Biodiversity, Species Interactions, and Population Controltvhsapes.weebly.com/uploads/7/5/9/5/75954777/chapter_5_notes.pdfSouthern Sea Otter Fig. 5-1, p. 102 . Figure 5.1 An endangered

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LIVING IN THE ENVIRONMENT, 18e G. TYLER MILLER • SCOTT E. SPOOLMAN


5 Biodiversity, Species Interactions, and Population Control


• Live in giant kelp forests • By the early 1900s they had been hunted

almost to extinction • Partial recovery since 1977 • Why care about sea otters?

– Ethics – Tourism dollars – Keystone species

Core Case Study: Southern Sea Otters - A Species in Recovery


Southern Sea Otter

Fig. 5-1, p. 102

Presenter

Presentation Notes

Figure 5.1 An endangered southern sea otter in Monterey Bay, California (USA) uses a stone to crack the shells of clams that it feeds on (left). It lives in a giant bed of seaweed called kelp (right).�


• Five types of species interactions—competition, predation, parasitism, mutualism, and commensalism—affect the resource use and population sizes of the species in an ecosystem

5-1 How Do Species Interact?


• Five basic types of interactions – Interspecific Competition – Predation – Parasitism – Mutualism – Commensalism

• Interspecific competition – Compete to use the same limited resources

Most Species Compete with One Another for Certain Resources


• Resource partitioning • Species may use only parts of resource

– At different times – In different ways

Some Species Evolve Ways to Share Resources


Cape May Warbler

Stepped Art

Blackburnian Warbler

Black-throated Green Warbler

Yellow-rumped Warbler

Bay-breasted Warbler

Fig. 5-2, p. 103

Sharing the Wealth

Presenter

Presentation Notes

Figure 5.2 Sharing the wealth: Resource partitioning among five species of insect-eating warblers in the spruce forests of the U.S. state of Maine. Each species spends at least half its feeding time in its associated yellow-highlighted areas of these spruce trees.�


Fig. 5-3, p. 104

Fruit and seed eaters Insect and nectar eaters Greater Koa-finch

Kuai Akialaoa

Amakihi Kona Grosbeak

Crested Honeycreeper Akiapolaau

Maui Parrotbill Apapane

Unkown finch ancestor

Specialist Species of Honeycreepers

Presenter

Presentation Notes

Figure 5.3 Specialist species of honeycreepers: Through natural selection, different species of honeycreepers have shared resources by evolving specialized beaks to take advantage of certain types of food such as insects, seeds, fruits, and nectar from certain flowers. Question: Look at each bird’s beak and take a guess at what sort of food that bird might eat.


• Predator – feeds directly on all or part of a living organism

• Carnivores – Pursuit and ambush – Camouflage – Chemical warfare

Consumer Species Feed on Other Species


• Prey can avoid predation – Camouflage – Chemical warfare – Warning coloration – Mimicry – Behavioral strategies

Consumer Species Feed on Other Species (cont’d.)

Predator-Prey Relationships

Fig. 5-4, p. 104

Presenter

Presentation Notes

Figure 5-4: Predator-prey relationship: This brown bear (the predator) in the U.S. state of Alaska has captured and will feed on this salmon (the prey).


Predator-Prey Relationships

Fig. 5-6, p. 106

Presenter

Presentation Notes

Figure 5-6 These prey species have developed specialized ways to avoid their predators: (a, b) camouflage, (c, d, e) chemical warfare, (d, e, f) warning coloration, (f) mimicry, (g) deceptive looks, and (h) deceptive behavior.


• Intense natural selection pressures between predator and prey populations

• Coevolution – Interact over a long period of time – Changes in the gene pool of one species can

cause changes in the gene pool of the other – Bats and moths

• Echolocation of bats and sensitive hearing of moths

Interactions between Predator and Prey Species

Coevolution

Fig. 5-7, p. 107

Presenter

Presentation Notes

Figure 5-7: Coevolution: This bat is using ultrasound to hunt a moth. As the bats evolve traits to increase their chance of getting a meal, the moths evolve traits to help them avoid being eaten.


• Parasitism – Parasite is usually much smaller than the host – Parasite rarely kills the host – Parasite-host interaction may lead to

coevolution

Some Species Feed off Other Species by Living on or inside Them

Parasitism

Fig. 5-8, p. 107

Presenter

Presentation Notes

Figure 5-8: Parasitism: This blood-sucking, parasitic sea lamprey has attached itself to an adult lake trout from the Great Lakes (USA, Canada).


• Mutualism – Nutrition and protective relationship – Gut inhabitant mutualism – Not cooperation – mutual exploitation

In Some Interactions, Both Species Benefit

Mutualism

Fig. 5-9, p. 108

Presenter

Presentation Notes

Figure 5-9: Mutualism: Oxpeckers feed on parasitic ticks that infest animals such as this impala and warn of approaching predators.


• Commensalism – Benefits one species and has little affect on

the other – Epiphytes – Birds nesting in trees

In Some Interactions, One Species Benefits and the Other Is Not Harmed

Commensalism

Fig. 5-10, p. 108

Presenter

Presentation Notes

Figure 5-10: In an example of commensalism, this pitcher plant is attached to a branch of a tree without penetrating or harming the tree. This carnivorous plant feeds on insects that become trapped inside it.


• How do communities and ecosystems respond to changing environmental conditions? – The structure and species composition of

communities and ecosystems change in response to changing environmental conditions through a process called ecological succession

5-2 Responding to Changing Environmental Conditions


• Ecological succession – Gradual change in species composition – Primary succession

• In lifeless areas

– Secondary succession • Areas of environmental disturbance

– Examples of natural ecological restoration

Communities and Ecosystems Change over Time: Ecological Succession

Primary Ecological Succession

Balsam fir, paper birch, and white spruce forest community

Jack pine, black spruce, and aspen Heath mat Small herbs

and shrubs Lichens and mosses

Exposed rocks

Fig. 5-11, p. 109

Presenter

Presentation Notes

Figure 5.11 Primary ecological succession: Over almost a 1,000 years, these plant communities developed, starting on bare rock exposed by a retreating glacier on Isle Royal, Michigan (USA) in western Lake Superior. The details of this process vary from one site to another.

Natural Ecological Restoration

Mature oak and hickory forest

Shrubs and small pine seedlings

Young pine forest with developing understory of oak and hickory trees

Perennial weeds and grasses

Annual weeds

Fig. 5-12, p. 110

Presenter

Presentation Notes

Animated Figure 5.12 Natural ecological restoration of disturbed land: This diagram shows the undisturbed secondary ecological succession of plant communities on an abandoned farm field in the U.S. state of North Carolina. It took 150–200 years after the farmland was abandoned for the area to become covered with a mature oak and hickory forest.


• Traditional view – Balance of nature and climax communities

• Current view – Ever-changing mosaic of patches of

vegetation in different stages of succession

Ecological Succession Does Not Follow a Predictable Path


• Inertia – Ability of a living system to survive moderate

disturbances • Resilience

– Ability of a living system to be restored through secondary succession after a moderate disturbance

Living Systems Are Sustained through Constant Change


• No population can grow indefinitely because of limitations on resources and because of competition among species for those resources

What Limits the Growth of Populations


• Population – Group of interbreeding individuals of the same

species • Population distribution

– Clumping • Species cluster for resources • Protection from predators • Ability to hunt in packs

Most Populations Live in Clumps

A School of Anthias Fish

Fig. 5-13, p. 111

Presenter

Presentation Notes

Figure 5-13: A population, or school, of Anthias fish on coral in Australia’s Great Barrier Reef.


• Population size governed by: – Births and deaths; immigration and emigration

• Population change = (births + immigration) – (deaths + emigration)

• Age structure – Pre-reproductive age – Reproductive age – Post-reproductive age

Populations Can Grow, Shrink, or Remain Stable


• Range of tolerance – Variations in physical and chemical

environment – Individuals may have different tolerance

ranges

Some Factors Can Limit Population Size


• Limiting factor principle – Too much or too little of any physical or

chemical factor can limit or prevent growth of a population, even if all other factors are at or near the optimal range of tolerance

– Precipitation, nutrients, sunlight • Populations density

– Number of individuals in a given area

Some Factors Can Limit Population Size


Fig. 5-13, p. 113

Lower limit of tolerance

Higher limit of tolerance

No organisms

Few organisms Abundance of organisms

Few organisms

No organisms

Popu

latio

n si

ze

Zone of physiological

stress

Optimum range Zone of physiological

stress

Zone of intolerance

Low Temperature High

Zone of intolerance

Trout Tolerance of Temperature

Presenter

Presentation Notes

Figure 5.15 Range of tolerance for a population of trout to changes in water temperature.


• Some species: – Have many small offspring – Little parental involvement

• Other species: – Reproduce later in life – Have small number of offspring

Different Species Have Different Reproductive Patterns


• There are always limits to population growth in nature

• Environmental resistance – factors that limit population growth

• Carrying capacity – Maximum population of a given species that a

particular habitat can sustain indefinitely

No Population Can Grow Indefinitely: J-Curves and S-Curves


• Exponential growth – At a fixed percentage per year

• Logistic growth – Population faces environmental resistance

No Population Can Grow Indefinitely: J-Curves and S-Curves (cont’d.)

Fig. 5-16, p. 115

2.0

Population overshoots carrying capacity

Carrying capacity

1.5 Population recovers and stabilizes

Num

ber o

f she

ep (m

illio

ns)

.5

Exponential growth

Population runs out of resources and crashes

1.0

1800 1825 1850 1875 1900 1925 Year

Environmental resistance

Growth of a Sheep Population

Presenter

Presentation Notes

Animated Figure 5.16 Growth of a sheep population on the island of Tasmania between 1800 and 1925. After sheep were introduced in 1800, their population grew exponentially thanks to an ample food supply and few predators. By 1855, they had overshot the land’s carrying capacity. Their numbers then stabilized and fluctuated around a carrying capacity of about 1.6 million sheep.


• 1900 – deer habitat destruction and uncontrolled hunting

• 1920s–1930s – laws to protect the deer • Current deer population explosion

– Spread Lyme disease – Deer-vehicle accidents – Eating garden plants and shrubs

• How can we control the deer population?

Case Study: Exploding White-Tailed Deer Population in the U.S.

White-Tailed Deer Populations

Fig. 5-17, p. 115

Presenter

Presentation Notes

Figure 5-17: White-tailed deer populations in the United States have been growing.


• A population exceeds the area’s carrying capacity

• Reproductive time lag may lead to overshoot – Subsequent population crash

• Damage may reduce area’s carrying capacity

When a Population Exceeds Its Carrying Capacity It Can Crash


Fig. 5-18, p. 116

2,000 Population overshoots carrying capacity

1,500 Population crashes

1,000

500 Carrying capacity

Num

ber o

f rei

ndee

r

1910 1920 1930 1940 1950 0

Year

Population Crash

Presenter

Presentation Notes

Figure 5.18 Exponential growth, overshoot, and population crash of reindeer introduced onto the small Bering Sea island of St. Paul in 1910.


• Ireland – Potato crop in 1845

• Bubonic plague – Fourteenth century

• AIDS – Current global epidemic

Humans Are Not Exempt from Nature’s Population Controls


• Certain interactions among species – Affect their use of resources and their

population sizes • Changes in environmental conditions

– Cause communities and ecosystems to gradually alter their species composition and population sizes (ecological succession)

• There are always limits to population growth in nature

Three Big Ideas


• Before European settlers in the U.S., the sea otter ecosystem was complex

• Settlers began hunting otters – Disturbed the balance of the ecosystem

• Populations depend on solar energy and nutrient cycling – When these are disrupted biodiversity is

threatened

Tying It All Together – Southern Sea Otters and Sustainability

Documents

Biodiversity, Species Interactions, and Population Controltvhsapes.weebly.com/uploads/7/5/9/5/75954777/chapter_5_notes.pdfSouthern Sea Otter Fig. 5-1, p. 102 . Figure 5.1 An endangered