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Charles Darwin
- 1809-1882 British
- 1831- Done w theology school
- Naturalist on HMS Beagle 1831-1836 (5 years)
- Galapagos islands (off pacific s america) 6 weeks
- -Saw: toroises, mocking birds, finches, cacti, etc...
- Came home- thought/writing/reading/communication
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Thomas malthus
- 1798 Essay
- Charles lyell 1830 geology (earth is old)
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1842
- Essay of 1842
- Not published
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1858
- Got a letter from naturalist Alfred Russell Wallace
- July 1st 1858 - joint papers given by wallace and by darwin
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1859
- Published "origin of species"
- Ideas- world is not static, it is changing
- Change could be spoken as "evolving"
- Evolution is "Gradual"
- Natural selection is a process / results in evolution
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Phenotype / Genotype:
Physical characteristics
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Population:
Group of organism, interbreeding, in 1 area, in 1 species
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Gene pool
at the genes in a population
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Environment:
- biotic factors - Living
- abiotic factors - non living
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Natural Selection -
- Differential perpetuation (survivial/reprodcution) of genotypes
- (some genotypes do better than others)
- 1. organisms can reproduce sexually
- 2. there is inheritable variation
- 3. testing of organisms by environment
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EXAMPLE OF NATURAL SELECTION:
- Gophers: digging abilities
- F: faster
- f: slow
- FF Ff ff
- Foxes eat ff --> FF Ff
- Example of natural selection - some genotypes have done better than others.
- Allele freq: Before: F 3/6 f 3/6
- After: F 3/4 f 1/4
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Change in allele frequencies:
- "microevolution"
- Natural Selection is a process and results in microevolution
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Types of NS: stabilizing NS
- 1. Stabilizing N.S.
- Example: human birth weight
- Those on ends of curve are at a disadvantage
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Directional NS
- individuals at one end of the curve are at an advantage at other end they are at a disadvantage.
- Ex: squirrels w longer fur survive through winter
- Ex: increased resistance to antibiotics in bacteria
- Ex: Plants around mine tailings
- Ex: moth coloration: Melanistic moths *industrial melanism)
- Pre 1850- moths were light, mostly
- Post 1850- many moths are dark
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Adaptation:
- Any function or structure that produces better adjustment of organism to environment.
- Natural selection (process)---> adaptation
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Microevolution:
- Change in allele frequencies through time
- (NS) process ----> microevolution
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CoEvolution:
2 or more species interacting, and they are selective force on other. (deer and wolves)
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Variabiltiy 0
- IT EXISTS-
- 1. origin - mutation
- 2. How is it observed / quantified?
- a) morphological variation (ex flower color)
- b) enzyme variabilty -
- allozymes- alternate forms of an enzyme
- -coded for by same locus
- -gel electrophoresis may tell them apart
- H: heterozygosity - % loci heterozygous in an individual (humans 7%)
- P: polymorphism - % loci polymorphic in an population (humans 38%)
- c) variation in DNA - more vairabilty in dna than in enzymes.
- aa - diff codons --- variability
- d) eq of variabilty - hemoglobin molecule (sickle cell anmenia)
- Higher in africa - carrier for sickle cell - immune to malaria
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Arguments for variability:
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