Ecology – Chapters

Populations Population – all the individuals of a species that live in one area at one time. Examples – all the red squirrels in Red Wing, all the oak trees in a forest, all the leeches in a lake

3 Key Factors of a Population Size – Number of individuals (ex. 5,167,101 people live in MN) Density – Number of individuals in a given area (ex. Twin Cities area is densely populated) Dispersion – Way individuals are arraigned

Population Growth Rate Exponential Growth – curve resulting from steady population growth Carrying capacity – maximum number or individuals an environment can support

What determines the carrying capacity? Predators Disease Availability of Resources –Food –Water –Space

Fluctuations in population size

Populations change due to relationships between species

Coevolution Coevolution – long term, interdependent changes take place in two species as a result of their interaction.

Ecology Ecology is the study of interactions between living organisms with one another and their physical (nonliving) environment. Habitat – place where a species lives. Ecosystem – All the living things that live in an area and its physical environment.

Abiotic Factors Non-living components of an ecosystem. Examples –Sunlight, air, soil, nutrients, water, temperature

Biotic Factors Living components of ecosystem Bacteria, Protists, Fungi, Plants, Animals

Succession Ecosystems change over time. Two types of succession. –Primary - occurs where life has never occurred before. (ex. Volcanic rock, glacier clearings) –Secondary – occurs where there has been previous growth. (ex. Abandoned farms, forest clearings)

Primary Succession

Secondary Succession

Aquatic Succession

Energy Flow through Ecosystems Producers – Capture and convert sun’s energy into chemical energy Consumers – Eat / consume plants and other organisms to obtain energy Decomposers – breakdown / recycle nutrients back into environment Trophic levels – show organism’s source of energy. Energy moves from one level to another

Producers

Consumers

Decomposers

Trophic Levels

Classes of Consumers Herbivore – Eats plants (Primary Consumer) ex – cow, deer, some ducks Carnivores - Eats other consumers ex – lion, killer whale, snakes, wolves Omnivore – Eats both plants and animals ex. Bears, humans, raccoons Detritivores – Obtain energy from organic wastes or dead organisms. Ex. Worms, bacteria

Forest Food Web

Aquatic Food Web

Biogeochemcial Cycles Biogeochemical cycles – pathways which form when a substance enters a living thing then exits back to the physical environment. Examples include: –Water Cycle –Carbon Cycle –Oxygen –Nitrogen

Water Cycle

Carbon Cycle

Oxygen Cycle

Nitrogen Cycle

Interactions Among Organisms Parasitism – one organism feeds on or lives on another organism (host).

Interactions among Organisms Predation – one organism feeds off another

Interactions among Organisms Mutualism – both species benefit from interaction.

Interactions among Organisms Commensalism – relationship where one species benefits and the other is unaffected

Niche Niche – the role an organism plays in an ecosystem. Examples – diet, reproduction time, and time of activity. 2 organisms both live in the same area, but do not compete due to different requirements

Biomes Biome is a biological community which occurs over a large area of land. Biomes are influenced by the climate of the area. Difference between climate and weather? 2 Climate factors which have greatest influence on the biome are Temperature and Precipitation.

Biomes of the World Named for the dominate vegetation of the area

TUNDRA

TIAGA (Coniferous Forest)

TIAGA

Deciduous Forest

Tropical Rainforest

GRASSLAND

DESERT

Aquatic Ecosystems Freshwater – Lakes, ponds, streams, and rivers. Marine – Oceans and Seas (almost 75% of the Earth’s surface) Wetlands – Swamps, marshes, & bogs Estuaries – transition zone between freshwater river and ocean. Very productive due to high nutrients coming from freshwater river.

Aquatic Ecosystem

Estuary

Changing Environment Acid Rain – Coal plants emit smoke high in sulfur. Sulfuric acid results and this acidic solution falls back to the surface. Causes lakes, forests, & buildings to be damaged, especially areas downwind from the industrialized area.

Changing Environment Ozone Layer – Ozone or O 3 shields our planet from the sun’s UV rays. CFC’s (chemicals used as coolants and propellants) destroy Ozone molecules. Exposure to UV radiation results in skin cancer, cataracts, and eye cancer. Many countries limit or ban CFCs. Problem is that CFCs remain active destroying Ozone molecules for many years.

Changing Environment Climate change – Since the 1950s the average global temperature has steadily increased. Greenhouse effect – Our planet is surrounded by an insulating layer of gas which makes life possible on Earth. Much like the glass in a greenhouse, the gases let the sun’s radiant energy in and traps the heat inside. Greenhouses gases - water vapor, methane, carbon dioxide, and nitrous oxide.

Changing Environment As the average temperature has increased so has the level of carbon dioxide.

CO 2 levels fluctuate by season due to winter vs summer photosynthesis levels in the Northern hemisphere.

Annual Mean Temperature Anomalies

Annual Precipitation Trends

Changing Environment Effects of climate change: source EPA –Loss of habitat for living things –Loss of biodiversity –Sea level rise (.6 to 2 feet in next century) –Change in temperature and precipitation patterns will affect world food supply –Change in forests –Change in availability of usable water

Changing Environment What can be done to combat climate change. –Use less energy (efficient light bulbs, insulate your home, fuel efficient cars) –Reduce, Reuse, Recycle –Don’t waste water –Renewable energy

Environmental Issues Loss of Resources – we are using topsoil, ground water, and some species of living things at a rate faster than it can be replaced. Human Population Growth – rapid growth places stress on already limited resources. Pollution / Run-off –Biomagnification –Algal Blooms

Biomagnification

Solving Environmental Problems Conserve Energy Reduce, Reuse, Recycle Do not waste our planet's resources Compost Educate yourself and others about issues that affect your area and the world Contact lawmakers about their environmental policy