Download Section 1 Introduction to Ecology Chapter 18

Chapter 18
Introduction to Ecology
Table of Contents
Section 1 Introduction to Ecology
Section 2 Ecology of Organisms
Section 3 Energy Transfer
Section 4 Ecosystem Recycling
Chapter 18
Section 1 Introduction to Ecology
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.
Chapter 18
Section 1 Introduction to Ecology
Ecological Models

Ecological models help to explain the
environment.
Chapter 18
Section 1 Introduction to Ecology
Making an Ecosystem Model
Chapter 18
Section 1 Introduction to Ecology
Levels of Organization

Ecologists recognize a hierarchy of
organization in the environment: biosphere,
ecosystem, community, population, and
organism.
Chapter 18
Section 1 Introduction to Ecology
Levels of Organization
Chapter 18
Section 1 Introduction to Ecology
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.
Chapter 18
Section 1 Introduction to Ecology
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
Section 1 Introduction to Ecology
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
Chapter 18
Section 2 Ecology of Organisms
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.
Chapter 18
Section 2 Ecology of Organisms
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
Chapter 18
Section 2 Ecology of Organisms
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.
Chapter 18
Section 2 Ecology of Organisms
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)
http://www.richardseaman.com/Reptiles/Usa/Nevada/ValleyOfFire/HornedLizardCrouching.jpg
http://www.cc.gatech.edu/cpl/projects/graphcuttextures/data/rotationperspective/people-out-persp.gif
Chapter 18
Section 2 Ecology of Organisms
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
Chapter 18
Section 2 Ecology of Organisms
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
http://www.itee.uq.edu.au/~adc2010/koala.jpg
http://www.manataka.org/Raccoon%20Tongue%20Out.jpg
Chapter 18
Section 2 Ecology Of Organisms
Earthworm Niche
Chapter 18
Section 3 Energy Transfer
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.
Chapter 18
Section 3 Energy Transfer
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.
Chapter 18
Section 3 Energy Transfer
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.
Chapter 18
Section 3 Energy Transfer
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
Section 3 Energy Transfer
ClickComparing Producers and Consumers below
to watch the Visual Concept.
Chapter 18
Section 3 Energy Transfer
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
Section 3 Energy Transfer
Food Chain in an Antarctic Ecosystem
Chapter 18
Section 3 Energy Transfer
Food Web in an Antarctic Ecosystem
Chapter 18
Section 3 Energy Transfer
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
Section 3 Energy Transfer
Energy Transfer Through Trophic
Levels
An average of 10% of the energy consumed on one level is transferred to the
next.
Chapter 18
Section 4 Ecosystem Recycling
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.
Chapter 18
Section 4 Ecosystem Recycling
The Water Cycle

Key processes in the water cycle are
evaporation, transpiration, and precipitation.
Chapter 18
Section 4 Ecosystem Recycling
Water Cycle
Water Cycle
Chapter 18
Section 4 Ecosystem Recycling
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
Section 4 Ecosystem Recycling
Carbon Cycle
Carbon Cycle
Chapter 18
Section 4 Ecosystem Recycling
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
Section 4 Ecosystem Recycling
Nitrogen Cycle
Nitrogen Cycle
Chapter 18
Section 4 Ecosystem Recycling
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.