The Origin of Species

1. Chapter 24 The Origin of Species Questions prepared by Jung Choi Georgia Institute of Technology Michael Dini Texas Tech University

2. Biological Species are members of different populations cannot mate and produce viable, fertile offspring are geographically isolated live in different habitats look different 1. Two animals are considered members of different species if they _____.

3. Biological Species See whether the two populations are morphologically different from each other: coloring, bone structure, and so on. Determine whether captured individuals from the two different populations will mate and produce offspring in a laboratory fish tank. Determine whether individuals from one population will interbreed with individuals from the other population when introduced into each other’s native habitats. 2. Cynotilapia afra, introduced at West Thumbi Island in Lake Malawi in the 1960s, has split into two genetically distinct populations, located at the north and south ends of the island. How can scientists determine whether these populations are now different species, according to the biological species concept?

4. Phylogenetic Species a clone of genetically identical organisms a population that is physically able to mate even if there are no offspring or the offspring are infertile a population that interbreeds and produces fertile offspring a set of organisms with a unique genetic history a population with a distinct fossil record 3. According to the phylogenetic species concept, what is a species?

5. Mechanism of Reproductive Isolation polyploidy female mating preferences differing habitat preferences temporal isolation mechanical isolation 4. If the two populations of C. afra at West Thumbi Island have different striping patterns, what might be a likely mechanism contributing to speciation?

6. Species Concepts biological species concept phylogenetic species concept ecological species concept morphological species concept 5. Which species concept is least useful for classifying prokaryotes?

7. Mechanisms of Adaptation changing the expression of genes that control the growth of different jaw bones during development evolving new genes that generate new jaw bones acquiring genes by hybridizing with other species that exploit the same food source individuals exercising their jaw muscles in different ways, causing the jaws to grow accordingly 6. In vertebrate radiation, exemplified by African cichlids, modification of jaws occurs during adaptation to different food sources. Such rapid modifications could result from which of the following?

8. Allopatric Speciation having a large number of individuals being highly mobile existing on the edge of the home range having a relatively homogeneous home range having a relatively homogeneous gene pool 7. Which population characteristic would make the population more likely to undergo allopatric speciation?

9. Speciation and Physical Environment areas that have a large range of altitudes, such as mountains and deep valleys areas such as large plains that facilitate migration of animals extreme physical environments that are marginal for supporting life areas that are already species-rich areas that have undergone recent environmental disturbance or change 8. In what type of environment is a scientist most likely to find examples of ongoing speciation?

10. Reproductive Isolation Mechanisms behavioral isolation or mechanical isolation gametic isolation or temporal isolation habitat isolation 9. Sea urchins are broadcast spawners: They release their gametes into the water, without courtship. Which of these reproductive isolation mechanisms might operate for sea urchin species?

11. Human Brain Evolution One or a few novel genes organized new brain structures. The timing of the expression of brain development genes altered. Brain development genes acquired mutations that made them more active in promoting brain growth. Genes that had other functions acquired new functions in brain development (exaptation). 10. A comparison of the human and chimpanzee genomes shows that they are 99% identical, with very few differences in protein coding genes. What mechanisms may be responsible for evolution of the human brain?