BIO 358 Lecture Notes - Lecture 4: Asexual Reproduction, Genetic Variation, Mendelian Inheritance
14 Jun 2018
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Topic 4: How and how fast natural selection works in sexual animals
Key Terms:
1. Chromosome:
2. Genetic variation:
3. Cryptic genetic variation:
4. Mutation:
5. Allele: Refers to different versions of the same piece of genetic design information produced by mutation
(Chapter 2). For example, two different versions of a 3000 DNA base long eye color gene might be identical in
all but one position, say position 1357. At this single position one version might have a C base and the other a
G base in the DNA molecule. One version might produce green eyes and the other blue eyes. Each of these
two forms would be called a different allele of this gene.
6. Natural selection/Darwinian selection:
7. Sexual reproduction:
8. Asexual reproduction:
9. Gamete:
10. Haploid:
11. Diploid:
12. Independent assortment:
13. Crossing over (recombination):
14. Vehicle:
15. Design information = genetic design information:
16. Germline (design information) and Soma (vehicle):
17. Genotype and Phenotype:
KEY CONCEPT QUESTION: To understand what we see when we examine the evolutionary history of any
animal, including humans, we need to grasp the inherent rates of evolution by natural selection. By examining
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specific cases of well know evolutionary processes, in lecture we arrived at a clear answer to this
question. Which of the following statements most accurately and completely describes the rate(s)
of evolution by natural selection?
a. Selection is always strong, but the very limited amount of variation in populations means that evolutionary
change is always slow.
b. When selection is strong, large amounts of variation in sexual populations can allow evolutionary change to
be very rapid.
c. Because natural selection is a blind, purposeless process, selection is always weak and evolutionary change
is always slow.
d. Because changing the anatomy or behavior of an organism is extraordinarily difficult, evolutionary change is
always slow.
Notes:
1) How and how fast natural selection works in sexual animals
a) View from the gene as the unit of interest
b) Understand natural selection for what it really is and what it can produce
c) Common misconceptions
i) The preset ehiles i tie are a oerall iproeet fro past ties i history
(1) Those who became before us are less ethically better
(2) NOT necessarily true
ii) Evolution is always slow
(1) NOT necessarily true
iii) All about the survival of the species or its about benefitting the group
(1) Natural selection: gene is the only unit of interest
iv) Huas hae ypassed atural selection or risen above it
(1) No b/c we exist bc of natural selection and we are simply part OF it
(2) We are a strong selective force within it
d) Natural selection:
i) “iply a proess ith o oerall etter, orse, good, ad ethis—real or implied.
ii) No long ter pla or purpose toards a future perfet orgais
iii) SIMPLY a process resulting from the 2nd law, exponential growth, limits of a Malthusian world and
inevitable head-to-head in the moment competition between variation in genetics > that build
behaviors/resulting in differences in strategies
iv) Depending on the environment (including the social environment), a strategy that is adaptive in
oe eiroet a e a irth defet i a differet eiroet
v) Better today, here ad o ad e seletio or, can easily become worse tomorrow, there and
then, and be selected against
vi) Depending on strength of selection, natural selection can be very fast because of hidden or cryptic
variation and historicity.
e) Simplified reductionist pyramid
i) Genetic design information→ animals (individuals)→ animal societies→ human societies
f) How does evolutionary history effect animal evolution?
i) Evolutionary processes are historical processes
g) How do sexual animals evolve?
i) Phenomenon of relatedness
h) Evolution of design information shapes both bodies and minds (behaviors)
i) Human behavior is influenced by cultural influences
ii) But non-human behavior is almost completely controlled by genetic information
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Document Summary
Topic 4: how and how fast natural selection works in sexual animals. Key terms: chromosome, genetic variation, cryptic genetic variation, mutation, allele: refers to different versions of the same piece of genetic design information produced by mutation (chapter 2). For example, two different versions of a 3000 dna base long eye color gene might be identical in all but one position, say position 1357. At this single position one version might have a c base and the other a. One version might produce green eyes and the other blue eyes. Key concept question: to understand what we see when we examine the evolutionary history of any animal, including humans, we need to grasp the inherent rates of evolution by natural selection. By examining specific cases of well know evolutionary processes, in lecture we arrived at a clear answer to this question.
