Lecture 8: Species Interactions II

Define keystone species

 species that has a disproportionately large effect on its environment relative to its abundance

What are the 3 types of keystone species 

1. Keystone predators (e.g. wolf, sea otter)

2. Keystone consumer/prey species (wildebeest, krill)

3. Ecosystem engineers

   1. Autogenic, aka “Foundation” species (e.g., coral, oysters) – create an environment with their own physical structures

   2. Allogenic (e.g. gopher tortoise, beaver) – alter the environment with mechanical changes

Define Foundation species (autogenic engineers)

Species that make their own habitat and support other species 

Allogenic engineer

an organism that modifies its environment by mechanically changing living or non-living materials from one physical state to another. 

Ex. beaver

true or false. Predatory-prey cycling causes linear population increase 

False, causes oscillating population increase.

Consumer resource interaction(ex. predation, parasitism, herbivory, etc (+,-) ) cause evolutionary arms race. What is the evolutionary arms race?

prey continually evolve better defenses and predators continually evolve better offenses

list the 4 categories of evolutionary defense

Behavioral, crypsis, structural, chemical, mimicry

list behavioral evolution defenses

1. Alarm calling

2. Spatial avoidance

3. Reduced activity

4. Vigilance

5. Evasion

6. Harassment

7. Distraction

8. Evasive running 

9. Predator harassment - bothering predator to deter the predator from attacking

define crypsis

camouflage

define what structural evolutionary defenses are and give examples

1. Mechanical defenses

• Quills, stingers, thorns, shells

list chemical evolutionary defenses

1. Spray foul smelling or toxic chemicals

2. Store toxins in body

3. Warning coloration (aposematic)

   1. Predators associate odd colors with distastefulness

defining aposematic

warning coloration

define mimicry (evoltionary defense)

Looking like another animal or plant to stay safe

what are counter adaptations that predators have to combat evolutionary defenses

1. Alter behavior (e.g. learning, specialization)

2. Camouflage

3. High-speed locomotion

4. Resistance to toxin

5. Form search image