Review of molecular biology

Transcription

1 Review of molecular biology DNA is into RNA, which is into protein. What mrna sequence would be transcribed from the DNA template CTA? What sequence of trna would be attracted by the above mrna sequence? How many amino acids would be translated from three mrna codons?

2 Review of biotechnology Why is detergent used in DNA extraction? Gel electrophoresis separates DNA fragments based on? What is PCR used for? How does molecular cloning take advantage of unique characteristics of bacteria? What do restriction enzymes do? How has biotechnology advanced vaccines, antibiotics, and hormone treatments? Why do the transgenic mice from the example fluoresce? What is genomics, and what is meant by model organism? What are some pros and cons of GMOs in our society?

3 CONCEPTS OF BIOLOGY Chapter 11 EVOLUTION AND ITS PROCESSES Part 1

4 The diversity of life on Earth is the result of evolution, a continuous process that is still occurring FIGURE 11.1

5 Does evolution act on individuals or populations? Darwin vs. Lamarck Evolution vs. natural selection Is a certain trait (ex: long necks) always selected? FIGURE 11.1

6 Darwin observed that beak shape varies among finch species He hypothesized that the beak of an ancestral species had adapted over time to equip the finches to acquire different food sources FIGURE 11.2

7 (a) Charles Darwin and (b) Alfred Wallace wrote scientific papers on natural selection that were presented together before the Linnean Society in 1858 FIGURE 11.3

8 Evidence for evolution by natural selection: A drought on a Galápagos island in 1977 reduced the small seeds available, causing many small-beaked finches to die This caused an increase in finches average beak size Natural selection can only take place if there is variation among individuals (source of variation?) FIGURE 11.4

9 Flowering plants evolved from a common ancestor The (a) dense blazing star and (b) purple coneflower vary in appearance, yet both share a similar basic morphology FIGURE 11.5

10 Divergent evolution (homologous structures) vs convergent evolution (analogous structures) Homologous = same structure, different function Analogous = different structure, same function

11 Four important evolutionary forces can disrupt the equilibrium of alleles in the gene pool 1. Natural selection (can include nonrandom mating) 2. Mutation (source of new alleles) 3. Genetic drift (includes bottleneck and founder effects) 4. Gene flow (migration) Are natural populations ever in true (Hardy-Weinberg) equilibrium?

12 As the Industrial Revolution caused trees to darken from soot, darker colored moths were better camouflaged than lighter colored ones, which caused there to be more darker colored moths in the population (natural selection) Did the allele for dark coloration increase or decrease in the gene pool? FIGURE 11.6

13 Genetic drift may eliminate an allele by chance A random set of individuals produces the next generation What populations are most susceptible to genetic drift? FIGURE 11.7

14 In a population bottleneck, a chance event or catastrophe can reduce the genetic variability within a population What populations are susceptible to population bottleneck? Founder effect is similar FIGURE 11.8

15 Gene flow can occur when an individual travels from one geographic location to another and joins a different population Examples in human society? FIGURE 11.9

16 Evidence of evolution by natural selection (fossils) Horse species shown are only four from a diverse lineage with many branches, dead ends, and adaptive radiations One of the trends shown is the evolutionary tracking of a drying climate and increase in prairie vs forest habitat What physical adaptations you notice? FIGURE 11.10

17 Evidence of evolution by natural selection (anatomy & embryology) Image: McGraw-Hill

18 Anatomy: similar (homologous) structure of forelimbs indicates these organisms share a common ancestor What are vestigial structures? FIGURE 11.11

19 Convergent evolution: the white winter coat of (a) the arctic fox and (b) the ptarmigan s plumage are adaptations to their environments FIGURE 11.12

20 Evidence of evolution: biogeography This family of plants evolved before supercontinent broke up Today, members of this plant family are found throughout the southern hemisphere (red) FIGURE 11.13

21 Evidence of evolution: molecular biology Universality of DNA as genetic material, near-universality of genetic code and machinery of DNA replication Shown: homologous gene expression Image: content/variation/hoxgenes/

22 Review of evolution (part 1) How are evolution and natural selection related? Why is it important to have variation (genetic diversity) in a population? Divergent vs convergent evolution What are the four important forces that drive evolution? Know examples of each What types of evidence exist in support of natural selection and evolution?