Lesson 2: Species & Speciation Flashcards
4 postulates of morphological species concept
- Species consist of similar individuals sharing the same essence;
- Each species is separated from all others by a sharp difference;
- Each species is completely constant through time; and
- There are strict limits to the possible variation w/in any one species
Which of the postulate isn’t accepted today?
Each species is completely constant through time
natural group of organisms
species
Which concept is not applicable in case of cryptic species?
Morphological Species Concept
Nature produces individuals and nothing more
Nominalistic Species Concept
Also known as morphological species concept
typological species concept
Who’s idea is the nominalistic species concept
william ockham
What’s the main point of ockham’s concept?
species are mental concepts & nothing more
It was popular in 18th century in France and still used by some botanist
nominalistic species concept
Species are the largest and most inclusive reproductive community of sexual and cross-fertilizing individuals that share a common gene pool
Biological species concept
Types of species concepts
Typological / morphological species concept nominalistic species concept biological species concept evolutionary species concept phylogenetic species concept
Who formulated first the biological species concept?
Karl Jordan 1905
Who supported Jordan’s idea in 1937?
Dobzhansky
Who supported it n 1940?
Ernest Mayr
BSC was accepted in the after of the ______ in 1859
origin of species
2 points of the concept about organism
– Organisms may appear to be alike and be different species.
– Organisms may look different yet be the same species
The 3 properties of a species by Mayr
Reproductive Community
Ecological Unit
Genetic Unit
Intercommunicating gene pool; merely a temporary vessel holding a small portion of the contents of gene pool.
Genetic unit
individuals of species recognize each other as potential mates
reproductive community
cooperatively form a unit; interact w/ other species as unit
ecological unit
3 problems w/ BSC
Asexual groups
Reproductive isolation is often incomplete
Not applicable to extinct species
why is asexual groups a problem w/ BSC?
interbreeding isn’t possible
Why does reproductive isolation is often incomplete?
hybridization
Why is it not applicable to extinct species?
fossil specimens have limited characters to look on