9. Individual and Species Concepts

Question 1

Hybridization

Answer 1

Different species interbreeding

• Can create a viable offspring
• Some hybrids are more vigorous “hybrid vigor”

Question 2

Why are hybrids not common

Answer 2

• Non-overlapping ranges
• Different courtship rituals
• Generally sterile

Question 3

Plant hybrids

Answer 3

Plants readily hybridize

• Hybrids are often fertile
• Even sterile ones can asexually reproduce

Question 4

Darwin’s Species

Answer 4

Groups of morphologically similar individuals

Question 5

Biological Species Concept

Answer 5

Ernst Mayr
Defined by the ability to reproduce.
- A population whose members are able to interbreed freely under natural conditions, and are reproductively isolated from other populations

Question 6

Problems with Biological Species Concept

Answer 6

Asexual Species
Lateral gene transfer
Sexual Species with alternative reproductive methods
- Parthenogenetic
- Incipient Species
- Chronospecies

Question 7

Incipient Species

Answer 7

Two species that can interbreed when put together but are reproductively isolated

Question 8

Chrono species

Answer 8

Two or more species separated by time

- First species evolved into the other

Question 9

Species problem

Answer 9

Can’t find a theory that

• apply to asexual and sexual organisms
• Differentiate chronospecies
• Classify hybrids

Question 10

Evolutionary Species Concept

Answer 10

Proposed by a paleontologist

• Lineages that are evolutionarily indipendent in their passage through time
• Basically branches of phylogenetic tree

Question 11

Problems of Evolutionary Species Concept

Answer 11

• Defines species but doesn’t include a mechanism for recognition
• Two species from the same ancestor?

Question 12

Operational Species Concept

Answer 12

More than one theory

• One or more derived characteristics
• Smallest natural aggregation of individuals that can be defined by a current set of analytical techniques
• Smallest sample of self - perpetuating organisms that have a unique set of characters

Question 13

Problems of Operational Species Concepts

Answer 13

• Emphasis on visually identifiable characters - includes asexual and hybrids
• Does not address evolutionary relationship
• Does not cover cryptic species - Tapanuli orangutan, Atlantic coast frog

Question 14

Ecological Species Concepts

Answer 14

Defined by their niche

• If share the same niche in same environment - Same species
• Hard to prove what the niche is

Question 15

DNA Barcoding

Answer 15

Short genetic sequences compared

• CO1 gene
• Only useful when other species are already classified
• Accuracy depends on the number of known species

Question 16

Molecular Phylogeny

Answer 16

Determine evolutionary relationships by examining and comparing heredity molecular differences
- Used to build the tree for barcoding

Question 17

Limitations of “beyond biological species concept”

Answer 17

• Limitations in DNA techniques

- How different do they have to be?

Question 18

Synthesizing Species Concepts

Answer 18

Chose best definition depending on the situation

Question 19

Identifying a species for identification

Answer 19

Operational Species Concept

Question 20

Discussing how species are formed and maintained

Answer 20

Evolutionary Species Concept

Question 21

Working with sexually-reproducing and isolated populations

Answer 21

Biological Species Concept