MILLERSPOOLMAN LIVING IN THE ENVIRONMENT 17 TH Chapter

MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT 17 TH Chapter 5 Biodiversity, Species Interactions, and Population Control

Core Case Study: Southern Sea Otters: Are They Back from the Brink of Extinction? • Habitat • Hunted: early 1900 s • Partial recovery • Why care about sea otters? • Ethics • Tourism dollars • Keystone species

Southern Sea Otter Fig. 5 -1 a, p. 104

5 -1 How Do Species Interact? • Concept 5 -1 Five types of species interactions— competition, predation, parasitism, mutualism, and commensalism—affect the resource use and population sizes of the species in an ecosystem.

Species Interact in 5/6 Major Ways • Intraspecific Competition • Interspecific Competition • Predation • Parasitism • Mutualism • Commensalism

Most Species Compete with One Another for Certain Resources • For limited resources • Ecological niche for exploiting resources • Some niches overlap

Some Species Evolve Ways to Share Resources • Resource partitioning • Using only parts of resource • Using at different times • Using in different ways

Resource Partitioning Among Warblers Fig. 5 -2, p. 106

Blackburnian Warbler Black-throated Green Warbler Cape May Warbler Bay-breasted Warbler Yellow-rumped Warbler Fig. 5 -2, p. 106

Blackburnian Warbler Black-throated Green Warbler Cape May Warbler Bay-breasted Warbler Yellow-rumped Warbler Stepped Art Fig. 5 -2, p. 106

Specialist Species of Honeycreepers Fig. 5 -3, p. 107

Fruit and seed eaters Insect and nectar eaters Greater Koa-finch Kuai Akialaoa Amakihi Kona Grosbeak Akiapolaau Crested Honeycreeper Maui Parrotbill Unknown finch ancestor Apapane Fig. 5 -3, p. 107

Most Consumer Species Feed on Live Organisms of Other Species (1) • Predators may capture prey by 1. Walking 2. Swimming 3. Flying 4. Pursuit and ambush 5. Camouflage 6. Chemical warfare 7. Going to restaurant or grocery store!

Predator-Prey Relationships Fig. 5 -4, p. 107

Most Consumer Species Feed on Live Organisms of Other Species (2) • Prey may avoid capture by 1. Run, swim, fly 2. Protection: shells, bark, thorns 3. Camouflage 4. Chemical warfare 5. Warning coloration 6. Mimicry 7. Deceptive looks 8. Deceptive behavior

Some Ways Prey Species Avoid Their Predators Fig. 5 -5, p. 109

(a) Span worm Fig. 5 -5 a, p. 109

(b) Wandering leaf insect Fig. 5 -5 b, p. 109

(c) Bombardier beetle Fig. 5 -5 c, p. 109

(d) Foul-tasting monarch butterfly Fig. 5 -5 d, p. 109

(e) Poison dart frog Fig. 5 -5 e, p. 109

(f) Viceroy butterfly mimics monarch butterfly Fig. 5 -5 f, p. 109

(g) Hind wings of Io moth resemble eyes of a much larger animal. Fig. 5 -5 g, p. 109

(h) When touched, snake caterpillar changes shape to look like head of snake. Fig. 5 -5 h, p. 109

(a) Span worm (c) Bombardier beetle (e) Poison dart frog (g) Hind wings of Io moth resemble eyes of a much larger animal. (b) Wandering leaf insect (d) Foul-tasting monarch butterfly (f) Viceroy butterfly mimics monarch butterfly (h) When touched, snake caterpillar changes shape to look like head of snake. Stepped Art Fig. 5 -5, p. 109

Science Focus: Threats to Kelp Forests • Kelp forests: biologically diverse marine habitat • Major threats to kelp forests 1. Sea urchins 2. Pollution from water run-off 3. Global warming

Purple Sea Urchin Fig. 5 -A, p. 108

Predator and Prey Interactions Can Drive Each Other’s Evolution • Intense natural selection pressures between predator and prey populations • Coevolution • Interact over a long period of time • Bats and moths: echolocation of bats and sensitive hearing of moths

Coevolution: A Langohrfledermaus Bat Hunting a Moth Fig. 5 -6, p. 110

Some Species Feed off Other Species by Living on or in Them • Parasitism • Parasite is usually much smaller than the host • Parasite rarely kills the host • Parasite-host interaction may lead to coevolution

Parasitism: Trout with Blood-Sucking Sea Lamprey Fig. 5 -7, p. 110

In Some Interactions, Both Species Benefit • Mutualism • Nutrition and protection relationship • Gut inhabitant mutualism • Not cooperation: it’s mutual exploitation

Mutualism: Hummingbird and Flower Fig. 5 -8, p. 110

(a) Birds and black rhinoceros Fig. 5 -9 a, p. 111

(b) Clownfish and sea anemone Fig. 5 -9 b, p. 111

In Some Interactions, One Species Benefits and the Other Is Not Harmed • Commensalism • Epiphytes • Birds nesting in trees

Commensalism: Bromiliad Roots on Tree Trunk Without Harming Tree Fig. 5 -10, p. 111

5 -2 What Limits the Growth of Populations? • Concept 5 -2 No population can continue to grow indefinitely because of limitations on resources and because of competition among species for those resources.

Most Populations Live Together in Clumps or Patches (1) • Population: group of interbreeding individuals of the same species • Population distribution 1. Clumping 2. Uniform dispersion 3. Random dispersion

Most Populations Live Together in Clumps or Patches (2) • Why clumping? 1. Species tend to cluster where resources are available 2. Groups have a better chance of finding clumped resources 3. Protects some animals from predators 4. Packs allow some to get prey

Population of Snow Geese Fig. 5 -11, p. 112

Generalized Dispersion Patterns Fig. 5 -12, p. 112

(a) Clumped (elephants) Fig. 5 -12 a, p. 112

(b) Uniform (creosote bush) Fig. 5 -12 b, p. 112

(c) Random (dandelions) Fig. 5 -12 c, p. 112

Populations Can Grow, Shrink, or Remain Stable (1) • Population size governed by • • Births Deaths Immigration Emigration • Population change = (births + immigration) – (deaths + emigration)

Populations Can Grow, Shrink, or Remain Stable (2) • Age structure • Pre-reproductive age • Reproductive age • Post-reproductive age

Some Factors Can Limit Population Size • Range of tolerance • Variations in physical and chemical environment • 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, etc

Trout Tolerance of Temperature Fig. 5 -13, p. 113

Lower limit of tolerance Few organisms Abundance of organisms Few organisms No organisms Population size No organisms Higher limit of tolerance Zone of intolerance physiological stress Low Optimum range Temperature Zone of physiological intolerance stress High Fig. 5 -13, p. 113

No Population Can Grow Indefinitely: J-Curves and S-Curves (1) • Size of populations controlled by limiting factors: • • • Light Water Space Nutrients Exposure to too many competitors, predators, infectious diseases, or AP classes!

No Population Can Grow Indefinitely: J-Curves and S-Curves (2) • Environmental resistance • All factors that act to limit the growth of a population • Carrying capacity (K) • Maximum population a given habitat can sustain

No Population Can Grow Indefinitely: J-Curves and S-Curves (3) • Exponential growth = “J” -curve • Starts slowly, then accelerates to carrying capacity when meets environmental resistance • Logistic growth = “S” -curve • Decreased population growth rate as population size reaches carrying capacity

Logistic Growth of Sheep in Tasmania Fig. 5 -15, p. 115

Number of sheep (millions) 2. 0 Population overshoots carrying capacity Carrying capacity 1. 5 Population recovers and stabilizes 1. 0 Exponential growth Population runs out of resources and crashes . 5 1800 1825 1850 1875 Year 1900 1925 Fig. 5 -15, p. 115

Science Focus: Why Do California’s Sea Otters Face an Uncertain Future? • Low biotic potential • Prey for orcas • Cat parasites • Thorny-headed worms • Toxic algae blooms • PCBs and other toxins • Oil spills

Population Size of Southern Sea Otters Off the Coast of So. California (U. S. ) Fig. 5 -B, p. 114

Case Study: Exploding White-Tailed Deer Population in the U. S. • 1900: deer habitat destruction and uncontrolled hunting • 1920 s– 1930 s: laws to protect the deer • Current population explosion for deer • Spread Lyme disease • Deer-vehicle accidents • Eating garden plants and shrubs • Ways to control the deer population

Mature Male White-Tailed Deer Fig. 5 -16, p. 115

When a Population Exceeds Its Habitat’s Carrying Capacity, Its Population Can Crash • A population exceeds the area’s carrying capacity • Reproductive time lag may lead to overshoot • Population crash • Damage may reduce area’s carrying capacity

Exponential Growth, Overshoot, and Population Crash of a Reindeer Fig. 5 -17, p. 116

Population overshoots carrying capacity Number of reindeer 2, 000 1, 500 Population crashes 1, 000 500 Carrying capacity 0 1910 1920 1930 Year 1940 1950 Fig. 5 -17, p. 116

Species Have Different Reproductive Patterns (1) • Some species • R-STRATEGIST • • Many, usually small, offspring Little or no parental care Massive deaths of offspring Insects, bacteria, algae • Rodents, etc.

Species Have Different Reproductive Patterns (2) • Other species • K-STRATEGIST • • Reproduce later in life Small number of offspring with long life spans Young offspring grow inside mother Long time to maturity Protected by parents, and potentially groups Humans Elephants

Under Some Circumstances Population Density Affects Population Size • Density-dependent population controls • • Predation Parasitism Infectious disease Competition for resources

Several Different Types of Population Change Occur in Nature • Stable • Irruptive • Population surge, followed by crash • Cyclic fluctuations, boom-and-bust cycles • Top-down population regulation • Bottom-up population regulation • Irregular

Population Cycles for the Snowshoe Hare and Canada Lynx Fig. 5 -18, p. 118

Population size (thousands) 160 Hare Lynx 140 120 100 80 60 40 20 0 1845 1855 1865 1875 1885 1895 1905 1915 1925 1935 Year Fig. 5 -18, p. 118

Humans Are Not Exempt from Nature’s Population Controls • Ireland • Potato crop in 1845 • Bubonic plague • Fourteenth century • AIDS • Global epidemic

5 -3 How Do Communities and Ecosystems Respond to Changing Environmental Conditions? • Concept 5 -3 The structure and species composition of communities and ecosystems change in response to changing environmental conditions through a process called ecological succession.

Communities and Ecosystems Change over Time: Ecological Succession • Natural ecological restoration • Primary succession • Secondary succession

Some Ecosystems Start from Scratch: Primary Succession • No soil in a terrestrial system • No bottom sediment in an aquatic system • Takes hundreds to thousands of years • Need to build up soils/sediments to provide necessary nutrients

Primary Ecological Succession Fig. 5 -19, p. 119

Exposed rocks Lichens and mosses Small herbs and shrubs Heath mat Balsam fir, paper birch, and white Jack pine, black spruce, spruce forest community and aspen Time Fig. 5 -19, p. 119

Lichens and Exposed mosses rocks Small herbs and shrubs Heath mat Jack pine, black spruce, and aspen Balsam fir, paper birch, and white spruce forest community Time Stepped Art Fig. 5 -19, p. 119

Some Ecosystems Do Not Have to Start from Scratch: Secondary Succession (1) • Some soil remains in a terrestrial system • Some bottom sediment remains in an aquatic system • Ecosystem has been • Disturbed • Removed • Destroyed

Natural Ecological Restoration of Disturbed Land Fig. 5 -20, p. 120

Annual weeds Perennial weeds and grasses Shrubs and small pine seedlings Young pine forest with developing understory of oak and hickory trees Mature oak and hickory forest Time Fig. 5 -20, p. 120

Annual weeds Perennial weeds and grasses Shrubs and small pine seedlings Young pine forest with developing understory of oak and hickory trees Mature oak and hickory forest Time Stepped Art Fig. 5 -20, p. 120

Secondary Ecological Succession in Yellowstone Following the 1998 Fire Fig. 5 -21, p. 120

Some Ecosystems Do Not Have to Start from Scratch: Secondary Succession (2) • Primary and secondary succession • Tend to increase biodiversity • Increase species richness and interactions among species • Primary and secondary succession can be interrupted by • • • Fires Hurricanes Clear-cutting of forests Plowing of grasslands Invasion by nonnative species

Science Focus: How Do Species Replace One Another in Ecological Succession? • Facilitation • Inhibition • Tolerance

Succession Doesn’t Follow a Predictable Path • Traditional view • Balance of nature and a climax community • Current view • Ever-changing mosaic of patches of vegetation • Mature late-successional ecosystems • State of continual disturbance and change

Living Systems Are Sustained through Constant Change • Inertia, persistence • 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 • Some systems have one property, but not the other: tropical rainforests

Three Big Ideas 1. Certain interactions among species affect their use of resources and their population sizes. 2. There always limits to population growth in nature. 3. Changes in environmental conditions cause communities and ecosystems to gradually alter their species composition and population sizes (ecological succession).