*III. The Red Queen Effect- "The Evolutionary Arms Race"
          Predators and prey, competitors and the Environment are constantly driving the evolution of its/their "partners". Perfection is impossible.
IV. Adaptations are Compromises- most adaptations will be good and bad. Giraffes neck, seals (bad on land, good in water), etc.
V. Genetic Limitations- DNA can only take a population so far. It can only use the alleles that are present now.
VI. 99% Extinction
VII. Not all evolution is adaptive- 5 forces
      Only Natural Selection is adaptive
     

Does evolution always make a population better? Can it ever acheive perfection?

Does evolution always make a population better? Can it ever achieve perfection?

NO! Evidence:

• Sexual Selection - Finding and attracting a mate takes precedence over their survival. For example: Peacocks,  Elk
• Fecundity>Longevity -Passing down genes has more effect on evolution than living a long life. For example: Salmon. Born in a sterile environment then move and become "eating machines". They produce enough fat to travel back to where they were born. When traveling back upstream they stop eating because they HAVE to die for their species. Their bodies produce nutrients for the food that the babies can live on for a short period of time.

IV. Gene Flow- Migration
     A. Immigration- movement into a population (adds alleles)
     B. Emigration- movement out of a population (subtracts alleles)
V. Non-Random Mating
     A. Inbreeding- tendency to mate with an individual more closely related. Increases p^2 and q^2 (AA&aa) and decreases 2pq (Aa)
     B. Outbreeding- tendency to mate with an individual less closely related.
     C. Assortative Mating- tendency to mate with one's own morph."look" >q^2 <p^2+2pq

      

5 Forces Continued

II Mutation- point mutations will add "new" alleles to a population. Insignificant in the short term. The #1 most important in the long term.
III. Natural Selection- an allele, or genotype, is favored by the environment.
    3 basic types:
               A. Directional- when one "extreme" is forced over the other. Example: a giraffes neck
               B. Stability - the average is favored over extremes. Example: deer population: bucks with big         antlers are killed in hunting season and small bucks don't breed, so the antler size left are the middle size. this is BAD. Humans are predators
               C. Disruptive: when the average is selected out of the population: GOOD. also known as frequency dependent selection: individual with the more common traits are selected out of the population. Example: Trout eat the flies that are most common. Animal are predators

5 Forces that Disrupt the H/W Equilibrium:

-Remember, a population will remain unchanged unless an outside force acts on them.

Tongue rolling

 -2003
TR = .75 A_
NTR = .25 aa

-2013
TR = .80 A_
NTR = .20 aa

What force changed this? Was it just chance?

I. Genetic Drift - allele/gene frequencies change by chance in a population.
This is more likely to happen in a SMALL population. There are 2 events
that will promote genetic drift:
A. The Founder Effect - when a small number of individuals migrate away and become genetically isolated. A small amount of individuals have many descendants. ex. Amish
B. Population  Bottleneck - when a large population is reduced down to very small size. ex. Blackfooted ferret, cheetah
  

How is genetic variation preserved and potentially even promoted in a population?

I. Diploidy - For every gene there are (at least) two copies because almost every species on the earth currently is sexually reproducing. What does this do for us?
     A. Allows recessives to exist. (Example: white skin. Dark skin is very common among people along the equator. This prevents skin cancer from the sun but when our ancestors moved out of Africa, we developed light skin because we didn't have to worry about skin cancer as much and light skin allows us to absorb the sun and make our own Vitamin D.)
     B. Allows codominance. (Example: African people want to be heterozygous for Sickle Cell Anemia because the recessive protects against Malaria. This could not happen without Diploidy.)

II. Meiosis
     A. Crossing Over - It is the number 1 factor for genetic variation in gametes.
     B. Independent Assortment - the number 2 factor for genetic variation - two chromosomes separating do not affect each other (flipping two coins). This exponentially magnifies the variation from crossing over.

III. Sexual Reproduction
     A. Two parents' genetic info is randomly passed to offspring. (You are not the same as your siblings.)
     B. Mechanisms that promote outbreeding. (the opposite of inbreeding - we think marrying our cousins is gross and flowering plants promote outbreeding because they attract pollenators.)

IV. Clines - Happens when a population's genetics change from one side of its range to another.

V. Ecotype - genetic variation types of the same species because they live in different ecosystems.

II. Darwin's Theory
A. All populations are genetically variable.  "New" variations can suddenly appear within a population.  These variations can be passed to the offspring.
B. (Thomas Malthus)  All populations will eventually reach a size where "more offspring are born, than can survive to breeding age."
C. A competition will occur between individuals for limited resources.
D. The environment selects those individuals best adapted to survive and pass on their genes. Natural Selection.

III. Comparative Anatomy cont...
C. Vestigial Structures: are of no apparent use or value. remnants of our evolutionary past?
IV. Comparative Embryology
Ontogeny Recapitulates Phylogeny
The development of embryo is a highlight reel of the evolution of that species.
V. Physical Sciences
A. Astronomy: The farthest galaxy identified is approximately 15 billion light years away from the earth (Light Year: amount of distant light travels in a year)
B. Geology: slowly but surely, geologic forces (erosion, tectonics, volcanism) cause great change over long periods of time.
Gradualism
VI. Artificial Selection:when humans breed for characteristics that we select and the result is great change in a species. DOGS
VII. Biogeography: where life is located on the planet
 A. Isolation=Endemism (found in only one place) When a population becomes isolated, mutation and natural selection will start to change population and make it different from its ancestral species. If the isolation lasts long enough, a new species will evolve.

01/08/13

(We finished up the cladogram of the vertebrates. I'm not sure (depending on which hour you're in) if you have this cladogram finished. 4th hour did not. So check with a neighbor. Below is the part of the cladogram on hearts, which Lit said would be on the test. Pictures came with it.)

Fish                                   Amphibians              Reptiles                        Birds                        Mammals
2-Chambered (50%)       2 then 3 (70%)     3, Ventrical paritally            4   (100%)                4 (100%)
                                                                         divided  (85%)    

~~~

II. Comparative Biochemistry--Comparing the sequences of DNA & Proteins. Allows us to determine genetic relationships between organisms.

III. Comparative Anatomy 

   A. Homologous Structures--Similar anatomically, but not necessarily similar functionally. Allows us to see

          Divergent Evolution--the structures become dissimilar functionally. 

   B. Analogous Structures--similar functionally but not similar anatomically. Evidence of Convergent

             Evolution--two "unrelated" species develop functionally similar structures from different origins.

There are 4 extraembryonic (made up of embryonic tissue but not actually part of the embryo proper) membranes that are found in all amniotic organisms:

Membrane........................Function in Egg Layers.................Function in Placentals

AMNION.......................Forms a sac around the ....................same
........................................embryo and fills w/ fluid

CHORION........................gas exchange mechanism..................placenta
..........................................just beneath shell

ALLANTOIS.....................forms a waste sac.............................umbilicus

YOLK SAC......................surrounds the yolk.............................vestigial

Fossil- any evidence of former life. (species that are no longer present)
(e.g. petrified wood, fossilized bones, insects preserved in amber etc.)
I. Fossil Record
 B. >99% Extinction- or 99% or higher number of species of organisms should be extinct.
C. Fossils found "where they shouldn't be." Like fossils of marine animals on mountain peaks.
D. Fossils laid down in order from simple to complex. (bacteria fossils-simple aquatic animals-fish-land plants-amphibians-reptiles-dinosaurs-mammals-birds)
E. History of our planet.
Cladogram of the Vertebrates( Animals with spinal columns) This shows how animals are connected, evolutionary speaking (fish to reptiles to birds and also reptiles to mammals. Mammals came before birds.)
 1 Fish       2 Amphibians        3 Reptiles      5 Birds       4 Mammals
     i              i                        i                    i                  i
      i              i                iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
         i          i  i               
               i    
Note: the i's don't really mean anything they just connect the animals)
Fish-Ectothersm (require an outside source of heat to function), have fish scales, external fertilization, gelatinous eggs.
Amphibians- Ectotherm, no body covering, external fertilization, gel eggs.
Reptiles-Ectotherm, have reptile scales (very different from fish scales, internal fertilization, amniotic (shell wtih amniotic fluid  surrounding the embryo) egg.
Birds-Endotherm (generate heat from the inside), have feathers, and scales (think of a birds feet), internal fertilization, amniotic egg.
Mammals-Endotherm, have hair, internal fertilization, Amniotic eggs (not very many, like platypuses, and echidnas nowadays), Marsupials-kangaroos, koalas, and other mammals with pouches (embryos of marsupials have a yoke while they are in the mother), and Placental mammals(all of the other mammals).