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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
Gene locus
Position of a gene on a chromosome
26
Genotype
Genetic constitution of an organism (allele combination)
27
Phenotype
Physical expression of the genotype
28
Allele
Different versions of the same gene
29
Define polymorphism
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
How can alleles indicate biodiversity?
More equal properties of different alleles mean higher biodiversity
31
On a molecular level, how can individuals vary from one another?
- non coding DNA sequences undergo mutations
32
What is it called when only one base sequence in DNA differs?
SNPs (single nucleotide polymorphins)
33
What is it called when regions of DNA differ?
HVRs ( hyper variable regions ) or STRs ( short tandem repeats )
34
What is DNA profiling?
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
The more SNPs/HVRs a population has …
The more variation and therefore the greater biodiversity
36
How does DNA profiling work?
- 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
Define natural selection
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
Darwin’s theory of NS, steps
1. Mutation 2. Variation 3. Competitive advantage 4. Survival of fittest 5. Reproduction 6. Pass advantageous alleles to offspring
39
What are some observations of natural selection?
- 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
Define divergent evolution
Development of different structures over long periods of time from the equivalent structures in related organisms
41
Define convergent evolution
Development of similar features in unrelated organisms over long periods of time, related to NS of similar features in a common environment
42
Explain what the 3 domains are
Bacteria: prokaryotes Archaea: bacteria, many extremophiles Eukaryote: plantae, animalia, fungi and protocista
43
Taxonomy
The identification and naming of organisms
44
Why is biological classification tentative
Can change as more info becomes available
45
Disease caused by prokaryote, protocista and fungi
Prokaryote - E. coli Protocista - malaria Fungi - athletes foot
46
Apart from DNA what other molecule can assess relatedness?
Protein
47
How can DNA profiling determine most closely related species?
Most bands or sequences in common
48
Define species
Group of organisms w similar characteristics that can interbreed and produce fertile offspring
49
Define an ectoparasite
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
Animalia kingdom
- eukaryotic and multicellular - heterotrophic - nervous coordination
51
Protocista
- eukaryotic - heterotrophic and photosynthetic - unicellular - no tissue differentiation
52
Fungi
- heterotrophic eukaryotes - chitin - saprotrophic - do not photosynthesise
53
In kick sampling, suggest why values obtained can be less than the actual
- animals not caught by net - animals not dislodged from stream bed - uneven kicking - animals too small to identify
54
Define adaptive radiation
Formation of a new species in response to environmental changes from a common ancestor
55
3 types of adaptations
- behavioural - physiological / biochemical - anatomical
56
How does DNA hybridisation allow relationships between species to be determined
- 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
Define a domain
- organism that share a distinctive, unique rRNA pattern which establishes their close evolutionary relationship
58
Technique used to compare amino acid composition and how it has improved classification
- electrophoresis - reduces mistakes due to convergent evoltuion

AS BIO UNIT2 (7 decks)

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