Lecture 01 Ecology Ecology as a Science

What is ecology? Characteristics of living things Levels of organization of living things Levels of organization of ecosystems Basic relationships within ecosystems – terminology Scientific logic – how we know (what we think) we know

Living things are organized as organisms: Atoms  compounds  cells  tissues  organs and organ systems  organisms All living things composed of cells Not all organisms show all these levels of organization!

Populations – single organisms – basic unit in ecology - fill a niche (‘job’ or function) communities - populations of many types of organisms ecosystems: All organisms living in an area, and the physical environment (habitat) with which these organisms interact.

"When we try to pick out anything by itself, we find it hitched to everything in the universe.“ John Muir

Populations All the members of one species that live in the same area make up a population.

Community

A community, together with its non-living environment is referred to as an "ecosystem". PondTundra

Largest Ecosystem is the Biosphere

Ecology vs. Environmentalism Environmentalist: Save the world! –An emotion, a cause Ecologist: Understand the world! –How does it work – uses scientific method –Poses specific questions in the form of hypothesis –Involves controlled experiments and detailed study

Observation: Hydrangeas of the same variety but growing in different parts of the garden have different colors. Hypothesis: Something about the soil is different; perhaps acidity (pH).

Set up experiment to test hypothesis: –Grow one group of Hydrangeas in acid pH –Grow second group of hydrangeas in soil with basic pH –Keep everything else the same –Observe:  Acid pH Alkaline pH 

Scientific Theory Hypotheses are tentative explanations –phenomenon in a particular situation Theories are widely accepted explanations –Support from many lines of evidence –Basis of understanding –May be revised or modified –Theory of Evolution

14 Warbler Feeding Zones

Organisms Require Resources Energy flows through ecosystems –Trophic levels = ‘feeding’ levels –Some energy is lost during transfer to each higher trophic level

Materials cycle –Carbon, phosphorus, nitrogen, water cycle through biotic and abiotic aspects of ecosystems –Global in scale Biotic cycling

Biotic and Abiotic

Nutrients Cycle Include things like carbon, nitrogen, phosphorus –Some required in greater concentrations than others –Excesses may be toxic

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Birds of prey Birds Mammals Arthropods Fish Algae Mollusks Annelids Meiofauna Bacteria and fungi Inorganic nutrients Humans Top carnivores Carnivores Herbivores Photosynthesizers Decomposers Inorganic nutrients Inorganic nutrients

Summary Ecology is an investigative science that relies on the scientific method The scientific method requires observation, creation of a hypothesis, and data collection to refute or support the hypothesis. Ecology and evolution are two separate disciplines that overlap in their investigation of the natural world. An understanding of ecology may lead us to sound environmental decisions