Lecture 24: what is a species and how do they arise?

Question 1

3 Major Species Concepts

Answer 1

Typological
Biological
Phylogenetic

Question 2

Typological species concept

Answer 2

• the idea of a perfect type
  includes:
  • identification book (sometimes two animals within the same species are very different) ex. dogs are all VERY different based on their skull types

Question 3

Biological species concept

Answer 3

MOST POPULAR
- the evolution of things that prevent you from breeding with another group (most species interbreed with at least another species)
• Problems:
- difficult for allopatric populations (some species would never come into contact)
- not particularly used for fossils

Question 4

The process of Speciation

Answer 4

• starts with barrier
• two populations diverge genetically, but are still reproductively compatible
• finally, reproduction incompatibility is established

Question 5

Phylogenetic Species Concept

Answer 5

• a species is a discrete lineage, ancestor to descendent shares a distinct evolutionary history
• always based on genetic data and is just a function of time with separation
  • Problems:
• cannot be used for fossils
• only reflects time, not reproductive barriers

Question 6

Polypoidy

Answer 6

having duplications of genomes

- hybrids wont do well when you interbreed

Question 7

Hybridization

Answer 7

• hybrids cant mate with themselves

Question 8

Ecological speciation

Answer 8

• disruptive/divergent selection drives adaptive divergence (pushes populations apart)
• reproductive isolation evolves a consequence (due to divergent selection, you no longer interbreed)

Question 9

Ecological speciation predicts

Answer 9

DARWINS FINCHES

1. two morphs feed on different food (ecological contrast)
2. intermediate birds survive at lower rates (disruptive selection
3. each match should prefer to mate with its own morph (mating isolation)
   - same sized beaks
4. the two morphs should be reproductively isolated

Question 10

mating costs for water striders

Answer 10

• males would go on top of females
• females would kick them off
• males adapted structures to grab onto females
• females adapted structures to kick off males
  SEXUAL CONFLICT DRIVES DIVERGENCE IN MATING TRAITS IN SPECIES

Question 11

Wolbancha

Answer 11

• 15-20% of insects carry Wolbancha
two unaffected insects——> produce offspring
two affected insects——> produce offspring
male unaffected, female affected—-> produce offspring
male affected, female unaffected—-> no offspring
SOMEHOW IT MODIFIES THE SPERM IN MALES