Study of relationships between organisms and their environments. Ecology Study of relationships between organisms and their environments.

Ecosystem Organization Biosphere Biome Ecosystems Communities Populations Organisms

Organism A single living thing

Habitat (house) Niche (occupation) The place where an organism lives out its life Niche (occupation) Strategies and adaptations a species uses in its own environment How the species gets food and shelter

Population A group of organisms that belongs to the same species Population members breed with each other and live in the same area

Population dynamics The study of the change in population numbers and the factors influencing those changes Population size Birth Immigration Death Emmigration

Models of Population Growth Exponential Growth Birth exceeds death Population Size Explodes T=time in generations r-= growth rate N=popsize R=<>1

Exponential growth – density independent Population size Time, in generations

Can this happen in nature? Yes Invasive species Uniform habitat No predators No disease Unlimited area Can this happen? 70 miles a year No constraints

K Logistic equation – density dependent Population size Carrying capacity r = intrinsic rate of increase. B-D. R=1+r Time, in generations

K = Carrying capacity The maximum number of individuals that a habitat can support for a prolonged period of time Not constant, it fluctuates. How to reconcile with density independence

Limiting Factors-factors that affect the carrying capacity Density-independent factors Weather (storms, cold, drought) Some diseases (DDT poisoning) Density-dependent factors Food or Predators Space or Shelter Other diseases (rabies)

Population structure A population that is 75% adults, 25% juveniles is very different from a population of 25% adults and 75% juveniles.

Population structure Age structure – distribution of ages in a population. Size structure – distribution of sizes in a population.

Community Different populations in a certain area at a certain time. Changes in one population cause changes in other populations

Symbiosis living together Three major kinds of symbiosis Mutualism-both species benefit Commensalism-one species benefits and the other is neither helped nor harmed Parasitism-one species benefits at the expense of another Predator-Prey Relationship

Ecosystem All the different populations in a community and the community’s abiotic factors There are two major kinds of ecosystems: terrestrial and aquatic

Biotic vs. Abiotic Biotic factors – all living organisms in an environment Abiotic Factors—nonliving factors in an environment Air Temperature Water Light Soil

Biomes The typical weather patterns over a long period of time is the climate.

Biomes are a group of ecosystems with similar climates (temperature and rainfall) and organisms.

Temperatures and Precipitation Determine the type of Biome

Is the temperature of each Biome: Hot, moderate, or cold? Tundra - Desert - Temperate Grassland - Tropical savanna - Taiga - Temperate forest - Tropical rainforest - Tundra - Cold Desert - Hot Temperate Grassland - Moderate Tropical savanna - Hot Taiga - Cold Temperate forest - Moderate Tropical rainforest - Hot

Tundra

Tundra Found in Antarctica and the North Pole, North of the Arctic Circle. Grass, lichen and herbs Permafrost – layer of soil that is always frozen. Very short warm season that is very wet Many insects during warm season

Plants include mosses, shrubs and willow trees.

Animals such as wolves, foxes, hares and caribou grow thick fur during the winter to keep warm.

Taiga Found in Northern Hemisphere. Spruce and Fir trees Growing season very short Nearly constant daylight in summer Many lakes and swamps

Temperate Forest

Temperate Forest climate and amount of sunlight can vary tremendously between each season. four types: Deciduous forest, Evergreen forest, temperate rain forest, and mixed evergreen and deciduous forests.

Animals include deer, skunks, insects and bears.

Grasslands Tall, perennial grasses and no trees. Cover a quarter of the land on Earth.

Savannas are like the grasslands except that they do receive enough rain to support small trees.

Savanna Found near equator between tropical rain forest and desert biomes Grass, scattered trees, shrubs, many with thorns Many grazing animals Have a wet and dry season Plants and animals most active during wet season.

Animals that appear in both include: bison, antelopes, giraffes and kangaroos.

Desert Deserts take up 8.6 million square miles on Earth.

Desert Get less than 25 cm of rain each year Has little or no vegetation Driest places on earth

In the Desert Biome, plants (cactus) have the ability to hold water for later use and most animals (scorpion) are nocturnal.

Rainforest

Rainforest Found near the equator Over half of the world's plant and animal species live here. All fit into only seven percent of the world's land.

Rain Forests have many types of plants and animals

COFFEE BEANS

Biosphere Portion of Earth that supports life