Download Slides Lec08 - the ant life

3/3/2014
Spring 2014: Mondays 10:15am – 12:05pm (Fox Hall, Room 204)
Instructor: D. Magdalena Sorger
Website: theantlife.com/teaching/bio295-islands-evolution
LECTURE 08
Today:
Quiz follow‐up
Follow‐up on minute papers
Evolutionary trees (cont.)
•
•
•
•
•
Interpret a phylogenetic tree
Explain how to infer phylogenies
Describe different methods to infer phylogenies
Discuss difficulties in phylogenetic analysis
Give an example how phylogenetic tree is used to test a hypothesis
Patterns of evolution
•
•
•
Describe the different between homologous and analogous structures
Explain the difference between convergent, parallel and divergent evolution
Give examples of convergent and parallel evolution
Guest speaker: Dr. Brian Langerhans
EXERCISE
Summary
1
3/3/2014
FOLLOW-UP MINUTE PAPERS
Follow‐up on minute papers
• Lek mating – examples? How does it work?
• Why is female attracted to male display if they don’t indicate male’s ability to survive?
• Runaway selection – more examples
• Next step after creating phylogeny?
• Use of classifying taxa? Tell us about future of a species/predict speciation?
• Phylogenetic trees determine conditions that led to extinctions?
• Coevolution
• Bootstrap values???
2
compete for
Sexual selection
3/3/2014
3
Sexual selection
Sexual selection
3/3/2014
?
4
3/3/2014
CHOOSE THE FITTEST ONE: HONEST SIGNALS Resistance to parasites
Sexual selection
e.g.: carotenoids
signifies resistance to parasites
5
Sexual selection
Sexual selection
3/3/2014
6
Sexual selection
Sexual selection
3/3/2014
7
Sexual selection
3/3/2014
CHOOSE THE FITTEST ONE: HONEST SIGNALS
Access to more resources
8
3/3/2014
Sexual selection
?
Sexual selection
e.g.: larger tail
signifies access to more resources
9
Sexual selection
Sexual selection
3/3/2014
10
Sexual selection
Sexual selection
3/3/2014
11
Direct benefits
Indirect benefits
INCREASE OWN FITNESS THROUGH MATERIAL BENEFITS
‐ Resources (food & territory)
‐ Parental care
‐ Protection from predators
INCREASE GENETIC FITNESS FOR OFFSPRING
‐ Good genes
‐ Sexy sons
EXTREME
exaggerated phenotypes, dance flies presenting empty nuptial gifts, polyandrous females (damselflies, dunnocks) to secure help with parental care, …
Sexual selection
3/3/2014
12
3/3/2014
Sensory bias vs. Runaway selection
pathway already established
random preference e.g.: orange spots resemble orange fruit
(sons express it, daughters inherit preference)
preference for bigger, longer, brighter
…until natural selection puts a cap on it!
EVOLUTIONARY TREES cont.
13
3/3/2014
PATTERNS OF EVOLUTION
One of the most important principles of evolution: Features almost always evolve from pre‐existing features of ancestors
14
3/3/2014
Patterns of evolution
• Homologous vs. analogous structures
• Coevolution
• Convergent evolution
• Parallel evolution
• Divergent evolution
Homologous traits are due to descent from a common ancestor
15
3/3/2014
Homologous vs. analogous structures
COEVOLUTION
closely interacting species exert selective pressures on each other, evolve together in a kind of conversation of adaptations
16
3/3/2014
Evolutionary arms races: Coevolution
•
•
•
•
•
•
Interspecific competition for resources
Predator‐prey
Host‐parasite
Plant‐herbivore
Flower‐pollinator
Sexual conflict
CONVERGENT EVOLUTION (HOMOPLASY)
Evolution of similar features in independent lineages usually from different developmental pathways
17
3/3/2014
PARALLEL EVOLUTION
Evolution of similar features in related lineages by similar developmental modifications
DIVERGENT EVOLUTION
Evolution of increasing differences between groups (can lead to speciation)
18
3/3/2014
Convergent evolution: eyes
Convergent evolution: marcupials & placentals
19
3/3/2014
Parallel evolution: porcupine quill structures
New World
Old World
Convergence: trap‐jaws
20
3/3/2014
BEETLES & HOST PLANTS
Convergence: Cichlids in African lakes
CASE STUDY
21
Biology
• Distribution: North & Central America
• Tetraopes (longhorn beetle, “milkweed beetle”) species affiliated with specific Asclepias (milkweed) species (only few exceptions)
• Tetraopes larvae attack roots, adults feed on upper foliage and flowers
• Females oviposit eggs inside grass stems close to milkweed plant
BEETLES & HOST PLANTS
3/3/2014
Methods
• 29 species • Morphological & allelic data analyzed
• Parsimony tree
BEETLES & HOST PLANTS
Farrell & Mitter 1998
Farrell & Mitter 1998
22
Results
BEETLES & HOST PLANTS
3/3/2014
Results
BEETLES & HOST PLANTS
Farrell & Mitter 1998
Farrell & Mitter 1998
23
Biology
• Echolocation evolved independently in bats & whales (dolphins)
• Involves production, reception & auditory processing of ultrasonic pulses for obstacle avoidance, orientation & hunting
ECHOLOCATION: BATS & DOLPHINS
CASE STUDY
ECHOLOCATION: BATS & DOLPHINS
3/3/2014
Parker et al. 2003
24
Methods
• Genome‐wide sequence data from: – 4 bat species encompassing paraphyly of echolocating bat lineages
– Non‐echolocating bat species
– Echolocating bottlenose dolphin (Tursiops
truncatus)
– 15 additional mammal species
• Maximum likelihood phylogenetic reconstruction
ECHOLOCATION: BATS & DOLPHINS
3/3/2014
Hypotheses
ECHOLOCATION: BATS & DOLPHINS
Parker et al. 2003
Parker et al. 2003
25
Results
ECHOLOCATION: BATS & DOLPHINS
3/3/2014
Results
• Natural selection acted on 3 echolocating
lineages
• Convergence in genes linked to hearing/deafness
• Also: Convergence in genes linked to vision
ECHOLOCATION: BATS & DOLPHINS
Parker et al. 2003
Parker et al. 2003
26
3/3/2014
GUEST SPEAKER
Dr. Brian Langerhans
27
3/3/2014
Recap
• Evolutionary trees (cont.)
•
•
•
•
•
Interpret a phylogenetic tree
Explain how to infer phylogenies
Describe different methods to infer phylogenies
Discuss difficulties in phylogenetic analysis
Give an example how phylogenetic tree is used to test a hypothesis
• Patterns of evolution
•
•
•
Describe the different between homologous and analogous structures
Explain the difference between convergent, parallel and divergent evolution
Give examples of convergent and parallel evolution
• Bahamas Blue Holes
SUMMARY
28
3/3/2014
1. What was the most important thing you learned during this class?
2. What important question regarding what you learned remains unanswered for you? (What would you like to know about next?)
SUMMARY
NAME & DATE 3/3/2014
For next week:
The Beak of the Finch: Read Chapter 12 & 13
Read paper (will be posted)
Draft script due this Friday! (7‐Mar, 5 pm)
29