Class notes Biology species Biology 11, ISBN: 9780070915800

Species
Chapter 1
Species - Group of organisms that can interbreed & produce fertile offspring

Species Concepts
= Definition of species

Morphological Species Concepts
= Examines Morphology
- Structure of organisms
- Ex: Body shape, size etc.
- Compares measurements + descriptions of similar organisms
- Species change over time (variation)
- Scientists determine whether similar organisms are different species
Pros Cons

- Simple to use - How much difference is too much variation??
- Most populations have non-identical individuals




Biological Species Concepts
= Ability to interbreed in nature + produce fertile offsprings
- If so, they are the same species


Pros Cons

- Widely used - If 2 populations are physically separated, no chance to

, interbreed in nature
- Dunno if offspring would be viable or not
- Useless against organisms that can produce aesexually, fossil
species




Phylogenetic Species Concepts
= Examines Phylogeny
- Evolutionary history of species
= Species is defined as a group of organisms that’s different from other groups
- Gotta have a pattern of relationship among organisms
- Ex: If a prehistoric species branches into 2 species, there’s now 2 different
phylogenetic species
= DNA analysis provides more evidence to how species are related
Pros Cons

- Applicable to extinct species - Evolutionary history not know for all species