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Unformatted text preview: Coevolution 1. Discuss the role of signals in coevolution. What types of signals are passed between animals? What are the adaptations that permit these signals to be sent and received? What is the role of deceitful vs honest signals in the systems we have discussed? Are there common patterns that you can identify?- role: trait species A has evolved in response to B which was previously affected by A - types: visual, chemical- adaptations: morphological relations; signals between predator and model, correlation between signal and message; learned response to signal by predator- avoidance; sensory- role of deceitful v. honest signals: species A to help itself; deceit means that the species does not have to invest energy into making a benefit- common patterns: suit specific functions 2. Competition and resource partitioning are key factors in examining coevolutionary patterns. Identify those situations, and understand their role in producing various phenomenon in the examples we have discussed. Flowers and Birds- competition is that both birds and plants fight own species for each other- birds need food while plants need pollinators- birds and plants share each other since the beak shape and flower shape suit each other Tanins and insects- resource partition for energy going into making tannins in the leaf 3. In coevolutionary systems, each of the participants experiences costs and benefits in the interaction. What are they and why do they occur? Cowbird with Flies- cost: decreases host survivorship- benefit: rids nest of parasitic fly Mimicry- poisonous snakes v. snakes that look like them- cost: predators don’t recognize poisonous snakes because of look a like- benefit: look a likes get recognized as poisonous 4. Construct imaginary scenarios leading to the 3 models of parasite-host interactions, and understand why each evolves to a particular state. Arms Race- examples are bacteria and bacteriaphages; AIDs- occurs when virulence of the parasite is too low Prudent Parasite- mixoma virus in rabbits- virus killed rabbits too fast; too efficient which meant that the virus was unable to spread well- the viruses that acted slower had a trait that was selected for since they could spread more Incipient Mutualism- parasite develops a beneficial effect on host- opposite of arms race- host doesn’t kill parasite as fast so parasite can spread- an example is the cowbird 5. Plant species 1 is consumed by insect A, while plant species 2 in consumed by insect B. What sort of evidence from lab experiments would lead you to believe this was/was not, the result of an arms race type scenario? Dumb ? 6. Why does coevolution occur? because it helps a species; result of random processes Succession 1. Identify the characteristics of Gleasonian vs Clementsian models of succession....
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- Spring '06
- Evolution, Measurement of biodiversity, Clements