How do we describe an Ecological Population? Evolutionary Genetic Description of a Population - gene frequencies, {P A, P a } - genotype frequencies, {G AA, G Aa, G aa } Ecological Population Description has 3 parts: - 1) Distribution: What is the Geographic area where the species occurs? - 2) Density: What is the Number of individuals per unit area. - 3) Dispersion: What is the Local Distribution of individuals within a specific, small region.

Population: individuals of the same species present in the same place at the same time. Community: the assemblage of populations of different species present in the same place at the same time. Ecosystem: the community of species present plus the abiotic environment (climate) with which they interact.

What is the Science of Ecology? Ecology is the study of geographic distribution and abundance of organisms that result from interactions between organisms and their environment. (Where and How Many are affected by interactions.) Environment: an organism’s surroundings - abiotic environment – physical environment, like temperature, moisture, or day length. - biotic environment – other living species.

Ecology is a basic science, concerned with the geographic distribution, number, and interactions among organisms. Environmental Science is an applied science, based on applying ecological principles to solve specific problems, like reforestation or detoxification or recycling organic waste. Ecology is to Environmental Science much like Physics is to Engineering. Environmentalism is a political movement.

Other Applications of Ecology Ecology Environmental Science Conservation Natural History Agriculture, Forestry & Resource Management Food Science Human Demography Epidemiology of Human Disease Public Health Science

What Ecologists Do: 1. Make observations. 2. Formulate hypotheses. 3. Test hypotheses using laboratory and field experiments and statistical tests of data. 4. Use theory to test hypotheses and make predictions. Mathematical Models: simplified descriptions of organisms, their properties, and their populations, which are used to explore the dynamics of populations.

Example of a Model in Ecology: Dynamics of HIV Goal: understand the rate of transmission of the virus Number of Uninfected People Number of Infected People With virus Number of People With virus And AIDS Simple models reveal that this blood borne virus would go extinct, if there were fewer contacts between infected and uninfected people. Rate of spread depends upon: sexual contacts, injected or intravenous drug use, blood transfusions, birth rate, etc.

Three Basic Questions in Population Ecology: What determines the geographic distribution of a species? What determines the abundance of individuals in a local population? What maintains diversity of species within a community?

Black-capped Chickadee This seed-eating bird is found in North America in the Blue Region. What determines the distribution of this species?

European Starling Introduced into US from England by Shakespeare enthusiasts in What determines the distribution of this species?

What about our National Bird? Nearly exterminated from continental US. Suffered from DDT poisoning. DDT banned and the eagle was saved by the Endangered Species Act. Reintroduced into Indiana in 1985: Indiana DNR released 73 young eagles between 1985 and 1989

Bald Eagles were driven extinct in Indiana due to habitat loss and DDT poisoning. DDT was the first chemical insecticide. -- Developed during World War II. -- Bio-accumulated in top predators and caused egg shells of birds of prey to thin and eggs did not hatch. -- Motivation for Endangered Species Act. -- DDT was banned. -- Saved the eagle and falcon in the continental US.

Bald Eagles were driven extinct in Indiana due to DDT poisoning. In 1985, they started reintroducing Eagles to Indiana. Between 1985 and 1989, the Indiana DNR Released 73 eagles.

Locations of Bald Eagles in January of total counted from a helicopter - 31 nests - 13 nests at Lake Monroe!!

Table 1: Bald Eagle Nesting in Indiana Nest Territories Nest Success Young Fledged Nesting Attempts

Clumped dispersion is when individuals aggregate in patches. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 52.2a

Uniform dispersion is when individuals are evenly spaced. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 52.2b

Random dispersion: the position of each individual is independent of the others. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 52.2c

Locations of Bald Eagles in January of 2001 Eagle sightings across Indiana are a. clumped b. uniform c. random

Locations of Bald Eagles in January of 2001 Eagle sightings across Indiana are a. clumped b. uniform c. random

Eagle nests at Lake Monroe are a. clumped b. uniform c. random

Three Basic Questions in Population Ecology: What determines the geographic distribution of a species? What determines the abundance of individuals in a population? What maintains diversity of species within a community?

Fig Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings What determines the abundance of individuals in populations? (whooping cranes)

Number of Nesting Pairs of Eagles in Indiana 73 Eagles introduced Between

Number of Caribou Why did the reindeer population increase quickly and then crash? Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Why do some populations increase smoothly and level off and others fluctuate in numbers? overshoot Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Increase/decrease in Lynx numbers lags (follows) increase/decrease in Snowshoe hare numbers.

Bald eagle numbers on Indiana Midwinter Bald Eagle Surveys, John Castrale and Amy Ferchak, DNR Biologists

Three Basic Questions in Population Ecology: What determines the distribution of species? What determines the abundance of individuals in populations? What maintains diversity of species within a community?