FW 104 Wildlife Ecology and Conservation week 3
FW 104 Wildlife Ecology and Conservation week 3 FW 104
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This 9 page Class Notes was uploaded by Devrrae Russell on Thursday September 8, 2016. The Class Notes belongs to FW 104 at Colorado State University taught by Ann Randall in Fall 2016. Since its upload, it has received 3 views.
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What is Karma?
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Date Created: 09/08/16
September 6, 2016 Justin reeves Species interactions in the community ● Coevolution ○ Species that interact over long time period influence each other’s traits via natural selection ○ Plants and pollinators ○ Predator prey ● Predation ○ Predator offense ■ Ambush ● Sit and wait ■ Stalking ● Quietly following prey ■ Cooperative hunting ● Hunting in groups ○ Prey defenses ■ Speed ■ Agility ■ Armor ■ Weaponry ● Thorns ● Stingers ● Poisons ○ Both use camouflage ○ Negative feedback system results in cycles Symbiotic relationships close relationships often highly dependent ● Parasitism ○ Slow form of predation ○ Can be evolutionarily stable as long as the host population is not killed off ● Mutualism ○ Both species benefit ○ Positive feedback cycle; if one does well the other does well ○ Ants and aphids ○ Hummingbirds and flowers ● Commensalism ○ I help you; you do nothing for me ○ Water buffalo and egrets ○ Commensal species may loosely follow trends in host density, but not vice versa ● Competition ○ Two organisms fight each other fighting for the same resources or niche ○ Trout ○ Buffalo and livestock ○ Positive feedback: they both decline till one shifts niches or dies off Community ● Coexisting, interdependent populations of different species in a particular location Energy ● 2nd law of thermodynamics ○ As food is passed from one organism to another, the potential energy contained in a food source Food chains ● Pathways over which energy flow through an ecosystem ● Trophic levels ○ Levels in a food chain ● Only 1/10 of energy is passed on September 8, 2016 Components of population dynamics Behavior mating systems ● Polygamy ○ Having many mates ● Polyandry ○ One female to several males ○ phalarope ● Polygyny ○ One male to several females ○ elk ● Monogamy ○ Seasonal or life long mates ○ Bald eagle ● Promiscuity ○ Indiscriminate mating ○ rabbit Population abundance ● Number of individuals of a species that occupy a particular area ○ Referred to as N ● How it changes ○ Birth or natality ■ Number of births per individuals in a population over a specific period of time ■ Fecundity the number of eggs produced per female ■ Fertility the percent of the female eggs that are fertile ■ Production the actual number of surviving offspring produced by a population ■ Recruitment the number of new individuals reaching and breeding age in the population ■ Fittness the relative ability of an individual or population to survive,reproduce, and pass on genetic material in an environment ○ Death or mortality rate ■ The number of deaths per number of individuals over a specified time period ○ Dispersal movement of individuals from one location to another ■ Immigration rate ● the number of animals coming into the population over a specified period of time ■ Emigration rate ● The number of animals leaving a population over a specified period of time How many should we harvest? ● Population growth curves helps us understand how much fishing or hunting effort a population can sustain ● Exponential growth ○ Yeasts in labs ○ Island caribou ○ Invasive species ○ humans Biotic potential ● Maximum rate at which a population can grow when no resorsce are limiting ○ Referred to as r ● r = b+d “R selected” life history strategies ● Adapted for rapid population growth ● Reproduce rapidly, high mortality, rapid turnover of generations, good dispersal little effort in young, many offspring , poor competitors ● Better adapted for harsh/ unstable habitat conditions Do populations increase forever? ● No, there is no exception to the rule that every organic being increases at a rate so high that if no destroyed, the earth would soon be covered by progeny of a single pair ● K= carrying capacity = max # of individuals in a population ○ Depends on habitat ○ K is dynamic and changes “K selected” life histories ● Competition for resources is intense, good competitors, low reproductive rates, few offspring, more effort into young ● Adapted for a more stable environment ● More endangered species are k selective Harvesting populations ● Natural (wild) populations are harvested by removing individuals ● Size of the harvest assessed by numbers ,biomass, or both ● A goal of management ○ Ensure the largest harvest that can be sustained over time ● Depending on the species and many other factors ● MSY = populations maintained at ½ K will results in the max number of animals that can be harvested each year ○ Some environments are much harder to assess and monitor ○ Major changes such as disease and new technology ○ Different countries have different values and regulations ○ Politics ○ Dynamic estimate ○ Tragedy of the commons Density dependent factors ● Factors that cause higher mortality or reduced birth rates as a population becomes more dense. ○ Resources ○ Disease ○ predation Desity independent factors ● Factors that operate independent of the population desity ○ Weather ○ Accidents ○ Natural disaters