Divergence of populations Need to prevent breeding o Two main ways Pre zygotic

Divergence of populations need to prevent breeding o

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Divergence of populations Need to prevent breeding o Two main ways: Pre-zygotic isolating mechanisms Geographic separation: individuals are separated by distance and cannot natural reproduce because of it
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Ecological separation: Differences in preferred areas result in lack of interaction/reproduction Behavioral separation: difference in mating behavior Temporal separation: differences in timing of mating Mechanical separation: physically not able to reproduce Gamete isolation: gametes cannot fuse Post-zygotic isolating mechanisms Hybrid not viable: not develop properly Hybrid not viable: doesn’t survive in nature Hybrid cannot reproduce offspring itself Reproductive isolation - Rates of Evolutionary Change o Gradualism: over time, species are gradually changing, slow change o Punctuated equilibrium: quick, dramatic changes over time This is different from one group of species to another - Important to think about ecology and evolution at the same time - Organisms always trying to do 3 things: o Acquire nutrients o Avoid being eaten o Reproduce  these forces drive ecological and evolutionary change - Co-evolution: the evolutionary “arms race” or the “Red Queen Hypothesis” o Organisms evolve with others – interaction o Trying to outdo each other, but neither is winning o As time goes on, organisms are accumulating traits that are better suited for its environment 2/24/15 Hybrids can do this
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- Ecology effects evolution o Predators act as agents of evolution - Evolutionary effects of human fragmentation o Not directly effecting it, but effecting it by changing the landscape Physiological Ecology - Interactions between organisms and their environment that influence their survival and geographic range - Organisms have multiple strategies for stress from environment o Stress : condition in which environmental change results in a decrease in physiological processes resulting in a decrease in possible reproduction, survival, and growth o Acclimation : response to stress, short-term changes to an individual o Adaptation : long term genetic response to environmental stress - Resource Utilization Function (RUF) o One dimensional measure of physiological performance of species along a resource gradient o Shape of curve tells you a lot about species and can help predict what will happen over time - Ecological niche o Activities and relationships of an organism constrained by physical and biological processes o Vs. Habitat: Actual place often described by vegetation o One dimensional niche too narrow o Described by MANY factors o Fundamental vs. realized niche Fundamental : entire set of conditions under which an organism can live and reproduce Realized : actual conditions in which organism lives - Role of temperature for organisms o Most organisms have a physiological optimal temp where they work best
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- Physiology of desert living o How does the environment constrain an individual o Ex: desert iguana
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