ISB 202 1nd Edition Lecture 11 Outline of Last Lecture I. Evolution Outline of Current Lecture II. Adaptations to avoid PredationIII. SymbiosisIV. Types of SelectionCurrent Lecture- Habitat vs Nicheo Habitat-Addresso Niche-Occupation - How do species interact?o Predator / Prey Relationshipso Symbiosiso Competitiono Co-EvolutionAdaptations to Avoid Predationo As predators become more efficient, the prey evolves defenses (thorns, toxic chemicals, etc.)o Coevolution: Over time predator and prey evolve in response to one another - Species with chemical defenses often evolve warning colorationo Batesian mimicry: Harmless species mimic the warning coloration of harmful species to gain protection o Mullerian mimicry: Two harmful species evolve to look alike - Evolved Mechanisms to Avoid Predationo Defense Mechanisms o Camouflage : Cryptic ColorationSymbiosis- In symbiosis two or more species live intimately together with their fates linkedMutualism: both organisms benefit from their association (ex: a fungus and an alga combine to make a lichen)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Commensalism: one species benefits while the other neither benefits nor is harmed (ex: a bromeliad growing on the trunk of a tree absorbs water and nutrients dripping down the tree trunk without harming the tree)Parasitism: dependency of the parasite on its hostMutualism: both benefit- Parasitismo One benefitso One is harmed- Commensalismo One benefitso The other is neither helped or harmed- Competition o Intraspecific: within the same specieso Interspecific: between different species (niche overlap)- Resource partitioning: species co-exist in a habitat by utilizing different parts of a single resource (Ex: Birds eat insects during the day and bats eat insects at night)- Sympatric Speciation: organisms continue to live in the same place but become isolated by someother means (Ex: Some apple maggots preferred hawthorns over apples. This prevents them from breeding with the population from which they originally came and effectively creates a newspecies)- Once isolation occurs the two populations begin to diverge due to:o Genetic drift: chance events that cause genes to be lost from a population.o Selection pressure: the selection pressures on the two populations are different on the populations are isolatedTypes of Selection- Directional selection: one trait is being favored and the other is being eliminated so the population shifts toward one trait- Stabilizing selection: range of a trait is narrowed- Disruptive selection: traits diverge toward the two extremesGenetic Drift: Random change in allele frequencies in a small breeding populationGene Flow: Movement of alleles between local populations due to migration and subsequent
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