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8/31/09
SI A ECL 365
1. Name 4 characteristics of a chordate
a. Dorsal hollow nerve cord, notochord, pharyngeal slits, muscular post-anal tail.
2.
3 subphylums of chordata?
a. Subphylum Urochordata, Cephalochordata, Craniata
3. What are some of the main characteristics of vertebrates (Craniata), when compared to the other two
phyla?
a. Cephalization – pronounced
b. Vertebral Column
4. How did vertebrates originate, according to theory?
a. Vertebrates arose from cephalochordates or larval form of urochordates
5.
What is Paedomorphosis?
a. retention of larval characteristics into adulthood
6. Evolutionary features of vertebrates
a. Living internal skeleton
b. Tie between pharynx and respiration
c. Good nervous system
d. Paired limbs
7.
Systematics and taxonomy?
a. Systematics - the scientific study of the kinds and diversity of organisms, and discovering their
evolutionary relationships
i. Describing, naming, and classifying organisms
ii. Includes several steps, including classifying organisms, providing names for organisms
and groups of organisms (and arranging them in some logical order)
b. Taxonomy: Providing names for the groups of organisms
8. What was Aristotelian essentialism and how does it relate to this course?
a. It dominated before Darwin (1859)
b. Species were considered eternal, immutable, and discrete
c. A few convenient morphological characters (‘essential traits’) were used to classify species
(e.g. animals with blood vs animals without blood)
d. Observed variation among individuals treated as aberrations around a type (idealized) form for
the species
9.
10. Carolus Linnaeus provided the scientific world with:
a. Systema naturae
b. Binomial nomenclature
c. hierarchical classification
11. Published Evolution by Natural Selection
a. Charles Darwin
12. Components of natural selection.
a. More individuals are born each generation than can survive & reproduce
b. There is trait variation among individuals
c. At least some of this trait variation is heritable
d. Trait differences are tied to fitness (i.e. some individuals have a better chance of surviving and
reproducing due to their particular traits)
13. Is natural selection random?
a. No – selection of most fit mutations
b. Mutations are random, not selection
14. Difference between anology and homology.
a. Related species should have similar characteristics
b. Based on homology (similarities due to shared ancestry) not analogy (similarities not from
shared ancestry: convergent evolution)
15. Allopatric speciation?
a. Geographic separation
16. What is Vicariant speciation?
a. Original population becomes separated (e.g. river formation, mountain rise, glacial advance)
17. What is founder effect?
a. Few individuals move far out of normal range and found a new population (rare event)
18. Are founder representative of original population?
a. Founders might not be representative of original population
b. Different conditions in each area and small size of new population favors divergent evolution
c. Often associated with colonizing islands
19. What is sympatric speciation?
a. Speciation sometimes occurs without geographical isolation; new species forms within the
range of parent species
20. What are the two forms of sympatric speciation and how are they different?
a. Ecological segregation
i. Species live in the same area, but segregate relative to specific habitat types
b. Genetic (e.g., chromosome changes)
i. Involves polyploidy – offspring getting one or more extra full sets of chromosomes (by
mistake in meiosis)
ii. Most offspring die; some live allowing the instantaneous formation of a new species
iii. Very common in plants and insects
iv. Rare among vertebrates, seen in a few fish, amphibians, and reptiles