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

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

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

Neutralism

Commensalism e.g. Barnacles on whales

Amensalism Dinoflagellates cause Red Tides

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

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

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.

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

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

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.

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

Obligate Mutualism Termites & their gut flagellates

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)

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.

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

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

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

Paramecium Competition P. aurelia P. caudatum

Carrying capacity

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

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

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

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

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

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

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

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

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

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

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

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

Results of Competition c) Resource partitioning & Character displacement

Competition Extinction Co-existence

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

Next Time Intraspecific Competition