Transcript Slide 1

Principles of
Ecology
Chapter 13
Review
 What is a system?
 Smaller parts working together,
organized into a larger whole
 What systems are you a part of?
 We, as animals, are all part of an
ecosystem.
 We interact with the environment to get
energy and materials.
How does this bird interact
with its ecosystem?
 How does the anhinga
interact with its
environment?
 Matter and energy, in the
form of food, move through
an ecosystem from
producers to consumers.
 Producers, such as plants
and algae, are organisms
that bring energy into an
ecosystem.
 What is the ultimate source
of energy?
What is Ecology?
 The study of interactions among
living things, and between living
things and their surroundings.
Ecologists study
environments at
different levels of
organization
Organism
 Individual living thing
Population
 Group of the same species that lives in one area
Community
 Group of different species that live together in
one area
 Just living
Ecosystem: living + nonliving
 Community and its nonliving surroundings
 Includes all of the organisms as well as the climate, soil,
water, rocks, and other nonliving things
Biome
 Major regional or global community of organisms
 Usually characterized by its climate conditions and plant
communities
Vocabulary to know!
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Ecology
Community
Biome
Biotic
Abiotic
Keystone species
Autotroph
Heterotroph
Producer
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Consumer
Food chain
Herbivore
Omnivore
Carnivore
Detritivore
Decomposer
Trophic Level
Food Web
Specialist
Generalist
An ecosystem includes both
biotic and abiotic factors
 Biotic factors: living things
 Examples: plants, animals, fungi,
bacteria
 Each organism plays a particular
role in the ecosystem.
An ecosystem includes both
biotic and abiotic factors
 Abiotic factors: nonliving thigns
 Examples: moisture, temperature,
wind, sunlight, and soil
 Balance of factors determines if
living things survive or not
Changing one factor in an ecosystem
can affect many other factors
 The loss of a single species may cause a
ripple effect across an entire ecosystem
 Keystone species: a species that has an
unusually large effect on its ecosystem
Energy in Ecosystems
 Producers: organisms that get their
energy from nonliving resources
 Make their own food
 Also called autotrophs
 Consumers: organisms that get their
energy by eating other live or once-living
resources (plants and animals)
 Also called heterotrophs
All ecosystems depend on
producers
 Producers provide the basis for the
ecosystem’s energy
 All consumers depend on producers
 But could producers survive without consumers?
 Most producers depend on the sun as their
source of energy
 Use process of photosynthesis
 Few producers live deep below a lake’s
surface…Why?
A few producers do not
depend on sunlight
 Some producers obtain energy through
process of chemosynthesis
 Chemosynthesis: process by which an
organism uses chemical as an energy
sources
 Several reactions change the chemicals into
usable energy
Types of Consumers
 Herbivores: organisms that eat only plants
 Carnivores: organisms that eat only
animals
 Omnivores: organisms that eat both plants
and animals
Types of Consumers cont.
 Detritivores: organisms that eat dead
organic matter (detritus)
 Example: earthworm
 Decomposers: detritivores that break
down organic matter into simpler
compounds
 Examples: bacteria and fungi
 Important because they return vital nutrients
back to the environment
Practice!
 I eat dead organic matter
 I eat only other animals
 I eat both plants and animals
 I eat only plants
 I break down organic matter into
simpler compounds
Specialists vs. Generalists
 Specialist: consumer that primarily eats one
specific organism or feeds on a very small
number of organisms
 Very sensitive to changes in the availability of prey
 Generalists: consumers that have a varying
diet
 Do not rely on a single source of food
 What danger does a specialist face that a
generalist does not?
Objective of this section
 Illustrate the flow of energy through an
ecosystem using food chains, trophic
levels, and food webs
Food Chains
 The simplest way to show how matter
and energy flow through an ecosystem is
using a food chain
 Food chain: a model that links organisms
by their feeding relationships
 Only follows the connection between one
producer and a single chain of
consumers within an ecosystem
Food Chain Example
 Producer (grass) is fed
upon by a herbivore
(grazing antelope) which is
fed upon by a carnivore
(coyote)
 Now you come up with a
different example using at
least 3 steps!
 Write it in words and draw
it on your own sheet of
paper
 Show me when you are
done
Trophic Levels
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Levels of nourishment
in a food chain
1. Producers: autotrophs
(plants)
2. Consumers:
heterotrophs
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Primary consumers:
herbivores
Secondary consumers:
carnivores
Tertiary consumers:
omnivores (predators)
Food Webs
 Food web: model that shows all of the
possible feeding relationships at each
level of a community
So what is the difference
between a food chain and a food
web?
 Food chains follow a single path as animals eat
each other
 GRASS is eaten by a GRASSHOPPER which is eaten by a
FROG which is eaten by a SNAKE which is eaten by a HAWK
 Food webs show how many animals are
interconnected by different paths
 TREES produce acorns which act as food for many MICE and
INSECTS. Because there are many MICE, the WEASELS,
SNAKES, and RACOONS, have food. The insects and the
acorns also attract BIRDS, SKUNKS, and OPOSSUMS. With
the SKUNKS, OPPOSUMS, WEASELS and MICE around,
HAWKS, FOXES, and OWLS can find food. They are all
connected!
So what is the difference
between food chains and
food webs?
Food Web Project Day 1
1. You will work with a partner that I choose
randomly for you.
2. First, determine the environment you want to use
(marine, desert, meadow, wetlands, etc)
3. Come up with a list of organisms that you will
include in your food web. You must have the
following:
a.
b.
c.
d.
e.
1 decomposer
3 different producers
3 herbivores (primary consumers)
3 carnivores (secondary consumers)
2 top predators (tertiary consumers)
Food Web Project Day 2
4. Approve list of organisms with me to get
your posterboard
5. Illustrate and color each organism
represented in the food web
6. For each organism, label the following:
a. Name of organism (ex: shark)
b. Type of consumer (shark is a carnivore)
c. Trophic Level (shark is a tertiary consumer, top
predator)
Pyramid Models
 Energy pyramids show the distribution of
energy among trophic levels
 Thoughout a food chain, energy is lost
 Each level in the food chain contains
much less energy than the level below it
 Between each level, up to 90% of the
energy could be lost as heat into the
atmosphere
Energy Pyramids
 Energy pyramid: a
diagram that compares
energy used by
producers, primary
consumers, and other
trophic levels
 It illustrates how
available energy is
distributed among trophic
levels in an ecosystem
Biomass Pyramids
 Biomass pyramid: a diagram that compares the biomass of
different trophic levels within an ecosystem
 Biomass: measure of the total dry mass of organisms in a given
area
 Show mass of producers needed to support primary
consumers, mass of primary consumers required to support
secondary consumers, and so on
Pyramid of Numbers
 Shows the numbers of individual organisms at
each trophic level in an ecosystem
 Effective at showing the vast number of
producers required to support even a few top
level consumers
Flip it!
 Both biomass pyramids and pyramids of
numbers may occur upside down
 Example: a pyramid of numbers based
on a single tree
 Upper tiers of the pyramid (representing
primary and secondary consumers like
insects and birds) would be much larger
than the bottom tier representing the tree