Ecology: Chapter 18 Ecology is the study of the interactions between organisms and their environment: -biotic: living components -abiotic: nonliving components -This quality is called interdependence.

Levels of Organization Biosphere contains the combined portions of the planet in which all life exists, including, land, water, and air. It extends from about 5 miles above the Earth’s surface to the deepest parts of the ocean The biosphere contains smaller ecosystems: a collection of all the organisms that live in a particular place, together with the nonliving environment

Levels of Organization Communities are groups of different populations that live together in a defined area. It may contain a few or a thousand species interacting together. Only contains biotic factors Populations are groups of individuals that belong to a single species AND live in the same area Species is a group of organisms so similar to one another that they can breed and produce fertile offspring

Energy Flow Make a food web on your paper showing the relationships and flow of energy between the following organisms: cherry tree, earthworm, robin, butterfly, frog, rabbit, squirrel, fox, snake, and eagle Hints: Producer: tree Herbivores: earthworm, butterfly, rabbit, squirrel Omnivores: robin Carnivores: frog, fox, snake, eagle

Does your Flow of Energy look like this? Identify the producers (P), Primary consumers (1°C), Secondary consumers (2°C), Tertiary consumers (3°C), and Quaternary (4°C) In addition: Detritivores: feed on waste or detritus (including dead organisms, fallen leaves and animal wastes. Decomposers: many bacteria and fungi cause decay by breaking down complex materials into simpler molecules. They return the nutrients to the environment.

More on Energy Flow When an organism eats another, molecules are broken down and energy is transferred An organism’s trophic level, indicates its position in the sequence of energy levels. Most ecosystems have only 3-4 trophic levels Why only 3-4 trophic levels? Rule of 10

More on Producers Chemosynthesis: some autotrophic bacteria do not use sunlight to make their own food. They use chemicals not containing carbon (inorganic) Photosynthesis: most organisms use this process to make their own food 6CO2 + 6 H2O + sunlight –> C6H12O6 + 6O2

More on Producers Gross Primary Productivity: the rate that producers are able to make organic compounds Biomass: The organic material that has been produced in an ecosystem. Producers make biomass Net Primary Productivity…the rate biomass accumulates NPP = GPP – producer respiration rate

How Do Organisms Handle A Changing Environment? An organism can survive and function in conditions outside its optimal range, but its performance is reduced. Acclimation: how some organisms adjust their tolerance to abiotic factors (NOT the same as adaptation) When environments fluctuate: Conformers: change with environmental conditions Regulators: use energy to control some of their internal conditions Escape from Unsuitable Conditions Hide in the shade during hot part of the day Dormancy: enter a state of reduced activity Migration: move to favorable habitat

The NICHE Niche: the range of conditions a species can tolerate, the resources it uses (and how it obtains resources), the number of offspring, its time of reproduction, Other interactions with its environment Generalists: broad niche; can handle a large range of conditions Specialists: narrow niche

Biogeochemical Cycles

Biogeochemical Cycles THE CARBON CYCLE

Biogeochemical Cycles The NITROGEN CYCLE provides Nitrogen for proteins and nucleic acids Nitrogen gas makes up 78% of the atmosphere, Plants can only use nitrogen in the form of nitrate. Converting Nitrogen gas to nitrate is called nitrogen fixation. Nitrogen fixing bacteria: transform nitrogen into a usable form. Words to know from your text: ammonification, nitrification, denitrification

Biogeochemical Cycles The PHOSPHORUS CYCLE: the essential material for bones, teeth, DNA and RNA When rocks erode, small amounts of phosphorus dissolve as phosphate (and from fertilizer and decomposing organisms) Plants absorb phosphorus Animals eat plants, ETC.