1. No category

LE­#29­Natural Selection and Evolution.notebook
Lamarck
Darwin
General Idea:
If an organism changes during life in order to adapt to its environment, those changes are passed on to its offspring. He said that change is made by what the organisms want or need.
Modern Theory = General Idea:
He said that organisms, even of the same species, are all different and that those which happen to have variations that help them to survive in their environments survive and have more offspring. The offspring are born with their parents' helpful traits, and as they reproduce, individuals with that trait make up more of the population. Other individuals, that are not so well adapted, die off.
+
Apr 23­7:28 AM
Disproving Lamarck:
August Weismann
Apr 23­8:42 AM
LE­#29­Natural Selection and Evolution.notebook
1. Who is Charles Darwin?
(1809­1882)
http://www.sciencechannel.com/video­topics/earth­science/galapagos­beyond­darwin­charles­darwin.htm
Apr 23­7:32 AM
2.Natural Selection
*Darwin's thinking: if humans could artificially select for certain traits, why can't nature?
* Over time, the average height of sunflower population is short if the short sunflowers continue to reproduce more successfully. After many generations, the short sunflowers may become a new species if they are no longer able to breed with the original sunflowers.
Apr 23­7:40 AM
LE­#29­Natural Selection and Evolution.notebook
*Darwin's On the Origin of the Species:
natural selection = evolution
natural selection is a way to explain how evolution works!
YOU DO NOT DEVELOP ADAPTATIONS BECAUSE YOU NEED THEM. YOU CAN NOT PASS ON ACQUIRED CHARACTERISTICS!
http://www.animalplanet.com/wild­animals/animal­adaptations/
https://faculty.washington.edu/chudler/amaze.html
http://www.exploringnature.org/db/detail_index.php?dbID=5&dbType=2t
Apr 23­7:42 AM
Apr 23­7:42 AM
LE­#29­Natural Selection and Evolution.notebook
Apr 22­8:55 AM
4. Evidence for Evolution
Comparative Anatomy
https://www.khanacademy.org/partner­content/crash­course1/crash­course­biology/v/crash­course­biology­120
Apr 23­7:42 AM
LE­#29­Natural Selection and Evolution.notebook
Apr 23­7:47 AM
4. Evidence for Evolution
Vestigial Structures
Apr 23­7:47 AM
LE­#29­Natural Selection and Evolution.notebook
4. Evidence for Evolution
Comparative Embryology
Apr 23­7:48 AM
4. Evidence for Evolution
Comparative Biochemistry
Cytochrome c (cellular respiration)
Hox genes
Apr 23­8:35 AM
LE­#29­Natural Selection and Evolution.notebook
General Definition of Evolution:
Change in species over time
What you should know about evolution:
• Individuals DO NOT evolve, only species over a long period of time
• Individuals DO NOT become extinct, only species become extinct
• "Fitness" is determined by the ENVIRONMENT; what is fit in one environment, may not necessarily be fit in another
• Evolution is going on today..... example: antibiotics and antiviral drugs are becoming ineffective because bacteria and viruses are mutating, becoming resistant, and therefore carrying on evolution.
Apr 23­8:40 AM
Divergent­Adaptive Radiation­
common ancestor evolves into different adaptations
Parallel
a similar trait in related, but distinct, species descending from the same ancestor
5. Types
of Evolution
Convergent
organisms not closely related evolve similar traits as a result of having to adapt to similar environments
Apr 23­7:52 AM
LE­#29­Natural Selection and Evolution.notebook
Gradualism vs. Punctuated Equilibrium
Apr 23­7:53 AM
Apr 23­7:55 AM
LE­#29­Natural Selection and Evolution.notebook
Reproductive Isolation
Geographic Isolation
Speciation
http://ed.ted.com/on/R4PiqPn1#digdeeper
Geographic Isolation­ organisms separated by geography (islands, mountains, changed river course, etc.)
Reproductive Isolation­ organisms reproduce with other organisms in the same area
Speciation­ Different adaptations produce new species (species must reproduce fertile offspring)
Geographic Isolation Reproductive Isolation Speciation
Apr 23­9:34 AM
Conditions Necessary for Hardy­
Weinberg Principle
Relationship to Evolution
1 No mutations
1
mutations ­ Adaptations ­ Natural selection
2 No Natural Selection
2
NS­ mechanism for how
evolution works
3 Population must be very large
3
overproduction → produce more than can survive, so there's a better chance for survival
4 Mating must be totally random
4
Sexual selection­ mates choose based on best "fit" (strongest, mating calls, bright colors, pheromones, etc.)
No migration into/out of the 5
Migration ­ brings new genes into a population
5 population
Apr 23­7:55 AM