Ch. 15 Evidence for Evolution Flashcards

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1
Q

What are the 3 evidence for evolution

A

comparative biocehm, anatomy and fossil

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2
Q

what are the 4 areas of biochem comparison

A
  • DNA
  • Junk DNA
  • Mitochondrial DNA
  • Protein Sequences
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3
Q

what are the 3 areas of anatomical comparison

A
  • Embryology
  • Homologues Structures
  • Vestigial Organs
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4
Q

What is the fact that all living things have same DNA code provide evidence for

A

common ancestor

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5
Q

how is speciation evidence for evolution

A
  • Although all species have DNA, sequences very
  • Speciation: when it occurs (ancestral species= 2/+ species) new species= similar DNA
    o As species changes, accumulate more differences
    o Close related species= share greater proportion of DNA
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6
Q

How are genes gained or lost

A

New genes gained by mutation

Genes lost by natural selection, genetic drift etc.

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7
Q

define junk DNA

A

Non-coding sequences of bases in DNA, no apparent function

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8
Q

Explain endogenous retrovirus as evidence of evolution

A

o Viral sequence that has become part of the organism’s genome
o Store genetic info as RNA > enters cell > copies RNA into DNA (reverse transcription) > DNA inserts into one of its hosts cell’s chromosomes
o If inserts into gamete= offspring inherit in same place, same chromosome
o // common ancestor

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9
Q

what has comparing dna strands of different species suggest

A
  • increase genetic distance b/w humans + other primates= indicate all these animals once shared a common ancestor, diverging at different points
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10
Q

what is the rate of mutation of mtDNA show

A

o Amount of mutation roughly proportional to amount of time has passed
o Scientists use similarity b/w mtDNA of any two individuals to provide estimated closeness of their relationship through maternal ancestors
o // if mtDNA is very different their last common ancestor lived a long time ago

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11
Q

what has comparing mtDNA allowed

A

o Allowed scientists to track ancestry and trace migration routes of ancient people
o Also been used to demonstrate the evolutionary relationships between humans and closely related species
o Important tool in mapping relationships b/w species

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12
Q

How are degree of similarities show with protein sequences

A
  • Comparing type and sequence of amino acids in protein from different species= degree of similarity can be established
    o Animals of same species= identical sequences
    Different species= different amino acids or arranged in different order
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13
Q

in terms of protein sequences, what occurs the longer period of time involved

A

o greater number of amino acids that are different

- Amino acids represented by a three letter code

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14
Q

define ubiquitous proteins

A

>

One of a group of proteins that appears to be in all species form bacteria to humans
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15
Q

what does all ubiquitous proteins have in common

A

♣ perform basic but essential tasks that all organisms require for life
♣ Found in all organisms
♣ Completely independent of an organisms specific function or the environment in which it lives
♣ Carry same function no matter where found

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16
Q

what is cytochrome c an example of

A

ubiquitous protein

17
Q

what was the human genome project

A
  • 2003 demonstrated that major sequencing projects can generate high quality data // interest in sequencing of genomes of species increased
  • By analysing genomic features that have been preserved in a number of species over millions of years, can begin to tease apart subtle differences b/w animal species
  • Comparative genomics= revealed
    o high number of similarities between closely related organisms
    o the diversity of gene composition in different evolutionary lineages
18
Q

what techniques are used to help compare

A

bioinformatics and comparative genomics

19
Q

define embryology

A

comparing the very early stages of the development of organisms

20
Q

define homologous structures

A

organs that are similar in structure but are used in different ways

21
Q

define vestigial organs

A

organs that may once have been important but have lost or changed their function

22
Q

what are 5 common features of embryos

A
o	Gill slits and pouches 
o	Absence of paired appendages 
o	Presence of well-developed tails 
o	Two chambered heart
o	Similar brain development
23
Q

why are gill slits important

A
  • vertebrates are views as an evolutionary series that began with fish
    o Overtime= evolutionary divergence into amphibians> reptiles> birds > mammals
24
Q

whats another piece of evidence that supports we came from fish

A

♣ Humans= one of the embryonic gill slits develops into the Eustachian tube, and tissue surrounding other gill slits develops into the thyroid gland and tonsils

25
Q

what is embryology evidence for

A

common ancestry with later evolution along different pathways

26
Q

whats an example of homologous structures

A

forelimbs of vertebrares

27
Q

how does evolutionary mechanisms explain vestigial organs

A
  • They are what remains of organs that were functional in ancestral forms
  • Over time + changing environmental conditions= organs no longer essential to survive and were gradually reduced to vestigial remnants
  • Not harmful // not been completely eliminated
28
Q

what is the effect of natural selection of vestige organs

A

o = waste of organism’s energy and resources to maintain useless structure
o Such organs will probably disappear altogether as no selection pressure to retain them

29
Q

what are 8 examples of vestigial organs in humans

A
nicitating membranes 
muscles that move ears
third molars 
pyramidalis musles
tail vertebrae 
appendix 
male nipples
muscles at base of hairs
30
Q

explain the vestigial organ of muscles at base of hairs

A
  • In mammals with fur or spines, and birds with feathers, tiny muscles pull the hair or feather upright, creating layer of insulating air to protect against cold
  • However, in humans= hair so fine it is not capable of the function and the contraction of the muscles is seen as Goosebumps
31
Q

define isolated areas

A

evolved their own distinctive plant and animal populations

32
Q

define geographical distribution

A
  • the natural arrangement and apportionment of the various forms of animals and plants in the different regions and localities of the earth
33
Q

what are three examples of geogrpahical distribution

A

australia galapogs islands and primates