Evolution Flashcards
Platos beliefs
Objects are represented by ideal forms
Variation isn’t important
Aristotles beliefs
Species don’t change
Natural order doesn’t change
Jean Lamark
Linear force- evolution towards inc complexity
- driven by internal force
Lateral force- adaptation to local conditions
- have certain traits for their environment
Charles Darwin
Proposed mechanism to explain evolution, waited 30 years to release
Natural selection
Alfred Wallace
Developed same idea as Darwin but let Darwin publish
Darwin
Define
Uniformitarianism
World under slow constant change.
Lyell
Define essay on populations
Human populations grow faster than resources
Malthus
Darwins theory of natural selection: 3 points
All can reproduce at exponential rates
Populations can’t increase exponentially
Resources are limited (Malthus ideas on essay population)
What were darwins four conclusions?
- Struggle for existence within a species
2 survival depends on varying traits - Populations evolve
- All species have evolved from a common ancestral species
What is artificial selection?
Organism can be bred into different species
Biogeography
Organisms from one region are more similar than from another region
What are homologous structures?
Parts similar in structure but have entirely different functions
What. Are analogous structures?
Parts different in structure but have similar functions
Vestigial parts
Serve no function
What is molecular biology?
Relationships can be implied from chemical similarity of organisms
What is coevolution?
Organisms that rely on others show evolutionary similarities
What are the four arguments against evolution?
Lack of intermediate forms in fossil records
Dilution of favourable traits
Blind watchmaker - mutation is random
Irreducible Complexity
Stabilizing selection
Average traits are selected
Occurs when environment is stable
Directional selection
Higher OR lower traits are selected
Occurs when environment changes and organisms adapt
Disruptive selection
Higher AND lower traits selected
When resources are unevenly distributed
Frequency dependent selection
Uncommon traits are selected
Increases variation and diversity
Balances out traits making more common
Sexual selection
May have traits that decrease ability to survive but increase ability to breed
What are the two forms of sexual selection?
Females pick males
Males compete
What is random selection?
Change in genetic makeup of population by random events
Founder effects
Some individuals Ina population migrate to different area and have some different traits than population they left
Bottleneck effects
All but a few are eliminated in a population. Survivors don’t have same traits as original population
Genetic drift
Non adaptive change in population over time
Define typological/ morphological species
Group of individuals sharing similar characteristics
Ex. Tigers to lions
Define Biological species
Organisms that can produce fertile offspring
What are the issues with biological species theory?
Doesn’t work for asexual organisms
Difficult to test
Same species can evolve into two and still produce offspring
What are three barriers that prevent different species from interbreeding?
Gamete isolation
Behavioural barriers
Mechanical isolation
What is a behavioural barrier?
Species:
Occupy different habitats
Breed at different times
Different mating behaviours
What is mechanical isolation?
Structural differences prevents mating
Example: certain dogs
What is gamete isolation?
Gametes are prevented from uniting due to incompatible cell surfaces
What are two processes of species formation and explain
- Formation of species through geographic isolation he population is split and eventually isolation from eachother leads to differences
- Formation of species without geo isolation
Polyploids
What is the formation of polyploids?
Organisms with two or more complete sets of chromosomes
Can’t cross with parents
Can lead to issues in animals
But works out nicely for plants
