BIOL 208 Midterm One Material

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Biology (Biological Sciences)
James Cahill

Biology 208 Study Notes Class Notes  Evolution is the change in allelic frequency within a population over time  Evolution is common.  Genetic drift is the number one cause of evolution.  Fitness landscapes illustrate that natural selection does not optimize. In fat, it favors higher fitness over other aspects.  Founder effect – the movement of a small number of individuals into a new area. It results in a decreased level of heterozygosity.  There are stabilizing, directional, and disruptive forms of selection.  An ecocline is genetic in basis and occurs in a gradient.  An ecotype may or may not be genetic.  Biological species concept – a species is a group of reproductively isolates organisms. It is only accurate with regards to vertebrates.  Phylogenetic species concept – based on the pattern of history, it uses evolutionary past to determine species. The problem is that it is completely arbitrary and not testable.  There is no correct definition of a species.  Mechanisms of isolation include ecological, temporal, behavioral, mechanical, hybrid inviability, and hybrid sterility.  Biomes – classification of large areas of the earth.  Circulation – movement of air promotes deserts and forested areas.  Altitudinal gradient – as you move up higher above sea level, there is a drop in temperature and an increase in precipitation.  Where does variation come from? o Microhabitat – sub-environment that produce different conditions to survival. o Human impact o Altered physical landform o Introduction of non-native species o Herd behavior o Physical factors such as pH, soil acidity, nutrients, etc.  A graph of ‘# of species’ vs. ‘Area’ could produce different graphs. If the curve saturates quickly, then there are few variations within the habitat. A secondary jump in the graph indicates a new ecological zone.  Latitudinal gradients - there are more groups near the equator than farter away. This is a general trend. At the equator, there is less climatic variability, more space, the land is older (because of glacier movement), and it is connected to more land.  Theory of Island Biogeography – by MacArthur and Wilson. The theory focuses on prediction based on area and isolation. These two men created a neutral theory, like the Hardy-Weinberg Theory. o Their graph shows an intersection between immigration and extinction. o It is an equilibrium based model. o The value of ‘T’ indicates the turnover at equilibrium. o Their basic theory has been supported by various experiments.  Island Biogeography Theory can also be used on land, such as in areas of mountains or clear-cut forests.  Principle of reserve design exists. In general, one large is better than several small. This is because of edge effects.  Performance curves – depict the range of tolerances with which an individual can survive, grow, and reproduce.  Law of Toleration – the performance of an organism is determines based on maximum performance and environmental conditions.  Specialist – high performance under a specific set of abiotic conditions.  Generalist – high performance under an array of abiotic conditions.  Hutchinson – the niche is an “n-dimensional hypervolume”.  Fundamental niche – conditions which allow the species to survive  Realized niche – the reality of the species.  Time-Energy charts show that organisms spend time and energy on growth, maintenance, activity, and reproduction. o If a species uses more energy and time on maintenance, it may be living outside of its niche.  Albedo – the reflection of light of a particular area.  Hs= H m +/H cd+/-Hcv+/-H r-H e  In the arctic, plants are slow growing, grow low to the ground, have leaves perpendicular to the sun, and have a darker body.  In the desert, there is a decreased surface area of leaves, plants are tall, round, and close to the ground. They are also parallel to the sun to minimize exposure.  Poikilotherm – body temperature varies over time.  Homeotherm – organism which has constant body temperature.  Endotherm – heat is derived from metabolic processes.  Ectotherm – heat comes from other sources.  Thermal Neutral Zone – the range of temperatures at which the body can cope without additional metabolic regulation.  Opportunity Cost – a cost that isn’t measurable in terms of energy.  Size of carnivore and detritivore is dependent on si
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