Introduction to Ecology Chapter 18 Table of Contents Section 1 Introduction to Ecology Section 2 Ecology of Organisms Section 3 Energy Transfer Section 4 Ecosystem Recycling

Section 1 Introduction to Ecology Chapter 18 Objectives  Describe what the study of ecology entails.  Identify the importance of models to ecology.  State the five different levels of organization at which ecology can be studied.

Ecology Organisms and Their Environments  Species interact with both other species and their nonliving environment.

Section 1 Introduction to Ecology Chapter 18 Interdependence: A Key Theme in Ecology Interdependence is a theme in ecology—one change can affect all species in an ecosystem.

Section 1 Introduction to Ecology Chapter 18 Ecological Models  Ecological models help to explain the environment.

Chapter 18 Making an Ecosystem Model Section 1 Introduction to Ecology

Chapter 18 Levels of Organization  Ecologists recognize a hierarchy of organization in the environment: biosphere, ecosystem, community, population, and organism.

Chapter 18 Levels of Organization Section 1 Introduction to Ecology

Chapter 18 Levels of Organization, continued  The Biosphere  The broadest, most inclusive level of organization is the biosphere, the volume of Earth and its atmosphere that supports life.  From 8-10km above Earth’s surface to the deepest part of the oceans.

Section 1 Introduction to Ecology Chapter 18 Levels of Organization, continued  Ecosystems  The biosphere is composed of smaller units called ecosystems.  An ecosystem includes all of the organisms and the nonliving environment found in a particular place. pond

Chapter 18 Ecosystem Section 1 Introduction to Ecology

Chapter 18 Levels of Organization, continued  Communities, Populations, and Organisms  A community is all the interacting organisms living in an area.  Below the community level of organization is the population level, where the focus is on the individual organisms of a single species.

Chapter 18 Community Section 1 Introduction to Ecology

Section 2 Ecology of Organisms Chapter 18 Objectives  Compare abiotic factors with biotic factors, and list two examples of each.  Describe two mechanisms that allow organisms to survive in a changing environment.  Explain the concept of the niche.

Section 2 Ecology of Organisms Chapter 18 Ecosystem Components  Biotic and Abiotic Factors  Both biotic, or living, factors and abiotic, or nonliving, factors influence organisms.  Examples Biotic factors: other organisms Abiotic factors: climate, sunlight, and pH. Biotic and Abiotic Factors

Section 2 Ecology of Organisms Chapter 18 Organisms in a Changing Environment  Each organism is able to survive within a limited range of environmental conditions.  Example: temperature

Organisms in a Changing Environment  Tolerance Curve: performance versus values of an environmental variable.

Organisms in a Changing Environment  Tolerance  Organisms can not survive in conditions that fall outside their tolerance zone.  Organisms can survive and function in conditions outside the optimal range but performance will be reduced.

Organisms in a Changing Environment  Acclimation  Some organisms can adjust their tolerance to abiotic factors through the process of acclimation. Goldfish raised at difference temperaturs have different tolerance curves.

Section 2 Ecology of Organisms Chapter 18 Organisms in a Changing Environment  Control of Internal Conditions  Conformers are organisms that do not regulate their internal conditions; they change as their external environment changes. (Reptiles)  Regulators use energy to control some of their internal conditions. (Humans) seaman.com/Reptiles/Usa/Nevada/ValleyOfFire/HornedLizardCrouching.jpg perspective/people-out-persp.gif

Section 2 Ecology of Organisms Chapter 18 Organisms in a Changing Environment  Escape from Unsuitable Conditions  Some species survive unfavorable environmental conditions by becoming dormant or by migrating. Example: desert species which are active during cooler night and hide underground during the hot day. Dormancy: long-term strategy to enter a reduced state of activity Migration: moving to a more favorable habitat

Section 2 Ecology of Organisms Chapter 18 The Niche  A niche (nichier, “to nest”) is a way of life, or a role in an ecosystem.  Generalists: broad niches (Raccoons)  Specialists: narrow niches (Koala) Niche

Chapter 18 Earthworm Niche Section 2 Ecology Of Organisms

Section 3 Energy Transfer Chapter 18 Objectives  Identify several kinds of producers and consumers in an ecosystem.  Explain the important role of decomposers in an ecosystem.  Compare the concept of a food chain with that of a food web.

Section 3 Energy Transfer Chapter 18 Producers  Autotrophs: manufacture their own food (plants, some protists and bacteria) Photosynthesis: most producers are photosynthetic and make carbohydrates by using energy from the sun. Chemosynthesis: used by some bacteria, process in which energy stored in inorganic molecules to produce carbohydrates.

Section 3 Energy Transfer Chapter 18 Producers  Measuring Productivity  Gross primary productivity is the rate at which producers in an ecosystem capture the energy of sunlight by producing organic compounds. Photosynthesis: H2O + CO2  C6H12O6 (glucose)  Net primary productivity is the rate at which biomass accumulates. Biomass is the result of organic material produced in an ecosystem as a result of growth and reproduction.

Section 3 Energy Transfer Chapter 18 Consumers  Consumers (heterotrophs) obtain energy by eating other organisms and include  Herbivores: eat producers  Omnivores: eat both producers and consumers  Carnivores: eat other consumers  Detritivores: eat waste  Decomposers: cause decay, break down of molecules.

Chapter 18 ClickComparing Producers and Consumers below to watch the Visual Concept.Comparing Producers and Consumers Section 3 Energy Transfer

Chapter 18 Energy Flow  Food Chains and Food Webs  A single pathway of energy transfer is a food chain.  A network showing all paths of energy transfer is a food web.  Trophic level indicates position in a sequence of energy transfers.

Chapter 18 Food Chain in an Antarctic Ecosystem Section 3 Energy Transfer

Chapter 18 Food Web in an Antarctic Ecosystem Section 3 Energy Transfer

Chapter 18 Energy Flow, continued  Energy Transfer  Ecosystems contain only a few trophic levels because there is a low rate of energy transfer between each level.

Chapter 18 Energy Transfer Through Trophic Levels Section 3 Energy Transfer An average of 10% of the energy consumed on one level is transferred to the next.

Section 4 Ecosystem Recycling Chapter 18 Objectives  List four major biogeochemical cycles.  Summarize three important processes in the water cycle.  Outline the major steps in the carbon cycle.  Describe the role of decomposers in the nitrogen cycle.  Summarize the major steps of the phosphorus cycle.

Section 4 Ecosystem Recycling Chapter 18 The Water Cycle  Key processes in the water cycle are evaporation, transpiration, and precipitation.

Chapter 18 Water Cycle Section 4 Ecosystem Recycling Water Cycle

Section 4 Ecosystem Recycling Chapter 18 The Carbon Cycle  Photosynthesis and cellular respiration are the two main steps in the carbon cycle. CO2 + H2O + energy  C6H12O6 + O2 Carbon dioxide water sun glucose oxygen C6H12O6 + O2  CO2 + H2O + energy glucose oxygen Carbon dioxide water heat

Chapter 18 Carbon Cycle Section 4 Ecosystem Recycling Carbon Cycle

Section 4 Ecosystem Recycling Chapter 18 Nitrogen Cycle  Nitrogen-fixing bacteria are important in the nitrogen cycle because they change nitrogen gas into a usable form of nitrogen for plants.

Chapter 18 Nitrogen Cycle Section 4 Ecosystem Recycling Nitrogen Cycle

Section 4 Ecosystem Recycling Chapter 18 Phosphorus Cycle  In the phosphorus cycle, phosphorus moves from phosphate deposited in rock, to the soil, to living organisms, and finally to the ocean. This presentation has been adapted from the Modern Biology Ch. 18 presentation.