Chapter 8: Community Ecology

Land and Water Use

II. The Living World (10-15%)

• 1. *Ecosystem Structure (Biological populations and communities; ecological niches; interactions among species; keystone species; species diversity and edge effects; major terrestrial and aquatic biomes)

• 2. *Energy Flow (Photosynthesis and cellular respiration; food webs and trophic levels; ecological pyramids)

• 3. *Ecosystem Diversity (Biodiversity; natural selection; evolution; ecosystem services)

• 4. *Natural Ecosystem Change (Climate shifts; species movement; ecological succession)

• 5. Natural Biogeochemical Cycles (Carbon, nitrogen, phosphorus, sulfur, water, conservation of matter)

mft

10

50

20

30100

Tropicalrain forest

Coniferousforest

Deciduousforest

Thornforest

Tall-grassprairie

Short-grassprairie

Desertscrub

Thornscrub

Terrestrial Communities

Michigan contains areas of this

II. The Living World (10-15%)

• 1. *Ecosystem Structure (Biological populations and communities; ecological niches; interactions among species; keystone species; species diversity and edge effects; major terrestrial and aquatic biomes)

• 2. *Energy Flow (Photosynthesis and cellular respiration; food webs and trophic levels; ecological pyramids)

• 3. *Ecosystem Diversity (Biodiversity; natural selection; evolution; ecosystem services)

• 4. *Natural Ecosystem Change (Climate shifts; species movement; ecological succession)

• 5. Natural Biogeochemical Cycles (Carbon, nitrogen, phosphorus, sulfur, water, conservation of matter)

Community descriptors• Physical appearance: distribution

(random, clumped, pattern), location, physical structures

• Species diversity: richness (number of types of species), evenness( abundance of individuals. Remember Shannon index? Affected by:– Latitude– pollution

• Niche structure: number of niches, overlap, interactions.

Latitude Effects on RichnessS

pec

ies

Div

ersi

ty

Sp

ecie

s D

iver

sity

1,000

100

10

Latitude

80ºN 60 40 20 0

200

100

0

90ºN 60 30 0 30ºS 60

Latitude

(a) Ants (b) Breeding birds

Number of individuals per diatom species

Nu

mb

er o

f d

iato

m s

pec

ies Unpolluted

stream

Pollutedstream

Pollution Effects on Richness, Evenness

II. The Living World (10-15%)

• 1. *Ecosystem Structure (Biological populations and communities; ecological niches; interactions among species; keystone species; species diversity and edge effects; major terrestrial and aquatic biomes)

• 2. *Energy Flow (Photosynthesis and cellular respiration; food webs and trophic levels; ecological pyramids)

• 3. *Ecosystem Diversity (Biodiversity; natural selection; evolution; ecosystem services)

• 4. *Natural Ecosystem Change (Climate shifts; species movement; ecological succession)

• 5. Natural Biogeochemical Cycles (Carbon, nitrogen, phosphorus, sulfur, water, conservation of matter)

MacArthur and Wilson

• Study done comparing small and large island biodiversity.

• Conclusions:– Small islands have less animals coming to it

because it is a small target to immigrate to.– Smaller islands have higher extinction rates

because of fewer resources and habitats– Islands closer to mainlands will have higher

immigration of animals.

II. The Living World (10-15%)

• 1. *Ecosystem Structure (Biological populations and communities; ecological niches; interactions among species; keystone species; species diversity and edge effects; major terrestrial and aquatic biomes)

• 2. *Energy Flow (Photosynthesis and cellular respiration; food webs and trophic levels; ecological pyramids)

• 3. *Ecosystem Diversity (Biodiversity; natural selection; evolution; ecosystem services)

• 4. *Natural Ecosystem Change (Climate shifts; species movement; ecological succession)

• 5. Natural Biogeochemical Cycles (Carbon, nitrogen, phosphorus, sulfur, water, conservation of matter)

Species• Native: species that normally live in an area. In

Iowa: whitetail deer, squirrel, bass, etc.• Non-native: AKA invasive or alien. Brought into

an area intentionally or accidentally. Can often overtake native species. Asian beetle, water milfoil, zebra mussel, etc.

• Indicator: species that will be affected first by environmental change. Trout (temperature), frogs, birds.

• Keystone: species that have an effect on a large number of other species. (pollination, predation, etc)

Why we love Kermit the Frog

• Amphibians are excellent indicator species.• Why?

– Lifecycle puts it in contact with land and water– Vulnerable to a wide variety of chemicals, radiation,

pollutants

• Frog species loss– Habitat loss– Pollution– Hunting (frog legs)– UV radiation

II. The Living World (10-15%)

• 1. *Ecosystem Structure (Biological populations and communities; ecological niches; interactions among species; keystone species; species diversity and edge effects; major terrestrial and aquatic biomes)

• 2. *Energy Flow (Photosynthesis and cellular respiration; food webs and trophic levels; ecological pyramids)

• 3. *Ecosystem Diversity (Biodiversity; natural selection; evolution; ecosystem services)

• 4. *Natural Ecosystem Change (Climate shifts; species movement; ecological succession)

• 5. Natural Biogeochemical Cycles (Carbon, nitrogen, phosphorus, sulfur, water, conservation of matter)

Nu

mb

er o

f in

div

idu

als

Nu

mb

er o

f in

div

idu

als

Resource use

Resource use

Species 1 Species 2

Regionof

niche overlap

Species 1 Species 2

Resource Partitioning

© 2004 Brooks/Cole – Thomson Learning

Hawks and Owls = same prey.

Hawks – hunt by day Owls – hunt by night

Resource Partitioning

Prey Defense Mechanisms

• Avoidance: Hedgehogs (rollup/spines), lizards tails that break off, turtle (shell),

• Camouflage: coloring, patterns, etc to help blend in. Deer, frogs, etc.

• Poison: Oleander plants, some frogs

• Foul smell/taste: Monarchs, skunks, etc.

• Warning color: bright color to show poisonous nature.

• Mimicry: Look like a poisonous animal, act like another (bull snake “rattling”)

Span worm Bombardier beetle

Viceroy butterfly

monarch butterfly

Poison dart frog snake caterpillar

Prey Defense Mechanisms

Wandering leaf insect

io moth

Camouflage Camouflage Foul smell

Mimicry

Foul taste

Mimicry MimicryPoison/Warning Color

II. The Living World (10-15%)

• 1. *Ecosystem Structure (Biological populations and communities; ecological niches; interactions among species; keystone species; species diversity and edge effects; major terrestrial and aquatic biomes)

• 2. *Energy Flow (Photosynthesis and cellular respiration; food webs and trophic levels; ecological pyramids)

• 3. *Ecosystem Diversity (Biodiversity; natural selection; evolution; ecosystem services)

• 4. *Natural Ecosystem Change (Climate shifts; species movement; ecological succession)

• 5. Natural Biogeochemical Cycles (Carbon, nitrogen, phosphorus, sulfur, water, conservation of matter)

Relationships

• Predator-Prey: “eat or be eaten”• Parasitism: one organism lives

off of another. Host is often weakened, but not killed. Examples: tapeworms, wood ticks, cowbird eggs.

• Mutualism: both species in relationship will benefit. Example: clown fish/sea anemone.

• Commensalism: one organism benefits, the other is not affected. Some doubt this exists as “some effect” must occur. Example: seeds traveling on animals

Review clip for visual

II. The Living World (10-15%)

• 1. *Ecosystem Structure (Biological populations and communities; ecological niches; interactions among species; keystone species; species diversity and edge effects; major terrestrial and aquatic biomes)

• 2. *Energy Flow (Photosynthesis and cellular respiration; food webs and trophic levels; ecological pyramids)

• 3. *Ecosystem Diversity (Biodiversity; natural selection; evolution; ecosystem services)

• 4. *Natural Ecosystem Change (Climate shifts; species movement; ecological succession)

• 5. Natural Biogeochemical Cycles (Carbon, nitrogen, phosphorus, sulfur, water, conservation of matter)

Primary Succession• Starts with: barren rock (land) or rock bottom of

lake, river, stream. Examples: area after volcanic eruption, glacier retreat.

• Pioneer species: usually lichen and moss. Begins to break down rock to make soil.

• Early successional plants: annuals, low growing, short lives.

• Midsuccessional plants: herbs, taller grasses, shrubs.

• Late successional plants: mostly trees. • Climax community (succession completed)• View clip

Time

Small herbsand shrubs

Heath mat

Jack pine,black spruce,

and aspen

Balsam fir,paper birch, and

white spruceclimax community

Exposedrocks

Lichensand mosses

Primary Succession

Review soil formation

Secondary Succession• Starts with: disaster or human activity

that destroys environment, but soil remains.

• Follows same process as Primary succession, but lengthy soil making process gets to be “skipped”

• First to re-grow: small grasses, plants then leads to larger shrubs and trees.

Time

Annualweeds

Perennialweeds and

grasses

ShrubsYoung pine forest

Mature oak-hickory forest

Secondary succession

Aquatic Succession• Starts with: newly formed pond/lake

• Typically from glacial retreat• Bottom is rocky.

• Sediment is brought in by runoff, erosion.• Plants able to grow on edges only.• Plant growth, death, decay leads to more

nutrients.• Normal eutrophication can lead to wetland,

then meadow.• Succession would end with grassland or

meadow

Aquatic Succession

So how much of your syllabus was covered

today in “biology” review material?

II. The Living World (10-15%)

• 1. *Ecosystem Structure (Biological populations and communities; ecological niches; interactions among species; keystone species; species diversity and edge effects; major terrestrial and aquatic biomes)

• 2. *Energy Flow (Photosynthesis and cellular respiration; food webs and trophic levels; ecological pyramids)

• 3. *Ecosystem Diversity (Biodiversity; natural selection; evolution; ecosystem services)

• 4. *Natural Ecosystem Change (Climate shifts; species movement; ecological succession)

• 5. Natural Biogeochemical Cycles (Carbon, nitrogen, phosphorus, sulfur, water, conservation of matter)