Chapter 24

The Origin of Species(cont.)

Questions to ponder

Natural hybridization is common and hybrids are not uniformly unfit, they are genotypic classes that are less, equally or more fit than their parental taxa.Some scientists think that hybridization could generate biological diversity. How?

Hybridization is common when populations invade new environments. Why?

Caulerpa taxifolia hybrid

Alexande Meinesz

1- Do you have practice or old exam for study use in order to grasp an idea of how your tests will be formatted?

2-If there are questions such as the “chick discussion” on the test, is it safe to say that you do agree with whichever statement, but you don’t know if there are any factors that may cancel it?

3- Is a hybrid always a new species or can they breed back to their parent species?

4- Are mating habits in species inherited or are they a consequence of the environment?

5- How much genetic difference does there need to be to consider two populations different species?

SOME questions from January 18th

Modes of Speciation(based on how gene flow among populations is initially interrupted)

1- How would you characterize each mode of speciation?

Fig. 24.6

Fig. 24.7

Allopatric Speciation

Fig. 24.11

Adaptive Radiation

Isolation and occasional dispersal.

Evolution of many diversely adapted species from a common ancestor.

Fig. 24.14

Sympatric Speciation

menua

Resident

Transient

P. Stap

Orcinus orca

R. Baird

unknown

Fig. 24.16Sympatric Speciation

Tempo of Speciation3- How do you characterize each model for the tempo of speciation?

Fig. 24.17

4- What is the difference between microevolution and macroevolution?5- How could complex structures such as eyes evolve?

Mechanisms of macroevolution

6- Allometric growth determines the proportion of the body due to the different growth rates of different body parts. How can it act as mechanism of macroevolution?

Mechanisms of macroevolution

Fig. 24.19

7- Is evolution goal oriented. Why?

Fig. 24.24