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  1. What is the biological species concept?
    What are limitations to this concept?
    Name 3 other species definitions in addition to the biological species definition.
    • biological species concept
    • I. Species = population or group of populationswho can interbreed in nature to produceviable, fertileof spring; but do not produce viable, fertile offspringwith other populations

    • Limitations
    • -Prezygotic barriers
    • -Postzygotic barriers

    • Other Species Definitions
    • - Morphological species (“Linnaeus type”)

    - Paleontological species

    - Ecological species
  2. Describe prezygotic and postzygotic barriers that lead to reproductive isolation.
    • Prezygotic
    • -mechanical isolation (different sizes and shapes of reproductive organs)

    -temporal isolation (mating seasons)

    -behavior isolation (mating calls, colors and shapes)

    -gametic isolation (sperm not able to attach to egg)

    • Postzygotic barriers
    • - Low zygote viability
    • - Low adult viability
    • - Hybrid infertility
  3. Describe prezygotic and postzygotic barriers that lead to reproductive isolation.
    • Prezygotic
    • -mechanical isolation (different sizes and shapes of reproductive organs)

    -temporal isolation (mating seasons)

    -behavior isolation (mating calls, colors and shapes)

    -gametic isolation (sperm not able to attach to egg)

    • Postzygotic barriers
    • - Low zygote viability
    • - Low adult viability
    • - Hybrid infertility
  4. Compare/contrast allopatric and sympatric speciation.
    What are the mechanisms for reproductive isolation with in each?
    Allopatric Speciation (other homeland)

    • - Geographic separation
    • - Gene flowinterrupted or reduced
    • - One or both populations may undergo evolutionary change

    Sympatric Speciation (together homeland)

    • - Not Geographically isolated
    • - Reproductively isolated
    • - Mechanisms of reproductive isolation

    • Mechanisms of reproductive isolation
    • - Disruptive selection: Ecological isolation due to habitat differentiation & sexual selection

    -Polyploidy: Extra sets of chromosomes, hybrid often sterile.
  5. Describe 3 outcomes of species overlap in hybrid zones over time
    1. Hybrid ZoneReinforcement: strengthening reproductive barriers

    2. Hybrid Zone Fusion: weakening reproductive barriers

    3. Hybrid Zone Stability:Continued Formation of Hybrid Individuals
  6. Where did life likely start?
    What were the raw materials necessary for it?
    What is the currently most accepted 4-step hypothesis for the origin of life?

    Explain each step. Is there any evidence to support this hypothesis?
    • - Water
    • - Methane, Ammonia, Hydrogen sulfide

    • 4-step hypothesis for the origin of life
    • 1. Synthesis of non--living organic molecules
    • 2. Joining of monomers to form polymers
    • 3. Packaging of polymers into protocells
    • 4. Origin of self--replicating molecules
  7. When did earth form?
    - Earth formed about 4..6 billion years ago
  8. How do sedimentary strata, index fossils, isotope dating and magnetism of rocks elucidate evolution in the fossil record?
    -Sedimentary strata reveal relative age of fossils

    - Absolute age of fossil—radiometric dating (isotope)

    - Magnetism of rock (reversal of poles)
  9. How is the fossil record an important source of evidence for evolutionary relationships? what are the different types of fossils?
    -allows for homologous/analogous/homoplasies relationships to be formed so that a phylogeny can be created.

    -different type of follies are found in the different strata

    • -possibly in the three eons:
    • 1. archaean
    • 2. Protozoic
    • 3.Phanerozoic
  10. What is continental drift and how did it effect evolution of life on earth?
    -continental drift is the movement of the Earth's continents relative to each other by appearing to drift across the ocean bed. SUPER continent to individual ones.

    • -Consequences:
    • 1.continent's climate can change as it moves north or south
    • 2. separation of land masses can lead to allopatric speciation
    • 3. formation of Pangea about 250 mya caused a deepening of the ocean basins, reduction in shallow water habitat and colder and drier climate inland
    • 5. evidence: distribution of fossils and living groups reflect the historic movement of continents/plate tectonics
  11. How did mass extinctions provide opportunities for adaptive radiation? Name 2 major
    mass extinctions, including the major organisms that went extinct and the likely cause(s)?
    • -Mass extinctions provide:
    • 1. fossil record chronicles on many occasions
    • 2. occur during times of rapid and disruptive environmental change
    • 3. provide opportunity for adaptive radiation

    • -Two major extinctions occurred in the :
    • 1. Permian
    • a. volcanic eruptions on many occasions
    • b.~250 mya (took less than 5mya)
    • c. 96% of all multinuclear species extinct (especially marine animals)
    • d. 8 of 27 orders extinct

    • 2. Cretaceous
    • a. impact of a large meteor
    • b. ~65 mya
    • c. many marine and terrestrial organism lost (dinosaurs)
  12. What type of organisms dominated the PreCambrian (544-3500 mya)?
    • -PreCambrian (3500-544 mya)
    • 1. life found in oceans only
    • 2. prokaryotes dominated
    • 3. Photosynthesis evolves
  13. What were the 1st photosynthesizers? How did they alter the atmosphere and open up the possibility for new organisms?
    • 1. cyanobacteria is first to photosynthesize.
    • 2. self-produce organic material leads to more food available.
    • 3. increased oxygen (i. - ii.)
    • i. symbiosis of prokaryotes leads to eukaryotic cells (endosymbiotic theory 2000mya)
    • ii. creation of ozone layer (protect from UV)
  14. Describe the Cambrian Explosion
    ~540 mya

    appearance of most of the major phyla of animals

    1st evidences of predator-prey interactions
  15. When did organisms move on to land? Which organisms arrived first? What were the
    adaptations in plants that allowed them to be successful in the terrestrial environment?
    What were the 1st animals to move onto land and what feature did they have that helped
    them to do this?
    -moved onto land about 460mya

    1st by fungi and plants

    Marine algae -> freshwater algae -> shallow water algae -> land plants (mosses, liverworts)

    • plants adaptions for living on land:
    • a. cuticle to retain water
    • b. embryos protected by parent
    • c. vascular system (conduct water/nutrients)
    • d. seeds
    • e. flowers

    • animals to land about 440mya
    • 1. 1st anthropoid move onto land
    • a. exoskeleton protects from UV and drying out
    • b. 1st centipede like
    • c. then wingless insects
    • d. then winged insects (~320 mya) similar to dragonflies

    • 2. vertebrates move onto land (~350mya)
    • a. lobed-fin fish--gave rise to tetrapods
    • b. amniotic egg develops (prevents drying)--reptiles
    • c. mammals evoked with hair and mammary glands
  16. Give an example of adaptive radiation..
    Adaptive radiation: evolution of diversely adapted species from common ancestor

    • Adaptive radiations may follow:
    • a. mass extinctions
    • b. evolution of novel characteristics
    • c. colonization of new regions

    An example is the Caribbean aniline lizards*

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review 2
2013-10-03 15:55:52
ccsf biology

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