different alleles mean higher biodiversity

31
Q

On a molecular level, how can individuals vary from one another?

A
  • non coding DNA sequences undergo mutations
32
Q

What is it called when only one base sequence in DNA differs?

A

SNPs (single nucleotide polymorphins)

33
Q

What is it called when regions of DNA differ?

A

HVRs ( hyper variable regions ) or STRs ( short tandem repeats )

34
Q

What is DNA profiling?

A

A technique used by scientists to distinguish between individuals of the same species using only their DNA
- comparison of the number and position of bonds

35
Q

The more SNPs/HVRs a population has …

A

The more variation and therefore the greater biodiversity

36
Q

How does DNA profiling work?

A
  • take sample of tissues/cells
  • add restriction endonucleases (enzymes that cut DNA at a certain locus)
  • sample put onto gel and sometimes into wells
  • sample diffuse through gel at a rate related to size
  • DNA travel to positive electrode due to its overall negative charge
37
Q

Define natural selection

A

The gradual process in which inherited characteristics become more or less even in a population
—> determines breeding success of organisms as evolved are able to reach reproductive age and pass on alleles

38
Q

Darwin’s theory of NS, steps

A
  1. Mutation
  2. Variation
  3. Competitive advantage
  4. Survival of fittest
  5. Reproduction
  6. Pass advantageous alleles to offspring
39
Q

What are some observations of natural selection?

A
  • offspring generally appear similar to parents
  • individuals of a species all born with slight variation
  • often larger numbers of offspring but many die before reproduction
    —> disease, predators, competition
  • population sizes in nature tend to remain fairly stable
40
Q

Define divergent evolution

A

Development of different structures over long periods of time from the equivalent structures in related organisms

41
Q

Define convergent evolution

A

Development of similar features in unrelated organisms over long periods of time, related to NS of similar features in a common environment

42
Q

Explain what the 3 domains are

A

Bacteria: prokaryotes
Archaea: bacteria, many extremophiles
Eukaryote: plantae, animalia, fungi and protocista

43
Q

Taxonomy

A

The identification and naming of organisms

44
Q

Why is biological classification tentative

A

Can change as more info becomes available

45
Q

Disease caused by prokaryote, protocista and fungi

A

Prokaryote - E. coli
Protocista - malaria
Fungi - athletes foot

46
Q

Apart from DNA what other molecule can assess relatedness?

A

Protein

47
Q

How can DNA profiling determine most closely related species?

A

Most bands or sequences in common

48
Q

Define species

A

Group of organisms w similar characteristics that can interbreed and produce fertile offspring

49
Q

Define an ectoparasite

A

An organism that lives on the surface of another organism and feeds on the host to obtain nutrients, but harms the host in doing so

50
Q

Animalia kingdom

A
  • eukaryotic and multicellular
  • heterotrophic
  • nervous coordination
51
Q

Protocista

A
  • eukaryotic
  • heterotrophic and photosynthetic
  • unicellular
  • no tissue differentiation
52
Q

Fungi

A
  • heterotrophic eukaryotes
  • chitin
  • saprotrophic
  • do not photosynthesise
53
Q

In kick sampling, suggest why values obtained can be less than the actual

A
  • animals not caught by net
  • animals not dislodged from stream bed
  • uneven kicking
  • animals too small to identify
54
Q

Define adaptive radiation

A

Formation of a new species in response to environmental changes from a common ancestor

55
Q

3 types of adaptations

A
  • behavioural
  • physiological / biochemical
  • anatomical
56
Q

How does DNA hybridisation allow relationships between species to be determined

A
  • for the 2 most related species, the base sequences will be more similar and more complimentary
  • more hydrogen bonds will form so will have highest separation temperature
57
Q

Define a domain

A
  • organism that share a distinctive, unique rRNA pattern which establishes their close evolutionary relationship
58
Q

Technique used to compare amino acid composition and how it has improved classification

A
  • electrophoresis
  • reduces mistakes due to convergent evoltuion

AS BIO UNIT2 (7 decks)

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