Comparing Different Species Concepts

Morphological species concept says that a species is a group of organisms with…

shared traits based on morphology and external features

(+) What type of organisms can it be applied to?

asexual and sexual

(+) What doesn't it require any information on?

the extent of gene flow

(+) What type of species can it be applied to?

extinct and fossilized

(+) What type of concept is it?

the easiest and fastest to apply in the field

(-) What does the MSC rely on?

subjective criteria (may result in disagreement)

(-) How may different individuals in a species appear?

very different (male and female)

Biological species concept says that a species is a group of organisms that can…

successfully interbreed and produce fertile offspring

What does the BSC define?

why individuals of the same species are alike

(+) What does it explain the importance of?

reproduction

(+) What does it have a vital role in?

taxonomy

(-) What organisms does it not apply to?

1. that reproduce asexually

2. that are extinct

(-) What does it overemphasise and downplays?

gene flow and the role of natural selection

Ecological species concept says that a species is a group of organisms that is

adapted to a particular set of resources and its abiotic and biotic factors

What does ESC rely on?

detailed information on relationships between species and the environment

(+) What can it accomodate?

asexual and sexual species

(+) What does it emphasise the role of?

disruptive natural selection

(-) What is difficult to identify?

niches (a particular set of resources)

Why are they difficult to identify?

a niche involves the interaction between the organisms and its ab/biotic factors

Evolutionary species concept says that a species is a group of

populations that come from a common ancestor and stay distinct from other groups

What do these species have?

its own evolutionary path and adapts to different pressures

What does it focus on between groups?

genetic differences and evolutionary link

(+) What can you see?

the interrelationship between species over time

(-) What does it rely on?

fossils as not a lot of data is available