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Published byMadeline Nicholson Modified over 9 years ago
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Big Idea As the biotic potential of a population increases, the population will incur more environmental resistance as the carrying capacity is reached
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interbreeding assemblages of a single species in an area
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can be expressed by 2 different curves J curve S curve
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TIME POPULATION Population growth at slow rate which increases quickly, because total # of potentially reproducing organisms increases [exponential].
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Population size does have a limit (food, space, etc). After species have a large growth in population, it will level off POPULATION TIME
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the maximum rate at which any individual can reproduce
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factors in the environment that impede population growth
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maximum population that an ecosystem can support
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Populations approaching their biotic potential begin to encounter environmental resistance, whereupon growth slows as the carrying capacity is reached.
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Rapidly growing populations can overshoot, or quickly rise above the environment’s carry capacity.
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This can bring harsh pressures on their own numbers and a population crash, rapid decline or can result.
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Rate of natural increase can be positive, negative, or zero.
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Density Dependent Controls Competition for resources Predation Parasitism disease
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Density Independent Controls Effect a population regardless of size: - floods - hurricanes - severe drought - fire - habitat destruction - pesticide spraying
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R-Strategist Species Have a capacity for a high rate of population growth Tend to be opportunists; reproducing and dispersing rapidly when conditions are favorable Offspring mature quickly
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K-Strategist Species Reproduce late and have few offspring with long generation times Offspring mature slowly Tend to live longer
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human hydra dandilion
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the populations living and interacting together in an area
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Sexual Dimorphism differences between males and females of the same species clearest dimorphism is between gamete size (leads to behavioral differences)
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Females gametes: large, nutrient-filled, expensive to produce, limited in number and produced infrequently. Male gametes: small, no nutrients, cheap to produce, constantly made
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Sexual Selection trait that gives an advantage in acquiring mates and producing offspring occurs in two forms: 1. out-compete members of the same sex for access to mates i.e. Madagascar Tortoise 2. evolve preferences for desirable qualities in potential mates i.e. Blue Footed Booby
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Female Reproductive Strategy seek quality not quantity look for certain criteria Physical Features: size and strength which confer dominance and thus preferential access to resources. Behavioral Features: most desirable (alpha) males.
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Male Reproductive Strategy less choosy seek quantity will take any sexual opportunity compete with other males for access to females small number of males will achieve the most matings, while many males will never mate.
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Parental Investment(PI) Any investment in an offspring that increases the offspring’s chances of surviving (and hence reproducing) In most species, females invest heavily in their offspring while males do not.
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WOMEN POWER! female is always 100% certain that an offspring is hers …. male cannot be sure to avoid ‘cuckoldry’ male must continually provide resources, PI, and protection so the female won’t be tempted to cheat
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Blue Footed Booby mating dance
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Penguins life partner
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Green Winged Teal gang rape females many times killing her in the process
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Sea Lions harem non alpha males= rape
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Lions harem take over other harems
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Chimpanzees Promiscuous female children stay with mom until teens
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Peacocks sexual dimorphism
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African Elephants taste female’s urine to test for estrous larger more alpha male preferred
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after copulation, male and female may remain connected for up to a half hour
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