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Bio - Evolution

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Teresa Friedrichsen

on 23 August 2016

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Transcript of Bio - Evolution

ii. Overproduction of offspring -
"The phrase 'survival of the fittest' really relates to individuals rather than to populations.  Natural selection is a process in which the fittest organisms survive and reproduce, creating a population with these qualities necessary for survival."
Lindsey Nestor class of 2014
Bottleneck Effect
When the beetles reproduced, just by random luck more brown genes than green genes ended up in the offspring. In the diagram at right, brown genes occur slightly more frequently in the offspring (29%) than in the parent generation (25%).
iv. Populations evolve, not Individuals!
Genes determine phenotype; therefore an individual cannot “decide” to change its phenotype to adapt
iv. Differential Survival & Reproduction
Changing environment (including predators) can affect which organisms survive
Best adapted individuals who survive will also leave offspring
examples: claws, speed, sharp teeth, stingers, thorns, quills, mimicry & camouflage, bad smell, bad taste, venom
http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_30
Observed & practiced Artificial Selection- Humans select the traits in plants or animals that they want reproduced.
Large population
No mate preference – all phenotypes equally attractive
No change in allele frequency if …
All phenotypes equally adapted to environment
No mutation
No immigration or emigration
Strongest males must win fight over other males so that they can mate with females
Founder Effect
large population is drastically reduced by some EVENT
Allele frequency increases or decreases due to chance - not whether organism is adapted to environment or not
Smaller the population, the greater the change
organisms move from one population to another
Immigrants bring new genes to gene pool
Emigrants remove genes from gene pool
What can cause microevolution in this population?
What natural selection is
i. It results in "good enough" not in perfect organisms
ii. It is a process; there is no direction or goal involved (unless God directs it)
http://nre509.wikidot.com/midterm-exam-2-notes
Stabilizing selection favors average individuals in a population – both extremes die
http://www.utm.edu/departments/cens/biology/rirwin/391/391quantevol.htm
Types of NS
Adapted from the University of California, Los Angeles Life Sciences 1 Demonstration Manual
Copyright 2006 by Jennifer Doherty and Dr. Ingrid Waldron, Department of Biology, University of Pennsylvania
http://biology.clc.uc.edu/graphics/bio106/nat-sel.jpg
iii. Adaptations help in struggle to survive
Some traits affect how well adapted an organism is and whether it will survive
Traits in Normal distribution
http://www.mnsu.edu/emuseum/biology/evolution/images/bellcurve.gif
i. Variation
All offspring are different from one another
Most variations are genetically inherited
Recombination of alleles & mutations are sources of variation
“a natural process that results in the survival and reproductive success of individuals or groups best adjusted to their environment and that leads to the perpetuation of genetic qualities best suited to that particular environment."
Charles Darwin
1809 - 1882
what causes change in allele frequency of gene pool? …..
change in allele frequency in gene pool over time
http://www.brooklyn.cuny.edu/bc/ahp/LAD/C21/graphics/C21_GenePool_2.GIF
Microevolution
Small changes within a species
http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_37
Change in DNA - point or chromosomal
Can be good (rare), bad (frequent), or neutral
Only source of new genes!
iii. “Need” does not trigger natural selection
characteristics or adaptations must be present in order to be selected- they can’t just come out of “thin air”.
http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_32
Dull and brightly colored males fathered more chicks than males with intermediate color
In disruptive selection, individuals with either extreme of a trait’s variation are selected for – average trait dies
http://www.abc.net.au/science/articles/2000/10/27/204407.htm
Goldenrod forms gall when gall fly lays egg in stem- egg hatches into larvae inside gall: bigger larvae results in bigger gall
Naturalist on a research ship to Galapagos Islands
Wrote Origin of Species
Believed that new species evolved by natural selection
http://www.windows.ucar.edu/tour/link=/earth/Life/images/gene_pool_lg_gif_image.html
Gene Pool
the total of alleles from every individual in the population
Directional selection favors one of the extreme variations of a trait – other extreme & average trait dies
Normal
variation
Selection for longer beaks
4
3.5
3
2.5
2
1.5
1
0.5
present
1.2 1st eukaryotic cells
3.2 1st prokaryotic cells
0.3 plants, amphibians, reptiles
0.7 marine invertebrate, fish, algae, fungi
0.25 dinosaurs, birds, insects
cyanobacteria produce oxygen during PS
Macroevolution
speciation
gene pool
mechanisms of evolution
no evolution
darwin
natural selection
great tree of life: 11 min
Ted Ed: 5 fingers of evolution: 5 min
whale evolution: 1.5 min
how natural selection works (hummingbirds): 7 min
birds of paradise
reproductive isolation
behavioral barriers
geographic barriers
temporal barriers
change that occurs at or above the level of species
evidences of evolution
genetic drift: chance
non-random mating: sexual selection
mutation
gene flow: movement or migration
evolution
Females choose to mate with most conspicuous males
small number of individuals from large population colonize a new area with no other organisms!
combined alleles of all individuals in a population
individuals that can mate in wild & produce fertile offspring
Evolution
fossils
embryology
biogeography
anatomy
molecular
record of early life including extinct species
incomplete record - only those organisms that die & are covered quickly will fossilize
transitional species or missing links: some still missing
homology
vestigial
visualizing change through the lenses of
forming new species
Example: polar bear only in Arctic & penguins only in Antarctica
Similar structures result of Common ancestor
Example: bat wing, human arm, cat leg, whale flipper

a. Homologous structures
SPECIES Y
SPECIES X
iii. Result of Divergent Evolution
Different environments
SAME
ANCESTOR
Similar structures a result of similar selective pressures, not a common ancestor
Example: Bird & insect wing
b. Analogous Structures
Similar environment
ANCESTOR Z
ANCESTOR Q
iii. Result of Convergent Evolution
SPECIES Y
SPECIES X
Do sharks & dolphins have similar features due to analogy or homology?
Organs with no apparent functions that are leftovers from previous ancestors.
Related organisms go through similar embryonic development
Homeobox genes code for proteins that trigger patterns of development– like placement of head, eyes, legs, tail, etc.
Pseudogenes- no longer functional, but still in genome
Gene comparisons
http://www.life.uiuc.edu/bio100/lectures/fall97lects/cladogram.GIF
more similar, more closely related
DNA comparisons -
More similar, the more closely related
Protein comparisons
when members of populations can no longer successfully mate with one another
different mating behaviors
different mating times
physical or geographical
Whale evolution
Ancestors move to different environments and change into many species due to different selective pressures

Adaptive radiation or divergent evolution
NS extrapolated
cladograms
New species evolve when isolated populations diverge into new environments
Continued divergence over long time form higher taxa
Conclusion
large changes in genetic variation
large changes in environment

Changes in developmental timing
feathers first had to have been used for something other than flying - like stability, or show, or catching prey
“The adult Mexican axolotl resembles a juvenile form of a possible ancestor because it retains the feathery gills that related species lose in infancy.”
Preadaptation
existing structure used for a new purpose
changes in location of main body parts - Homeobox genes
continental drift
change in growth rates
mass extinctions
volcanic action
due to plate tectonics
Branching diagram or tree that shows relative amount of evolutionary relatedness among organisms
New characteristic or derived trait
Common Ancestor
For Y, & Z
X Y Z
Common
Ancestor
For X, Y, & Z
The New Critters- find 8 characteristics that differ
http://www.amnh.org/exhibitions/hall_tour/spectrum/graphics/cladogram.gif
inference (guess) starting with what is known and expanding to what is unknown
extrapolation
A
B
C
D
E
F
A
B
C
D
E
F

12 min overview
9 min bozeman
9 min black & white mice
18 min anoles
why would shrinking dinosaur size be advantageous?
9 min stated clearly
11.5 min whale evidence
variation + selection + time
more are produced than can survive which leads to competition
Key Principles
analogy
Cladogram
Geography affects where organisms are living over long periods of time
billion years ago
billion years ago
Similar environments in different parts of the world DO NOT have similar plants & animals - but islands near mainlands DO!
Example: marsupials almost all in Australia
parasitic wasp kills small larae
woodpecker kills large larvae
1min
15 min crash evo history
7 min amoeba sisters
4 min myths & misconceptions
LUCA
History of Life on Earth
2 min evolution in 24 hours
6.5 min tree of life
horse + donkey = mule
64 + 62 = 63 chromosomes
3:13-4:56 branching bunnies
show 10:09 - end homeobox genes
14 min genes control segmentation
closely related species live in areas that are geographically close to one another - or used to be close to one another
study of distribution or migration of organisms
3 min 99% similar to chimps
3 min why hybrid animals are sterile
3.5 min mass extinctions
Full transcript