Ecology! The easy stuff 

Populations Population: all individuals of 1 species in area Population size : number of individuals Population density : number per area Population distribution : dispersal pattern

Distribution patterns 1) Clumped: most common, a) group around resources b) social behavior c) lack of offspring dispersal 2) Uniform (or close enough) a) territory division 3) Random – rare a) uniform resources b) ignore each other

Population Size Estimates 1) full count 2) Quadrats 3) Transects 4) Mark-recapture m-r good for organisms that move around a lot

Mark-recapture Based on assumption: % marked on day 2 same as the % of the total population that is marked Steps: day 1 capture organisms & mark them day 2 capture organisms & see what % are marked calculation day 2 marked = day 1 marked day 2 total total population

Population Growth Positive growth …….. birth & immigration Negative growth …… death & emigration Migration : periodic change w/ seasons Zero population growth (ZPG) : deaths = births Per capita = per individual Net reproduction = births – deaths Doubling time: time for pop to double size

Rapid Population Growth Exponential growth : population grows at a rate proportional to its size a) ideal conditions allow max growth rate Biotic potential : max growth rate for a population (under ideal conditions)

Logistic Population Growth Exponential Growth slowed by 1) Density dependent limiting factors predation, parasites, disease limited resources, competition 2) Density independent limiting factors weather, natural disasters, humans

The current estimate of the wolf population in Michigan’s Upper Peninsula is 658. The number of wolves has been on a steady uptick since 1989, when there were a mere three wolves The state selected three zones where it said nonlethal and targeted lethal control measures were unable to reduce complaints filed by residents of wolves attacking livestock and pets, and appearing too close to neighborhoods.

If folks in Detroit want to vote to protect the wolves, we’ll send them down below the bridge to them,” said a man getting his hair cut in a barbershop downtown, who asked that his name not be used. Lifelong Ironwood resident Al Clemens said the wolves have “decimated” the local deer population, affecting the popular — and economically important — local deer hunt. In recent years, hunters at his deer camp south of town have seen only about one-sixth of the deer they used to see, he said

We had wolves there; they weren’t afraid of you,” he said We had wolves there; they weren’t afraid of you,” he said. “You could walk into camp and see a wolf maybe 35-40 yards away. He didn’t run or anything, just walked off.”

The DNR has killed 89 wolves since 2003 — 62 related to a livestock concern; 27 to a human safety concern. Bump said the agency will not stop using lethal and nonlethal means to deal with problematic wolves in a timely manner.

Some want to hunt wolves because they believe wolves threaten human safety. On the extremely rare occasions when wolves do pose such a threat the concern needs to be addressed immediately and targeted precisely at the offending wolf. A general wolf hunt is not a sensible approach for dealing with this concern.

Some want to hunt wolves because they kill livestock Some want to hunt wolves because they kill livestock. Wolves killed just 11 head of cattle per year, on average, between 2001 and 2010. Less than 10% of the wolf population is involved with livestock losses. We should be concerned with livestock losses, and there are good means for dealing with those losses, including adequate husbandry of livestock, financial compensation for losses, and a Michigan law allowing one to kill wolves attempting to kill or injure their livestock or dog. A general wolf hunt is not a sensible approach for dealing with this concern.

Some want to hunt wolves because they kill deer Some want to hunt wolves because they kill deer. Michigan’s Upper Peninsula is home to about a quarter million deer. Wolves kill approximately 23,000 deer each year. Malnutrition kills more than twice that number during a typical winter. Hunters kill more than twice what wolves kill in a typical hunting season. If there were every a wasteful way to kill deer it is with our automobiles. We kill about 10,000 deer each year with our automobiles

Carrying capacity = Max # individuals an area can support indefinitely (D) Steady state #2 on graph Life history patterns: adaptations that influence survival, reproduction & population size

Life History Patterns r-selected a) favor low pop density (d independent) b) quick production of many small babies c) high biotic potential so called r-selected K-selected a) favor high pop density (d dependent) b) good competitors c) low biotic potential & parental care

Life History Strategies

Different Life Histories = Different Survivorship Curves Type I : live long & prosper (parental care) k-selected Type II : could die at any time… good luck Type III : high infant mortality r-selected

Human Population growth growth to 2 billion…………..123 years Growth to 3 billion …………. 33 years Growth to 4, 5, 6 ………….. 14, 13, 12

Fertility Rates and $$$$$$$ Total Fertility Rate (TFR) – average # children born per woman World wide TFR = 6.5 Replacement = 2.1 TFR in developed countries = at or below 2.1 TFR in developing countries = highest

Demographic Transition Model

Age Structure Diagrams 3 categories of individuals: -pre-reproductive (base of diagram) -reproductive (center of diagram) -post-reproductive (top of diagram) Fast growth = wide pyramid shape Slow growth = narrow pyramid shape ZPG = straight at bottom, narrow pyramid at top Negative growth = bottom & top more narrow than center