Lecture 24 Evolutionary Ecology

Question 1

Eco-Evolutionary Relationships

Answer 1

• Evolution and Ecology
  have reciprocal effects on
  each other
• Phenotypes (traits)
  improve survival or
  reproduction (fitness) in a
  given environment
• Evolutionary change in
  phenotypes has feedback
  effects on ecological
  dynamics

slide 21-22

Question 2

Coevolution

Answer 2

• Species interactions
  influence natural
  selection!
• Coevolution: the
  evolution of interacting
  species in response to
  selection imposed by
  the other
• Can be result of
  positive or negative
  interactions
• Bird beaks & food
• Predator-prey
  antagonism

slide 23-25

Question 3

Coevolution: Predators and Prey

Answer 3

Adaptations of predators and prey are refined through natural selection

slide 26

Question 4

Coevolution: Predator Adaptations

Answer 4

Most predators have
acute senses to find
and identify prey.

Predator evasion»_space; Prey detection

slide 27-31

Question 5

Coevolution: Predator Defenses

Answer 5

Prey evolve in response to avoid being eaten
* Behavior (hiding, fleeing, herding, schooling, alarm signals)
* Active self defense (large mammals defending young)
* Mechanical (quills, spines, protective armor)
* Chemical/Toxins (synthesized or acquired from plants they eat)
* Coloration

• Cryptic coloration & camouflage: patterns,
  colors, and body shapes allow prey to blend in
• Animals with chemical defenses often have
  aposomatic coloration (warning coloration)
• Mimicry & color can trick or disorient predators
  to deter attack

slide 32-34

Question 6

Coevolution: Warning Color & Mimicry

Answer 6

slide 35-36

Question 7

Coevolution: “Red Queen”

Answer 7

• Failure to catch prey selects for smarter and more skilled predators…
• Which in turn select for faster prey that can avoid capture.
• Prey must be constantly be adapting to keep up with predator adaptations

slide 37

Question 8

Coevolution: Behavioral Defenses

Answer 8

• Population-level defenses: coordinated behavior defends the population
• Chemical or vocal warnings
• Massive production of seeds or offspring all
  at once after a long interval…
  too many to all get eaten!

slide 38-39

Question 9

Eco-Evolutionary Relationships

Answer 9

slide 40

Question 10

Adaptive Radiation

Answer 10

period of rapid evolutionary
change in which one species
diversifies into many new species
whose adaptations allow them to
fill different niches

• A type of range expansion that
  involves evolution!
• Large-scale adaptive radiations
  occurred after each of the big 5
  mass extinctions to fill the many
  unoccupied niches
• Other adaptive radiations
  happened with:
• Evolutionary innovations such as
  seeds or armored body coverings
• Colonization of new regions, longdistance dispersal

Key features:
1. Common Ancestor
2. Trait-environment
relationship
3. Fitness advantage
4. Rapid bursts of speciation

slide 41-43

Question 11

Adaptive Radiations: African Ciclid Fish

Answer 11

• Opportunity & Specialization over 2 million years
• Diversified to feed in different ways with
  specialized tooth and mouth adaptations
• Estimated rate of speciation: 1 every 46 years!

slide 44-45

Question 12

Adaptive Radiations: Hawaii

Answer 12

• Multiple invasions followed by
  speciation events led to multiple
  adaptive radiations of species
  found nowhere else:
  Silverswords, honeycreepers,
  drosophila, spiders

Question 13

Adaptive Radiations: Hawaiian Silverswords

Answer 13

slide 47 - 48

Question 14

Adaptive Radiations: Anolis lizards

Answer 14

Habitat specialization & adaptive
morphology enables rapid &
convergent speciation

slide 49-50

Question 15

Rapid Evolution

Answer 15

We see nothing of these slow changes in
progress, until the hand of time has marked
the long lapse of ages.
-Darwin, 1859

slide 51-55