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Week 1 Ecology Chapters 52-54
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Dispatch—Make 3 observations on the distribution of biomes
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Goal and Name same side Line up for pic
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Descending air absorbs moisture Ascending air releases moisture
Air Cells Descending air absorbs moisture Ascending air releases moisture
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Group whiteboard Draw a mountain
Predict what happens to air as it rises over a mountain
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How mountains affect rainfall. RAINSHADOW
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Show the O2 and CO2 cycle Be as detailed as possible
One person will be picked to present
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Nitrogen cycle
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Dispatch If your group needs to presentfind a group to listen and approve you If your group is approved listen to group’s nitrogen presentation if they have all components, tell me
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Nitrogen Cycle Animation
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Population vs. Community
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Population Ecology QUESTIONS: What is a population?
What affects the size a population can get?
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Population A population is a group of individuals of a single species that simultaneously occupy the same general area. Two characteristics that affect populations are ________ and _______
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Population characteristics
Density~ # of individuals per unit of area •counts •sample size estimate •indirect indicators •mark-recapture Dispersion~ pattern of spacing •random~ unpredictable, patternless spacing (a) •clumped~ patchy aggregation (b) •uniform~ even spacing (c)
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Density is the result of a dynamic interplay
Between processes that add individuals to a population and those that remove individuals from it
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Births and immigration add individuals to a population.
PopuIation size Emigration Deaths Deaths and emigration remove individuals from a population.
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Activity: Make a graph for a bacterial population and an elephant population
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Dispatch—Get a textbook
Draw an exponential growth curve? What species exhibit this growth? What about the environment would make an r species exhibit exponential growth? Describe what a population’s carry capacity is and what it means to the population? Compare and contrast density- dependent to density-independent factors? Take our calendar and tell your tablemates 3 upcoming deadlines Pick up a growth half sheet and a paper that says class set Wilderness Park 9:30 TOMORROW
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Population Growth Models
Exponential model (blue) • idealized population in an unlimited environment (J-curve); r-selected species (r=per capita growth rate) Logistic model (red) •carrying capacity (K): maximum population size that a particular environment can support (S-curve); K-selected species
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Demography: factors that affect growth & decline of populations
Birthrate (natality, fecundity)~ # of offspring produced Death rate (mortality) Age structure~ relative number of individuals of each age Survivorship curve~ plot of numbers still alive at each age
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R vs. K survivorship curves
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Population life history “strategies”
r-selected (opportunistic) Short maturation & lifespan Many (small) offspring; usually 1 (early) reproduction; no parental care High death rate Ex:________ K-selected (equilibrial) Long maturation & lifespan Few (large) offspring; usually several (late) reproductions; extensive parental care Low death rate Ex:____________
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Population limiting factors
Density-dependent factors •competition •predation •stress/crowding •waste accumulation Density-independent factors •weather/climate periodic disturbances
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Community Ecology QUESTIONS: 1) What is a community?
2) Who are the members of this community? 3) What is a food chain?
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Differences in Community structure
Community~ an assemblage of populations living close enough together for potential interaction. Many different ______. Communities differ dramatically in their species richness (number of species) & relative abundance of different species
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How can we account for the species found together as members of a community?
2 Hypotheses: •Individualistic~ all the species just happened to live in the same area b/c they all had similar abiotic requirements. Example they all needed same temperature, rainfall, soil type which is why they live in the same habitat. •Interactive~ all the species are locked into association by mandatory biotic interactions. Species are found together b/c they have formed relationships +, - and o.
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Between Species TASK: Add a column to the right and give an example of each type of interaction
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Activity: Interaction Charades
I will give your group an interaction and you act it out
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