Chapter 2 Principles of Ecology You will learn: 1. What an ecologist does. 2. Some important aspects of an organism’s environment. 3.Trace the flow of energy and nutrients in the living and nonliving worlds

Why it’s important: To understand life. Know how organisms meet their needs. Reduce the impact of the human population. Understand how living things depend on their environment.

2.1 ORGANISMS AND THEIR ENVIRONMENT A. What is Ecology? The Scientific study of interactions among organisms and their environment 1. Ecological study reveals relationships among living and nonliving parts of the world – Techniques include the fields of mathematics, chemistry, physics, geology and many more. 2. Scientific research includes both descriptive and quantitative methods. ** Descriptive - fur, Carnivora long, canines teeth, fur, warm blooded, feed young milk. ** Quantitative - how many (International System of measuring; commonly known as SI

3. What are some of the things we can learn from scientific research? Think about what it would be like without water treatment plants, vaccinations, microwaves etc.. Technology has caused problems as well. For example; over irrigation, toxic waste etc..

II. Aspects of Ecological Study A. Living things can be found in the air, on land and both fresh and salt water. B. The Biosphere is the portion of Earth that supports life. C. Nonliving Environment. Abiotic factors - nonliving part of an organisms environment. (Name some) 1. What are some of the effects of Abiotic factors.?

D. The living Environment 1. Biotic factors - All the living organisms that inhabit an environment. (Name some) 2. How do living plants affect you? How do dogs affect you?

III. Levels of Organization in Ecology All organisms depend on others for food, shelter, protection and reproduction. Biosphere Ecosystem Communities Populations Organisms

A. Interactions within populations 1. Populations - a group of organisms of one species that interbreed and live in the same place at the same time. 2. Members compete - only if resources are in short supply. Members share.

B. Individuals interact within Communities No species lives independently of other species. 1. Community - a collection of interacting populations 2. A change in one population in a community will cause changes in other populations.

C. Interactions among living things and abiotic factors from ecosystems Ecosystems - The interaction among the populations in a community and the community’s abiotic factors. Three kinds of Ecosystems A. Terrestrial — land B. Aquatic - lakes and rivers C. Marine -oceans and seas

IV. Organisms in Ecosystems A habitat is the place where an organism lives. Habitats can both change and even disappear A. Niche - the role and position a species has in its environment. Each species is unique in satisfying all its needs. B. Living relationships Some species enhance their chances of survival by forming relationships with other species

Types of Living Relationships 1. Symbiosis - living together 2. Predator/prey - one species gets food the other is eaten. 3. Commensalism - one species benefits. The other is neither harmed nor benefitted. 4. Mutualism - two species living together both are beneficed. 5. Parasitism - One species is benefitted the other is harmed but is not usually killed .

2.2 Nutrition and Energy Flow I. How Organisms obtain energy Energy drives all events – walking, flowering and reproducing. The ultimate source of energy on Earth is the Sun.

A. The producers: Autotrophs. Organisms that use energy from the sun or energy stored in chemical compounds to make their own nutrients. Plants, some unicellular organisms are the most common.

B. the Consumers: Heterotrophs Organisms that obtain nutrients by eating other organisms. 1. Herbivores - eat plants 2. Carnivores - eat animals A. Scavengers - feed on carrion and refuse Why are scavengers important? 3. Omnivores - eat both plant and animal material. 4. Decomposers - fungi; breakdown dead and decaying material

II. Matter and Energy flow in Ecosystems A. Food Chains: Pathways for matter and energy Nutrients and energy proceed from Autotrophs to Heterotrophs and then to decomposes. Chains consist of 3 steps but most --no more than five. Why? B. Trophic Levels – represent links in the chain.

Each step in a chain represents a Trophic level. C. Food Webs - all the possible feeding relationships at each Trophic level in a community. D. Energy and Trophic levels: Ecological pyramids.

D. Energy and Trophic levels: Ecological Pyramids 1. Shows how energy flows through an ecosystem 2. Each Pyramid summarizes interactions of matter and energy at each Trophic Level.

3. The total energy transfer from one Trophic Level to the next is only about 10% 4. The energy lost enters the environment as heat. 5. A pyramid of numbers is based on population size.

Pyramid of Numbers

Pyramid of Energy

III. Cycles in Nature A. Water cycle The elements that make up the bodies of organisms alive today are the same atoms that have been on Earth since life began. A. Water cycle

B. Carbon Cycle

C. Nitrogen Cycle

D. Phosphorus Cycle