Coevolution. Between plants and animals A relationship develops between two organisms such that, as...
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Transcript of Coevolution. Between plants and animals A relationship develops between two organisms such that, as...
Coevolution
Coevolution
• Between plants and animals
• A relationship develops between two organisms such that, as they interact with each other over time, each exerts a selection pressure on the other.
• Evolution of each becomes interdependent on that interaction
Coevolution
• “a reciprocally induced evolutionary change over time between two organisms”
Types of relationships...
A B
Neutral 0 0 Neither population
exerts influence on the
other
Mutualism + + Both populations
benefit
Commensalism + 0 One population
benefits, other neutral
Predation + - Predator benefits, prey
does not
Parasitism + - One benefits, host is
affected negatively
Symbiotic relationshipAnts and Acacia tress
Beltian bodiesthorns
nectaries
Ants, caterpillars and acacia
How is it a mutual relationship?
• Ants provide tree services too! Attack herbivores, chew up nearby trees so Acacias aren’t in shadows.
• Tree provides ants- nectar for food, thorns for nest, protein rich Beltian bodies (on leaf tips)
Example #2- Figs and Wasps
synconium
Why is it mutually beneficial?
• Reproductive system of both are tied together.
• Fig benefits from pollination
• Wasps benefit by having a food source for larva
Some primate examples
• Mutualism– Seed dispersal– Pollination
• Predation– Seed predation
• Parasitism– Strangling fig– Polyspecific associations
Plants and Seed Dispersal
•Processing techniques•Dispersal location•Seeds’ Mechanical properties •Shape- Oval seeds•Size- large seeds•Color?
Processing technique
Damage seedMolars used
Undamaged seedIncisor used
brown lemur Sifaka
Dispersal location
• Not under the tree- tree shadow (why?)
• Lemurs have short gut passage rate (less than 30 minutes)
• So there must be some travel away from parent tree.
Seeds fate?
• Not get eaten by secondary predator (rats)
• Buried or in enough feces to germinate
• Seedling survival (limited- 1 out of 4000 seeds)
Seed properties
• Should be resistent to chewing
• Oval shape facilitates swallowing whole
• Color attractive to primate (bright?)
• Large to prevent damage
Pollination
• Morphological adaptations
• Flower size, color, smell
• Number of plants visited
• Flower handling
Morphology
• Muzzle length• Tongue (lemur
picture)
Ruffed lemur
Mouse lemur
Flower morphology
• Large flowers• Tough petals• Produce copious
nectar• Brightly colored• Smell strongly
Traveler’s palm
Visits and handling
• Must visit more than one tree with flowers to transfer pollen
• Need to handle flowers carefully so don’t destroy reproductive parts.
Seed PredationSeed Predation
Fruit and seeds
Eats seeds
protects seeds
Fruits simultaneously
Still eats seeds but not all seeds
Thwarts protection
Parasitism
Strangling fig Polyspecific associations- not trueCoevolved relationships
Summary tableSummary tablePollination Seed-Disp Seed- Pred.
Target Nectar Fruit, Seeds Seeds
Cues smell, color size, color,smell
size, color,smell
Adv. to plant
pollentransfer
Move seedsaway
None
Adv. to primate
Food Foodalthoughseeds notuseful(heavy)
Food
Are these really examples of Coevolution?
??
Seed Dispersal: Not a tight relationship
• Seeds fate once on the ground?
• Seedling survival?• Not dependent on
one organism for dispersal- secondary dispersers
Dung beetle
Agouti
Pollination: not a tight relationship
• Flowers can rely on many different pollinators (insects, bats, birds, mammals)
• BUT- Madagascar- limited pollinators (few bats, birds)
Once upon a time...
• In general, a hard relationship to document- a bit of “story” telling
• Evolutionary Story Telling- the Angiosperm hypothesis (Handout in coursepack)