Ecology of Populations

Scope of Ecology Ecology - Study of the interactions of organisms with other organisms and the physical environment. Habitat - Place where an organism lives. Population - All the organisms within an area belonging to the same species. Community - All various populations interacting at same locale. Ecosystem - Community of populations.

Ecological Levels

Density and Distribution of Populations Population Density - Number of individuals per unit area or volume. Population Distribution - Pattern of dispersal of individuals within the area of interest.

Population Growth Models Exponential Growth Number of individuals added each generation increases as the total number of females increases. Biotic Potential - Maximum population growth that can possibly occur under ideal circumstances. Environmental Resistance - All environmental conditions that prevent populations from achieving biotic potential.

Logistic Growth

Carrying Capacity Carrying Capacity is the maximum number of individuals of a given species the environment can support. The closer the population to the carrying capacity, the greater the environmental resistance. Biotic potential is having full effect and birthrate is a maximum during exponential growth.

Regulation of Population Size Density - Dependent Factors Number of organisms present influences the effect of the factor. Competition Predation Density - Independent Factors Number of organisms present does not influence the effect of the factor. Natural Disasters

Life History Patterns r - Strategists (Opportunistic) Produce large numbers of offspring. Small body size. Early maturity No parental care. Density independent controls. Good dispersers and colonizers.

Life History Patterns k - Strategists (Equilibrium) Produce small numbers of offspring. Large body size. Late maturity Significant parental care. Density dependent controls. Specialists

Environmental Impact Environmental impact of a population is measured in terms of: Population Size Resource Consumption Per Capita Resultant Pollution

Community Ecology

Community Concept A community is an assemblage of populations interacting with one another within the same environment. Composition is a listing of various species in the community. Diversity includes both species richness and species diversity.

Habitat and Ecological Niche Habitat is the area an organism lives and reproduces in. Ecological niche is the role an organism plays in its community, including its habitat and its interactions with other organisms. Fundamental niche - All conditions under which the organism can survive. Realized niche - Set of conditions under which it exists in nature.

Predator-Prey Interactions Predation occurs when one living organism, the predator, feeds on another, the prey. Presence of predators can decrease prey densities, and vice-versa.

Prey Defenses Prey defenses are mechanisms that thwart the possibility of being eaten by a predator. Spines Tough Epidermis Poisonous Chemicals Camouflage Bright Coloration Flocking Behavior

Symbiotic Relationships Symbiosis refers to interactions in which there is a close relationship between members of two populations. Parasitism Parasite derives nourishment from a host, and may use host as habitat and mode of transmission. Endoparasites Ectoparasites

Symbiotic Relationships Symbiosis refers to interactions in which there is a close relationship between members of two populations. Parasitism Parasite derives nourishment from a host, and may use host as habitat and mode of transmission. Endoparasites Ectoparasites

Commensalism Commensalism is a symbiotic relationship in which one species is benefited and the other is neither benefited nor harmed. Ex: Remoras and Sharks Many examples may turn out to be mutualism or parasitism. Amount of harm or benefit two species do to one another is partially determined by the investigator.

Mutualism Mutualism is a symbiotic relationship in which both members of the association benefit. Often help organisms obtain food or avoid predation. Bacteria in human intestinal tact. Need not be equally beneficial to both species.

Predation, Competition, and Biodiversity In certain communities, predation by a particular species reduces competition and increases diversity. Predators that regulate competition and maintain community diversity are referred to as keystone predators. Introduction of exotic species into a new area may lead to unbridled competition and resultant reduction in biodiversity.

Ecosystems

Nature of Ecosystems Biosphere is part of the atmosphere, hydrosphere, and lithosphere that contains living organisms. An ecosystem where organisms interact. Ecosystems characterized by: One-Way flow of energy. Cycle of materials from abiotic environment through biotic community.

Energy Balances

Ecological Pyramids A trophic level is composed of all the organisms that feed at a particular link in a food chain. In general, only about 10% of the energy of one trophic level is available to the next trophic level. Explains why few carnivores can be supported in a food web.

Hydrologic Cycle

Carbon Cycle

The Nitrogen Cycle

Phosphorus Cycle

Sources of Water Pollution

The Biosphere

Biome Distribution

Climate and Biomes

Zones of a Lake

Conservation Biology

Conservation Biology and Biodiversity Conservation biology studies all aspects of biodiversity with the goal of conserving natural resources for this generation and future generations. Primary goal is the management of biodiversity for sustainable use by humans.

Value of Biodiversity Direct Value Medicinal Value Agricultural Value Crops Biological Pest Controls Pollinators Consumptive Use Value Wood Skins

Causes of Extinction Habitat Loss Occurred in all ecosystems, but recent concern focused on tropical rain forests and coral reefs. Habitat Fragmentation

Pollution Pollution can be defined as any environmental change that adversely affects the lives and health of living things. Acid Deposition Eutrophication Ozone Depletion Organic Chemicals Global Warming

Sources: Mader: Biology 8th Ed. Raven & Johnson: Biology 8th Ed.

This project is funded by a grant awarded under the President’s Community Based Job Training Grant as implemented by the U.S. Department of Labor’s Employment and Training Administration (CB-15-162-06-60). NCC is an equal opportunity employer and does not discriminate on the following basis: against any individual in the United States, on the basis of race, color, religion, sex, national origin, age disability, political affiliation or belief; and against any beneficiary of programs financially assisted under Title I of the Workforce Investment Act of 1998 (WIA), on the basis of the beneficiary’s citizenship/status as a lawfully admitted immigrant authorized to work in the United States, or his or her participation in any WIA Title I-financially assisted program or activity. Mader: Biology 8th Ed.

Disclaimer This workforce solution was funded by a grant awarded under the President’s Community-Based Job Training Grants as implemented by the U.S. Department of Labor’s Employment and Training Administration.  The solution was created by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor.  The Department of Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such information, including any information on linked sites and including, but not limited to, accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability, or ownership.  This solution is copyrighted by the institution that created it.  Internal use by an organization and/or personal use by an individual for non-commercial purposes is permissible.  All other uses require the prior authorization of the copyright owner. Mader: Biology 8th Ed.