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Ecosystems and Living Organisms

Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

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Page 1: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Ecosystems and Living Organisms

Page 2: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Chapter Overview

I. Evolution

II. Succession

III. Keystone Species

IV. Symbiosis

V. Predation

VI. Competition

VII. Species Richness

Page 3: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The American Alligator

Page 4: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII
Page 5: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Diversity of Life

Kingdoms of Life

Page 6: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Diversity of Life

Species

Similar organisms

that have the

potential to

produce viable

offspring together.

Page 7: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Evolution

• Genetic changes in a population through time.

• Mechanism for how species changed was explained by Charles Darwin.

– Origin of Species, 1859

– Evolution occurs through natural selection.

• Inherited, favorable traits are “preserved”

• Inherited, UNfavorable traits are “eliminated”

• Adaptation - genetic traits that increases the chances of survival and reproductive success.

Page 8: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Evolution

Survival of the Fittest

species heritable traits most suitable for the

environment are most successful.

fitness – describes the success of an organism at

surviving and reproducing.

The number of fit individuals will increase in the

population, changing the frequency of favorable

traits in the population.

Page 9: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Evolution

• How does evolution cause a species to change

over time?

Overproduction

Variation

Struggle for existence

Differential reproductive success

Causes

allele

frequencies

to change

(=species

change)

Page 10: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Evolution

Page 11: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Evolution• Hardy-Weinberg Equilibrium

• Allele and gene frequencies do NOT change in an ideal population.

• Population must experience the following for HW to apply:

• No mutation

• No selection

• No migration

• No genetic drift

• Random mating

• Population will not evolve if the above factors are true.

Page 12: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Evolution

• Hardy-Weinberg Equilibrium

• Formula:

p2 + 2pq + q2 = 1

• p = frequency of dominant allele

• q = frequency of recessive allele

• The sum of these frequencies is 1 if the population is in

equilibrium.

Page 13: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Evolution

3 Types:

Page 14: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Modes of Action

Natural selection has three modes of action:

1. Stabilizing selection

2. Directional selection

3. Diversifying selection

Number

of

Individuals

Size of individuals

Small Large

Page 15: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

1. Stabilizing Selection

Acts upon extremes and

favors the intermediate

Number

of

Individuals

Size of individuals

Small Large

Page 16: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

2. Directional

SelectionFavors variants of one

extreme

Number

of

Individuals

Size of individuals

Small Large

Page 17: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

3. Diversifying

SelectionFavors variants of opposite

extremes

Number

of

Individuals

Size of individuals

Small Large

Page 18: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Coevolution

CoevolutionOne species acts as a selective force on a

second species Induces adaptations

Example:1. Wolf and Moose2. Acacia ants and Acacia trees3. Lichen

Page 20: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

20

At any given moment (e.g. the

‘present’), all we see is current

diversity…

all extinct forms are gone

(99.9%)

Page 21: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

21

BiodiversityBiodiversity increases with speciation decreases with extinction

Extinction creates evolutionary opportunities for surviving species

Page 22: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII
Page 23: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII
Page 24: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

24

Richness (number of species)

Relative abundance

Due to:

Evolutionary

history

Climate

Comparison of

Two Communities

Page 25: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

25

The larger the

geographic

area, the

greater

the number

of species

Species-Area Curve

Fig. 23.25 North American Birds

Page 26: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

26

Species Richness on Islands

Depends on:

Rate of immigration to island

Rate of extinction on island

These in turn depend on:

Island size

Distance from mainland

Page 27: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Species Richness

Species richness - Number of different species in a

community

Page 28: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Species Richness

Forest Grassland

EC

OT

ON

E

Where edge effect occurs - different

species composition

Typically greater species richness

Ecotone - transition zone where 2+ communities meet

Page 29: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Species Richness

Species Richness and Ecosystem Services

Ecosystem Ecosystem services

Forests,

Grasslands

Purify air / water

Produce / maintain soil

Absorb CO2

Wildlife habitat

Freshwater

systemsModerate water flow

Mitigate flooding

Dilute / remove pollutants

Drinking water

Recreation

Page 30: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Species Richness

Species Richness and Community Stability

Greater the richness = Greater the stability

- community stability

- ability of a community to withstand environmental

disturbance

Page 31: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

31

Threats to Ecosystem Stability

1. Drop in Primary Productivity

2. Increased Nutrient Losses

3. Decline or extinction of indicator species

4. Increased populations of insect pests or disease organisms

5. Decline in Species diversity

6. Presence of Contaminants

Page 32: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

32

How do species move? Humans (accidental and intended)

Animals (sticky seeds and scat)

Wind and ocean currents (+ or -)

Land bridges

Stepping stone islands affected by climactic changes (glaciation)

ocean levels

short-term weather patterns

Page 33: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Biological Communities

Rotting Log Community

Page 34: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Keystone Species

• Single species that strongly influences an entire

community.

• Example: figs

frugivores depend upon fruit

usually avoid figs, but during certain times of the year,

figs are only species bearing fruit

if figs were eliminated, many frugivores would die out

Page 35: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Interactions Among

Organisms Symbiosis –

one species living in or on another species

results from coevolution

Page 36: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Symbiosis

1) Mutualism - both partners benefit

Without mycorrhizae With mycorrhizae

Page 37: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Symbiosis

2) Commensalism - one partner benefits

and the other partner is neither harmed

nor helped.

Epiphytes

Page 38: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Symbiosis

3) Parasitism - one partner benefits

and the other partner is harmed

Tracheal mites

Page 39: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

39

Predator Adaptations Prey detection and recognition

sensory adaptations - distinguish prey

from non-prey

Discuss why each of the following demonstrates

sensory adaptations.

Page 40: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

40

Page 41: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

41

Predator Adaptations Prey detection and recognition

sensory adaptations - distinguish prey from non-prey

Prey capture

passive vs. active

individuals vs. cooperative

Determine if the following pictures are examples of passive or

active prey capture. Explain why.

Determine if the following pictures are examples of individual or

cooperative prey capture. Explain why.

Discuss the costs and benefits of each strategy.

.

Page 42: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

42

Page 43: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

43

Predator Adaptations Prey detection and recognition

sensory adaptations - distinguish prey from non-prey

Prey capture

passive vs. active

individuals vs. cooperative

Determine if the following pictures are examples of passive or

active prey capture. Explain why.

Determine if the following pictures are examples of individual or

cooperative prey capture. Explain why.

Discuss the costs and benefits of each strategy.

.

Page 44: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

44

Page 45: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

45

Predator Adaptations Prey detection and recognition

sensory adaptations - distinguish prey from non-prey

Prey capture

passive vs. active

individuals vs. cooperative

Eating prey

teeth, claws etc.

Describe why each of the following is an adaptation.

Page 46: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

46

Page 47: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

47

Prey AdaptationsAvoid detection

camouflage, mimics,

diurnal/nocturnal

Explain how natural selection leads to

camouflage and mimicry.

Page 48: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

48

Page 49: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

49

Prey AdaptationsAvoid detection

camouflage, mimics, warning coloration

diurnal/nocturnal

Avoid capture

Flee, resist, escape

Describe how each of the following examples

demonstrates avoidance of capture.

Page 50: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

50

Page 51: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

51

Prey Adaptations Avoid detection

camouflage, mimics,

diurnal/nocturnal

Avoid capture

flee

resist

escape

Disrupt handling (prevent being eaten)

struggle?

protection, toxins

Page 53: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

53

HerbivoryHerbivore needs to find most nutritious food sources.

circumvent plant defenses

Page 54: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

54

HerbivoryHerbivore needs to find most nutritious

circumvent plant defenses

Herbivory is a strong selective pressure on plants

structural adaptations for defense

chemical adaptations for defense

Explain why the following exemplifies coevolution.

Page 55: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

55

Page 56: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Predator-Prey Interactions Predator and prey populations are

interdependent.

Page 58: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Interactions Among

Organisms Competition –

individuals attempting to utilize common

resources

Intraspecific competition - between

individuals of same population

Interspecific competition - between

different species

Page 59: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The Ecological Niche

• All of an organism’s adaptations, use of resources,

lifestyle, and habitat.

– Fundamental vs. Realized Niche

• Fundamental Niche - potential, idealized

ecological niche

• Realized Niche - actual, realized ecological

niche

– Limiting Factor

• Environmental resource that restricts an

organism’s niche because of limited availability.

Page 60: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The Ecological Niche

Example: Tale of Two Anoles

Green Anole Brown Anole

Page 61: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The Ecological Niche

Fundamental vs. Realized Niche

Fundamental

Niche of

Green Anole

Fundamental

Niche of

Brown Anole

Overl

ap

Brown anole out-competes

green anole, therefore . . .

COMPETITION

Page 62: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The Ecological Niche

Fundamental vs. Realized Niche

Realized

Niche of

Green Anole

Overl

ap Realized

Niche of

Brown Anole

Page 63: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The Ecological Niche

Limiting Resources

Page 64: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The Ecological Niche

Competitive Exclusion

no 2 species can occupy the same niche indefinitely.

one species is excluded from part of the niche

because of interspecific competition.

Page 65: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The Ecological Niche

Competitive Exclusion

Page 66: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The Ecological Niche

Competitive Exclusion

Page 67: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

The Ecological Niche

Resource partitioning

coexisting species’ niches differ from each other in

more than one way.

Page 68: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Biological Communities

Succession:

Process of community development over time

Species in one phase of development are replaced by other species.

earlier species modify the environment

less competition for earlier species

Page 69: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

69

DisturbanceEvent that disrupts an ecosystem or community

• Natural disturbance

•tree falls, fires, hurricanes, tornadoes,

droughts, & floods

• Human–caused disturbance

•deforestation, erosion, overgrazing, plowing,

pollution, mining

• Disturbance can initiate primary and/or secondary

succession

Page 70: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Succession Two Types:

Primary succession

change in species composition in an environment that had not been established before.

no existing seed bank when development begins

pioneer community - initial community to develop

Secondary succession –

change in species composition after a disturbance destroys existing vegetation

Existing seed bank

Page 71: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Biological Communities

Primary succession –

Lichens

Mosses

Rocks

Page 72: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Biological Communities

Primary succession –

Rocks

Lichens

Mosses

Grasses

Shrubs

Page 73: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Biological Communities

Primary succession –

Rocks

Lichens

Mosses

Grasses

Shrubs

Trees

Page 74: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Biological Communities Secondary Succession

Page 76: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

76

Page 77: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Ecosystem Stability

Climax community – community that has reached a

“steady state”

Ecosystem stability – ecosystem that is resistant to

change.

Can an ecosystem have a climax community?

Page 78: Ecosystems and Living Organisms · Ecosystems and Living Organisms. Chapter Overview I. Evolution II. Succession III. Keystone Species IV. Symbiosis V. Predation VI. Competition VII

Increase biodiversity increase ecosystem stability