B2.8 Speciation Flashcards
State speciation
Speciation - new species develop
Define a fossil
The preserved remains of organisms
Define extinction
The permanent loss of all members of a species
Define endangered
When the species is near extinction
What are the reasons for extinction
Introduction of NEW diseases Introduction of NEW competitors Introduction of NEW predators Lack of nutrients Environmental change
How are fossils made?
Ice
Amber
Sedimentation
pH conditions
Define species
A group of similar organisms that can interbreed
What is speciation?
Separation Genetic variation Natural selection Alleles passed on Species can no longer interbreed
What are the limitations of the fossil record?
Early organisms were soft-bodied
Fossils can get damaged e.g. by geological activity
There are often gaps in fossil records
How can fossils give evidence for evolution?
Fossils show change over time
Why are scientists not sure of what the skin of extinct organisms were like?
The skin decays
What can we learn by studying fossils?
Evolution
The age of the fossil
Habitats
When answering a 4 mark question for speciation what are your four steps?
- State how species can be geographically isolated.
- Describe what is meant by variation + explain what it’s caused by.
- Describe what natural selection is.
- Describe what is meant by speciation.
Define natural selection
Natural selection - when a organism adapts to an environment better than another organism
Define genetic variation
A difference in a gene.
