B17 Evolution Flashcards
Theory of Evolution
Gradual change in inherited characteristics of a population over time
Occurs by process of natural selection
Can result in new species
Process of natural selection
Individuals with most suited characteristics to the environment are more likely to survive and breed
Darwin’s work
All species had a common ancestor from 3 billion years ago
Natural selection
Why was Darwin’s work only gradually accepted?
He challenges the idea that God made all of nature
Mechanisms of inheritance and variation were not known at the time
Insufficient evidence at the time the theory was made
What evidence do we have for evolution?
Fossil record
Evolution of antibiotic resistance in bacteria
Who published the theory of speciation?
Alfred Wallace
What is the theory of speciation?
Gradual formation of new species as a result of evolution
Describe the process of speciation
- Species is isolated ( e.g by a river )
- Natural selection occurs
- Populations have an increasing number of genetic mutations
- Eventually they’re 2 new species and cannot breed
Factors that increase rates of extinction
New predators
New diseases
Increased competition
Catastrophic events
Changes to environment
Benefits of fossil record
Can tell scientists how a species has changed over time
Allow us to understand Earth’s history
Can be used to track movement of species across the world
Problems with the fossil record
Many early organism’s were soft bodies so they could not form fossils
There are gaps in the fossil record
Who created the Classification system?
Carl Linneaus
Classification system
Kingdom, Phylum, Class, Order, Family, Genus, and Species
Who created the 3 domain system?
Carl Woese
What is the 3 domain system?
All living organisms are divided in to :
- Archaea
- Bacteria
- Eukaryota
