Ch. 15 Evidence for Evolution

Question 1

What are the 3 evidence for evolution

Answer 1

comparative biocehm, anatomy and fossil

Question 2

what are the 4 areas of biochem comparison

Answer 2

• DNA
• Junk DNA
• Mitochondrial DNA
• Protein Sequences

Question 3

what are the 3 areas of anatomical comparison

Answer 3

• Embryology
• Homologues Structures
• Vestigial Organs

Question 4

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

Answer 4

common ancestor

Question 5

how is speciation evidence for evolution

Answer 5

• 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

Question 6

How are genes gained or lost

Answer 6

New genes gained by mutation

Genes lost by natural selection, genetic drift etc.

Question 7

define junk DNA

Answer 7

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

Question 8

Explain endogenous retrovirus as evidence of evolution

Answer 8

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

Question 9

what has comparing dna strands of different species suggest

Answer 9

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

Question 10

what is the rate of mutation of mtDNA show

Answer 10

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

Question 11

what has comparing mtDNA allowed

Answer 11

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

Question 12

How are degree of similarities show with protein sequences

Answer 12

• 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

Question 13

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

Answer 13

o greater number of amino acids that are different

- Amino acids represented by a three letter code

Question 14

define ubiquitous proteins

Answer 14

>

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

Question 15

what does all ubiquitous proteins have in common

Answer 15

♣ 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

Question 16

what is cytochrome c an example of

Answer 16

ubiquitous protein

Question 17

what was the human genome project

Answer 17

• 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

Question 18

what techniques are used to help compare

Answer 18

bioinformatics and comparative genomics

Question 19

define embryology

Answer 19

comparing the very early stages of the development of organisms

Question 20

define homologous structures

Answer 20

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

Question 21

define vestigial organs

Answer 21

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

Question 22

what are 5 common features of embryos

Answer 22

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

Question 23

why are gill slits important

Answer 23

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

Question 24

whats another piece of evidence that supports we came from fish

Answer 24

♣ 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

Question 25

what is embryology evidence for

Answer 25

common ancestry with later evolution along different pathways

Question 26

whats an example of homologous structures

Answer 26

forelimbs of vertebrares

Question 27

how does evolutionary mechanisms explain vestigial organs

Answer 27

• 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

Question 28

what is the effect of natural selection of vestige organs

Answer 28

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

Question 29

what are 8 examples of vestigial organs in humans

Answer 29

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

Question 30

explain the vestigial organ of muscles at base of hairs

Answer 30

• 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

Question 31

define isolated areas

Answer 31

evolved their own distinctive plant and animal populations

Question 32

define geographical distribution

Answer 32

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

Question 33

what are three examples of geogrpahical distribution

Answer 33

australia galapogs islands and primates