NATURAL SELECTION
● Evolution by natural selection
○ Formed by Wallace and Darwin
○ Individuals with favorable inherited traits are more likely to survive & reproduce
● Theory explains:
○ Unity of life
○ Diversity of lids
○ Match between organism and their environment
● Darwin and Wallace evolution by natural selection
○ Proposed species change through time
○ No linear, progressive pattern
○ Based on variation within population
○ Individuals with traits produce more offspring than those without
○ Darwin's view: history of life = like a tree with branches
● Evolution as descent with modification:
○ Change over time produced modern, modified species
4 postulates
1. Variation exists among individuals that make up populations
2. Some trait differences are heritable (DNA)
3. Survival and reproduction success is highly variable
4. Subset of individuals that survive best will produce most offspring
a. Traits that will give them an advantage
● Evolution by natural selection occurs when:
○ Heritable variation leads to differential reproductive success
● How natural selection differs from previous views
○ Lamarckian evolution is progressive
○ Producing larger more complex “better” species over time
○ Organisms evolve by moving up
● Lamarck and idea of evolution through time
○ Suggested species evolve through use and disuse of body parts
○ Inheritance of acquired characters
○ Individuals develop phenotype changes in response to environmental challenges
○ Phenotypic changes are passed to offspring
○ Ex: giraffes develop long necks from stretching to reach food and produce offspring w
long necks (not true)
● Lamarck → inheritance of acquired characters (individuals)
● Darwin → descent with modification (populations)
Species: Distinct, identifiable group of populations whose members can be interbreed
● Adaptation
○ Heritable trait that increases fitness of individuals in particular environment
● Biological fitness
○ Ability of individuals to produce surviving, fertile offspring
● Evolution by natural selection
○ Formed by Wallace and Darwin
○ Individuals with favorable inherited traits are more likely to survive & reproduce
● Theory explains:
○ Unity of life
○ Diversity of lids
○ Match between organism and their environment
● Darwin and Wallace evolution by natural selection
○ Proposed species change through time
○ No linear, progressive pattern
○ Based on variation within population
○ Individuals with traits produce more offspring than those without
○ Darwin's view: history of life = like a tree with branches
● Evolution as descent with modification:
○ Change over time produced modern, modified species
4 postulates
1. Variation exists among individuals that make up populations
2. Some trait differences are heritable (DNA)
3. Survival and reproduction success is highly variable
4. Subset of individuals that survive best will produce most offspring
a. Traits that will give them an advantage
● Evolution by natural selection occurs when:
○ Heritable variation leads to differential reproductive success
● How natural selection differs from previous views
○ Lamarckian evolution is progressive
○ Producing larger more complex “better” species over time
○ Organisms evolve by moving up
● Lamarck and idea of evolution through time
○ Suggested species evolve through use and disuse of body parts
○ Inheritance of acquired characters
○ Individuals develop phenotype changes in response to environmental challenges
○ Phenotypic changes are passed to offspring
○ Ex: giraffes develop long necks from stretching to reach food and produce offspring w
long necks (not true)
● Lamarck → inheritance of acquired characters (individuals)
● Darwin → descent with modification (populations)
Species: Distinct, identifiable group of populations whose members can be interbreed
● Adaptation
○ Heritable trait that increases fitness of individuals in particular environment
● Biological fitness
○ Ability of individuals to produce surviving, fertile offspring
