Chapter 22: Descent with Modification: even Answers

2) the fossil record.

4) Earth is 6,000 years old, and populations are unchanging.

6) Variations in the development of the structures occur as the embryos grow.

8) Charles Lyell

10) Alfred Wallace

12) more recently they shared a common ancestor.

14) individuals must adapt to their environment.

16) island forms and mainland forms descended from common ancestors.

18) by identifying the bones as being homologous by proposing that humans, bats, and dolphins share a common ancestor

20) baleen whales are descendants of toothed whales.

22) DNA or RNA analysis

24) The amount of available food may have increased. The number of predators may have decreased. The squirrels of subsequent generations should show greater levels of variation than previous generations because squirrels that would not have survived in the past will now survive.

26) Of the following anatomical structures, which is homologous to the wing of a bat?

arm of a human

DNA Technology and Genomics answers

2) a plasmid used to transfer DNA into a living cell.

4) by adding methyl groups to adenines and cytosines

6) III, II, IV, V, I

8) recombinant plasmids of bacteria. recombinant viral DNA.

10) A genomic library contains both noncoding sequences and coding sequences, whereas a cDNA library contains only coding sequences. A genomic library is identical regardless of the cell type used to make it, whereas the content of a cDNA library depends on the cell type used in its construction. A genomic library can be made using a restriction enzyme and DNA ligase only, whereas a cDNA library requires both of these as well as reverse transcriptase and DNA polymerase.

12) centromere telomeres origin of replication

14) 2, 1, 4

d 16)

e 18)

20) gel electrophoresis

22) The fragments must be separated by electrophoresis. The fragments must be treated with heat or chemicals to separate the strands of the double helix. The probe must be hybridized with the fragment

24) restriction enzyme recognition sites between the alleles.

26) RNA transcripts of human genes are more likely to undergo alternative splicing. Post-translational processing adds diversity to the resulting polypeptides. Polypeptide domains are combined in a variety of ways. Gene expression patterns in humans are often more complex than those in other organisms.

28) the number of proteins in humans probably far exceeds the number of genes. a cell's proteins differ with cell type. proteins are extremely varied in structure and chemical properties.

30) cleaning up toxic waste. manufacturing human growth hormone.

32) be cut by the same restriction enzyme.

34) a somatic plant cell can often give rise to a complete plant.

36) introduction of genetically engineered genes into human gametes