II. Connections
a. Both biotic potential and carrying capacity refer to the limits of a certain population within its own ecosystem. Biotic potential is the maximum rate of increase per individual for any population growing under ideal conditions, while carrying capacity is the maximum number of individuals in a species or population that a given environment can sustain indefinitely.
b. A trophic level is all organisms the same number of transfer steps away from the energy input into an ecosystem. Biological magnification relates to trophic levels because it is a process in which a substance that degrades slowly or not at all becomes ever more concentrated in tissues of organisms at higher trophic levels of a food web.
c. Both autotrophs and detritovores play crucial roles in the flow of matter through the biosphere (including water, carbon and nitrogen). Autotrophs are the primary producers of energy in the energy pyramid , while detitivores decompose some organisms and are responsible for returning water , carbon, and nitrogen back into the soil which then returns to the atmosphere.
d. Mitochondria are the organelles in which the second and third stages of aerobic resp. take place. With an increase of human population, as well as other factors such as cars and industrial factories, green house gases can be created by the increase of carbon in the atmosphere, resulting in global warming.
III. Essentials
a. I. Density-dependent limiting factors
A. Populations cannot keep growing due to lack of resources
a. Essential source in short supply is a limiting factor on pop. Growth
b. Often more than 1 factor that limits growth
II. carrying capacity and logistic growth
A. Populations require more resources as they grow
a. Carrying capacity is max # of individuals in a pop. That can sustain in environment
b. Once limit is passed, pop. Will go down until balance
B. Logistic growth
a. Shows what affects carrying capacity has on growth
b. Density dependent controls help reduce the odds for individual survival
III. Density independent limiting factors
A. Cause less births andmore deaths regardless of pop. Density
a. Ex. Monarch butterflies in central mexico threatened by deforestation and freezes
b. Type I curves reflect high survorship until fairly late in life, then high mortality rates, such as in elephants. Type II curves reflect a fairly constant death rate at all ages, which is seen in snowy egret populations. Type III curves signify a death rate that is highest early in life, exemplified in sea star larvae populations.
c. 1. An age structure diagram depicting negative growth would have bars representing reproductive and post reproductive ages much larger than pre-reproductive ages. 2. An age structure diagram depicting no growth would show all bars representing all ages generally at the same size. 3. An age structure diagram depicting rapid growth would have the pre-reproductive year bars substantially larger than the reproductive years, which would be greatly larger than post-reproductive years. 4. An age structure diagram depicting slow growth would, like a rapid growth diagram, have the younger ages bigger than older ages, just not as drastic.
d. I. Inputs into ecosystems
A. Nitrogen mainly enters via nitrogen fixation
a. moves up trophic levels
b. ammonification transfers ammonium into soil
c. nitrification helps the ammonium become nitrogen
B. Loss of nitrogen via denitrification
a. other factors of loss include runoff and leaching
II. disruptions by human activities
A. Deforestation and grassland conversion
a. Erosion
B. Rotation of crops
a. Helps counter nitrogen losses
C. Fertilizers
a. Pollutes bodies of water with nitrogen waste
b. Does promote algal blooms
(for diagram see pg. 860)
Nitrifying bacteria are located on the cycle when nitrification occurs, denitrifying bacteria are located where denitrification occurs on the cycle, ammonifying bacteria are located where ammonification occurs, and nitrogen-fixing bacteria are located where nitrogen-fixing occurs.
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