INDENTIFYING SPECIES

Question 1

morphological species

Answer 1

focus on morphology (body shape, size, etc) to decide whether similar organisms represent different species.
Advantage: simple to use.
Disadvantage: Hard to decide how much difference is too much because all populations are made up of non-identical individuals.

Question 2

biological species

Answer 2

based on whether 2 organisms can produce viable, fertile offspring.
Advantage: widely used in science.
Disadvantage: cannot be applied in all cases: fossil records (because those species are no longer reproducing), on populations that are physically separated and have therefore never had the chance to interbreed.

Question 3

phylogenetic species

Answer 3

examine the evolutionary history of organisms – seeing patterns of relationships and seeing when they branch into 2 species over time.
Advantage: able to incorporate DNA evidence, can be applied to extinct species.
Disadvantage: evolutionary histories are not known for all species.