1. What kind of selection is this?
Directional
Stabilizing
Disruptive
Eliminative
No way to tell 45

2. This is negative selection— elimination of “unfit” genotypes.

3. Relations Between Species
Neutralism Species A B
Mutualism A B
Competition A B
Predation A B
Parasitism A B
Commensalism A B
Amensalism A B + + _ _ _
Predator
Prey + _
Host
Parasite + O
Commensal
Host + _ O
Most of these interactions influence the evolution of a species

4. Neutralism

5. Commensalism
e.g. Barnacles on whales

6. Amensalism
Dinoflagellates cause Red Tides

7. Mutualism
Mutualism= 2 organisms interact where both derive a fitness benefit (increased reproductive output. +
A B +

8. Types of Mutualistic Relationships
Resource-Resource Relationship =
resources are exchanged (usually nutrients)
e.g. Mycorrhizae = plant roots -- fungi
Carbohydrates to fungi & soil minerals to plant

9. Types of Mutualistic Relationships
Resource-Resource Relationship =
e.g. Nitrogen-fixing in legumes
(peas, beans, peanuts, alfalfa)
Root nodules with Rhizobia bacteria
Bacteria get carbohydrates from plant and plants get nitrogen.

10. Types of Mutualistic Relationships
2) Service-- Resource Relationship =
Services are exchanged for resources
(usually nutrients)
e.g. Pollination –nectar or pollen are traded for pollen dispersal
e.g. Seed dispersal --squirrels get nuts and nuts are dispersed

11. Types of Mutualistic Relationships
3) Service--Service Relationship =
Services are exchanged
e.g. Sea Anemones and
clown fish
Sea anemones protect clown
fish against predators & anemone fish protect anemone against the
butterfly fish

12. Facultative vs. Obligate Mutualism
Facultative = the partners aren’t necessarily completely dependent on each other.
Boran people of Africa, and the honey guide.
Greater honey guide leads people to bee colonies. Borans use fire and smoke to drive off the bees, break open the nest and remove the honey, but leave larvae and wax behind. The bird gains access to larvae and wax. The use of fire and smoke reduces the bird's risk of being stung, and humans increase accessibility of nests.

13. Types of Mutualistic Relationships
Facultative
e.g. Protection from predators—ants protect aphids from lady bug beetles and receive sugar water (sap) in return

14. Obligate Mutualism
Termites & their gut
flagellates

15. Mutualism Three-way mutualism (ants, caterpillars, flowers)
Flowers produce nectar and get pollinated by caterpillar. Caterpillar gets nectar, spreads pollen, & has nectar glands. Ants drink nectar and protect caterpillar and flower from herbivores and predators.
Three-way mutualism (ants, caterpillars, flowers)

16. Mutualism and Cheaters
e.g. Some flowers don’t produce nectar and pollinators can’t distinguish them from those that do.
e.g. Some cleaner fish don’t just clean parasites off of their clients but sneak a bit of mucus or skin as well.
What is to stop this from happening?
If this happens on a large scale then this can evolve into commensalism or parasitism.

17. Competition and Selection
Resource competition
Interspecific = between species
A B
Intraspecific = within a species
A A _ _ _ _

18. Competition and Selection
Strategies of Interspecific Competition:
Scramble competition = same resource at different times --- moose and rabbits

19. Competition and Selection
Strategies of Interspecific Competition:
2. Contest competition = same resource at same time ---jackals and vultures ---hyenas and lions

20. Paramecium Competition
P. aurelia
P. caudatum

21. Carrying capacity

22. Draw the graph that would result.
Paramecium Competition
P. aurelia
Predict what might happen when these species are grown together in the same environment.
Draw the graph that would result.
P. caudatum

23. Results of competition
One species wins and the other becomes extinct Competitive Exclusion Principle complete competitors cannot co-exist if resources are limited
(Gause’s Principle)
Paramecium figure
Wood warblers Fig 46-6
Starfish predation slide

24. Results of competition
2. Co-existence shared habitat a. Shifting advantages e.g. flour beetles
Paramecium figure
Wood warblers Fig 46-6
Starfish predation slide

25. Results of competition
Co-existence
b) Populations are maintained below competitive levels e.g. Influences such as disease (parasitism) and predation
e.g. African antelope and predators
e.g. Starfish
Paramecium figure
Wood warblers Fig 46-6
Starfish predation slide

26. Key-stone species Divebums.com/FishID/Pages/giant_spined_star.html
Divebums.com/FishID/Pages/sunflower_star.html

28. Keystone species = a species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass.
e.g. beaver transforms its territory from a stream to a pond or swamp.
e.g. elephants destroy trees, making room for the grass species. Without these animals, much of the savanna would turn into woodland.
Divebums.com/FishID/Pages/giant_spined_star.html
Divebums.com/FishID/Pages/sunflower_star.html

29. Results of competition
Co-existence
c) Resource Partitioning =
When two species partition (divide) a resource based on behavioral or morphological variation and thereby reduce competition.
Paramecium figure
Wood warblers Fig 46-6
Starfish predation slide

30. Resource Partitioning =
Habitat partitioning e.g. Warblers using different parts of the tree
Aves.net/photo-index/wood-warblers.html

31. Resource Partitioning
Wood warblers
Aves.net/photo-index/wood-warblers.html

32. Resource Partitioning
2) Temporal Partitioning e.g. Hawks and owls feed at different times of day
Aves.net/photo-index/wood-warblers.html
Prairie falcon
Great Horned Owl

33. Resource Partitioning
3) Seasonal Partitioning
e.g. Mayflies and other stream invertebrates emerge at different times of the year from the emergence times of their potential competitors
Aves.net/photo-index/wood-warblers.html

34. Resource Partitioning
Food type or foraging strategy partitioning
e.g. Large cats with antelope (sit-and-wait vs. active chase)
Aves.net/photo-index/wood-warblers.html
Leopard
Cheetah

35. Results of Competition
c) Resource partitioning & Character displacement

37. Competition
Extinction
Co-existence

38. Competition Extinction Co-existence Shifting advantages Population
Low
Population
density
Resource
partitioning

39. Next Time
Intraspecific Competition