BIOL 215 Speciation

Question 1

Define speciation.

Answer 1

The process by which new species arise.

Question 2

Define specie.

Answer 2

It is a complex concept with various definitions. Specie is a fundamental taxonomic category to which individual specimens are assigned.

Question 3

What are the [4] different ways to define specie and why are they not able to chose one ?

Answer 3

Biological
Evolutionary
Phenetic
Phylogenetic

None of those concepts can apply both on all asexually and sexually reproducing individuals.

Question 4

Define the biological species concept (BSC).

Answer 4

The more used concept
Reproductively isolated community of individues interbreeding among themselves and are genetically isolated from other groups.
+ : defines species on the basis of criteria important to
their evolution
members define their own specie
-: Exceptions exist
Really long to test

Question 5

Define the phenetic species concept (PSC).

Answer 5

Includes individuals sharing common phenotypic characteristics (morphology, physiology, behaviour) and morphospecies → comparative nataomy and embryology
+ : really easy to apply
- : Requires arbitrary decisions
Animals sharing common characteristics may be classified as the same specie even if it’s not the case

Question 6

Define the Evolutionary species concept (ESC)

Answer 6

An ancestral-descendant sequence of
of populations evolving separately from others and
with its own evolutionary role and tendencies.

Include paleospecies
\+: applicable on living and extinct groups
-: not really operational
   end up to use morphology
   not all fossils are available

Question 7

Define the phylogenetic species concept.

Answer 7

Concept based on genetic similarities : “the smallest diagnosable cluster of individual organisms within which there is parental pattern of ancestry and descent”

Include Agamospecies

+ : operationally defining species
- : The method used for reconstructing those
clusters will have big effect on outcome
History of different genes can give different
results

Question 8

What are the two types of process of speciation and what are their main common characteristic?

Answer 8

Allosympatric
Sympatric

Most of the time, it is followed by an ecological isolation.

Question 9

In populations, why is species stay relatively stable ?

Answer 9

Gene flow between populations may slow or even inhibit local specializations and so promote continuance and stability of the species.

Question 10

What are the three types of allopatric speciation ? What do they all have in common ?

Answer 10

Allopatric speciation
Peripatric speciation
Parapatric speciation

Are all caused by geographic isolation

Question 11

Define allopatric speciation.

Answer 11

Population separated in 2 by a natural physical obstacle or one part of the population extinct.

Question 12

Define peripatric speciation.

Answer 12

Population separated by the budding off of an individual to form a new colony.

Question 13

Define parapatric speciation.

Answer 13

When the environmental conditions differ in the same population, one part will evolve to adapt to the different conditions.

Question 14

What are the three steps of allopatric speciation ?

Answer 14

1. geographical separation
2. Local adaptation
3. Reproductive isolation

Question 15

Define sympatric speciation.

Answer 15

A modification in the genome occur without any geographic barrrier which lead to a new specie that can not reproduce with the other specie. It is very controversial model and the only phenomenon accepted is poploidy in plants.

Question 16

What is ecological isolation ?

Answer 16

It is a process coming after allopatric and sympatric speciation that permits to isolate the species and generate reproductive isolation ex: selection against hybrids, difference of behaviour, habitat preference