Evidence for Evolution on Earth Fossil Record – transitional fossils Comparative Anatomy – homologous, analogous, vestigial Comparative Embryology Comparative Biochemistry Geographic Distribution
Evidence From Fossils Analogous Structures Homologous Structures Vestigial Structures – some bird wings; snakes and whale hips/pelvic girdle
Transitional
Embryological Evidence
Biochemical Differences
Continental drift Earth’s continents have moved during Earth’s history and are still moving today at a rate of about six centimeters per year. The theory for how the continents move is called plate tectonics. http://www.youtube.com/watch?v=GYVS_Yh6dTk 7
2 Types of Evolution Microevolution Small scale Macroevolution Large scale To understand this better, you must know what a species is: One group of interbreeding organisms found in one place at one time.
Microevolution Small scale evolution occurring over a relatively short period of time = changes within one population Produces “ecotypes” or ecological races. Examples: differences in eastern and western bird species color, orcas, etc. Includes 4 topics Mutation Selection Gene Pool Genetic Drift
Macroevolution Large-scale evolutionary patterns and processes that occur over long periods of time = speciation (making a new species) Includes 6 topics: Extinction Adaptive radiation Convergent evolution Divergent evolution Punctuated equilibrium Changes in developmental genes 10
3 Patterns of evolution – Divergent,Convergent, and Coevolution. Darwin believed that organisms evolved gradually. (gradualism) Niles Eldredge and Stephen Jay Gould believed punctuated equilibrium is how organisms evolved, periods of rapid evolution followed by periods of stasis. BOTH REPRESENT DIVERGENT EVOLUTOIN 11
Adaptive Radiation Single species or small groups of species evolved into diverse forms living in different ways. Can lead to convergent evolution. 12
Convergent Evolution Adaptive radiation can produce unrelated organisms that look similar due to similar environments. 13
Coevolution The process by which two species evolve in Example: “This butterfly acquires a cardiac glycoside from members of the genus Asclepias. Because of their milky sap, these are commonly referred to as milkweed plants. The plants produce this toxin as a defense against herbivory, but the Monarch has the ability to sequester the toxin in fatty tissues so that it makes the butterfly unpalatable while not poisoning the butterfly.” The process by which two species evolve in response to changes in each other over time. http://ecology.botany.ufl.edu/ ecologyf02 14
Coevolution continued Also conceptually considered a biological “arms race” in some instances.
Common Misconceptions of Change Change by Desire Change by Acquired Traits Change by Use/Disuse
ADAPTATION – structural or behavioral trait that improves fitness for its habitat. 2 Examples: Camouflage or Cryptic Coloration Mimicry Not all traits are adaptations! exaptations - Features (such as feathers) that evolved by selection for one purpose (such as warmth) and were later adapted to a new purpose (such as flight).
NATURAL SELECTION Four Main Steps Variation Heritability of the variation Overproduction Reproductive Advantage due to a Competitive Advantage (Adaptation) Do changes occur in individuals or populations? Where does competition for resources fit in? Can you list 5 plant or animal adaptations? Contrast with ARTIFICIAL SELECTION (or selective breeding)
Natural Selection Process by which POPULATIONS change in response to their environment as better adapted individuals survive and leave more offspring. Generally called “survival of the fittest”. It doesn’t say biggest or strongest; it refers to the FITTEST!
Correct?
http://www.youtube.com/watch?v=xkwRTIKXaxg
This species of moth gets separated into two distinctly different forest due to the activity of humans. Draw what the moths might look like after 10 generations due to the activity of natural selection. http://www.google.com/search?rlz=1T4WZPG_enUS425US426&q=moth&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&hl=en&tab=wi&biw=683&bih=579
ISOLATING MECHANISMS -Preventing / Maintaining New Species Reproductive Isolation Prezygotic = before sex/fertilization Behavioral - Mechanical - Geographical – Temporal - Postzygotic = after sex/fertilization Sterility -
Which Isolating Mechanism?
Which Isolating Mechanism?
Which Isolating Mechanism?
Which Isolating Mechanism?
Which Isolating Mechanism?
4 Main Ways Natural Selection Changes a Population Stabilizing Selection Directional Selection Disruptive Selection Sexual Selection Page 434 – Draw the Graph and provide a summary AND a new example of each type of selection.