Lesson Topics covered:  Biosphere, lithosphere, hydrosphere  Nitrogen cycle,  Characteristics of population  Exotic species

Nitrogen fixation process Denitrification process Artificial fixation of N 2 using fossil fuel Fertilizer applications THE NITROGEN CYCLE

Nitrogen cycle- key terms to know Complete Nitrogen cycle HW: Matching onto diagram ProcessesDone by 1.Nitrogen fixation = convert N 2 into NH 3 Nitrogen fixing bacteria 2. Nitrification = converts NH 4 + into NO 2 - and then NO 3 - Nitrifying bacteria 3. Denitrification = converts NO 3 - back to N 2 Denitrification bacteria N2N2 nitrogen gas NH 3 ammonia gas NO 2 - nitrite ion NH 4 + ammonium ion usable forms of nitrogen by most living things NO 3 - nitrate ion

Nitrogen fixation process Denitrification process Artificial fixation of N 2 using fossil fuel Fertilizer applications THE NITROGEN CYCLE

Characteristics of a population Exponential (unrestricted) growth: The growth rate of a population accelerates rapidly producing a J-shaped curve when plotted Occurs when resources are abundant Short-lived phenomenon

is reached The # of rabbit births = # rabbit deaths The population is said to be at equilibrium Carrying capacity is the maximum number of individuals that an ecosystem can support indefinitely. Equilibrium: the number of individuals of a population stays the same over time Why does this happen?

Limiting factors are any resources that is in short supply (or limited) Any abiotic and biotic factor can be a limiting factor on a population. Examples of limiting factors? What can limiting factors do to a population? -help prevent over- population Can most populations be affected by more than one factor at a time? - YES

What does this graph tell you about the hare and lynx population? Why does such pattern exist? Case study- Snowshoe hare and Lynx population cycles

What does this graph tell you about the hare and lynx populations? - Hare and lynx population decrease and increase every 10 years - Lynx population closely follows that of the hare

How can we explain such pattern in the hare- lynx population cycles? 1.As hare population increases, the lynx can capture hares more easily. Thus, lynx population increases. 2.Increased lynx number causes hares to decrease. Thus, lynx food supply gets smaller and the lynx population declines as well. 3.Finally, with fewer lynx preying on them, the hare population begins to recover and the cycle repeats.

Summary lynx & hare cycle more lynx  less hares  less lynx  more hares  more lynx  less hares…

Q1. What would happen when a new species introduced whether accidentally or deliberately into a new ecosystem? New species as new food source for native species Competition with native species occurs Q2. How do exotic species get into new ecosystem? Natural migration, air travel, fishing, import, waterway travel Q3. How alien species differs from invasive species? Alien species: accidentally or deliberately introduced into a new location; usually harmless to new ecosystem Invasive species: take over the habitat of native species

To be invasive A species must -adapt to the new area easily -reproduce quickly -harm property, the economy, or the native plants and animals of the region.

Invasive species case study: Zebra mussels in Lake Erie

Why zebra mussels problematic? -Grow on any hard surface -Cost industries billions of dollars to clean up - Cause decline in population of native species

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Graphing activity 2-2 TO BE HANDED IN DUE Follow Procedure #1-3 To add line of best fit: Right click mouse when cursor is place over graph; Add trendline Select Linear Answer Questions #1-3 and 5 (no 4)

If both of these species became endangered, which has a better chance of rebounding?