Ch 4: Mendel and Modern evolutionary theory. Week 4 (Ch 3/4)

Transcription

1 Ch 4: Mendel and Modern evolutionary theory Week 4 (Ch 3/4) 1

2 -Anthro club -Social sciences night -Quiz Thursday, October 4th ---- Mendel's principles of inheritance Synthetic theory of evolution Homework pass back 2

3 Synthetic theory of evolution Synthetic theory of evolution -modern synthesis of Darwin's theory and genetics now: Evolution defined: change in allele frequencies of a population from one generation to the next. Gene pool: the genetic material (alleles) making up a population of organisms 3

4 Synthetic theory of evolution Two-stages of evolution involve variation and natural selection Stage 1: Factors produce and redistribute variation Stage 2: Natural selection acts on variation Microevolution: changes from generation to generation Macroevolution: speciation, changes over time evident in the fossil record 4

5 Factors producing and redistributing variation 1. Mutations: any change in alleles -produces new alleles (only source of new genetic material) -only passed on if occurs in gametes 2. Recombination: chromosome pairs exchange DNA during meiosis shuffling variation for natural selection to act on 5

6 Factors producing and redistributing variation 3. Genetic drift: changes in allele frequencies due to chance Founder effect: small subpopulation starts new popn Bottleneck: population shrinks and recovers E.g., Pingelap islanders today are mostly colorblind 6

7 Factors producing and redistributing variation 4. Gene flow: (migration) exchange of genes between populations E.g., significant gene flow between human populations explains the low occurrence of hominin speciation in the past million years 7

8 Variation and natural selection Natural selection -directional change relative to environment -acts on variation 8

9 On the essay Again, here's the best structure/outline you should follow: Introduction paragraph Give thesis (statement). Outline how you'll support your thesis statement Body paragraphs Paragraph 1 Paragraph 2 Paragraph 3 Conclusion Restate thesis. Briefly summarize the content of the essay body supporting it. 9

10 On the essay Also be aware of the following issues -Don't just fill the essay with extended quotes or rely on quotes from the book to define/describe stuff. -If you use a term/concept that's in bold in the text then you should briefly define/explain what the concept is. 10

11 On the essay Example of the first in text citation of a single resource: Okay: Biocultural evolution (the mutual, dynamic evolution of human biology and culture) "resulted in many anatomical, biological, and behavioral changes during the course of human evolution" and still influences the patterns we see in modern human populations (Jurmain et al. 2016; 10). Also okay: Biocultural evolution (the mutual, dynamic evolution of human biology and culture) "resulted in many anatomical, biological, and behavioral changes during the course of human evolution (Jurmain et al. 2016; 10)." and still influences the patterns we see in modern human populations. 11

12 On the essay ALL citations of the same text should look like this: Okay: Physical anthropology is a scientific field because it uses a modern evolutionary framework. Another reason is its reliance on "the principles of the scientific method (19)" which compels scientists to generate hypotheses to explain their observations and then rigorously test and see if our tentative explanations are disconfirmed, need to be revised, or become a theory, i.e., a confirmed explanation of the facts. Also okay: Physical anthropology is a scientific field because it uses a modern evolutionary framework. Another reason is its reliance on "the principles of the scientific method" which compels scientists to generate hypotheses to explain their observations and then rigorously test and see if our tentative explanations are disconfirmed, need to be revised, or become a theory, i.e., a confirmed explanation of the facts (19). 12

13 Macroevolution:larger scale change over geologic time Classification: classify organisms to understand evolutionary relationships Kingdom: Animalia Phyla: 20 major phyla including Phylum Chordata Class: Mammalia is a class of chordates Order: Primate Family: Hominidae Genus: Homo Species: sapiens 13