6 TH. Most Species Compete with One Another for Certain Resources. Species Interact in Five Major Ways. Some Species Evolve Ways to Share Resources

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1 Endangered species: Southern Sea Otter MILLER/SPOOLMAN ESSENTIALS OF ECOLOGY 6 TH Chapter 5 Biodiversity, Species Interactions, and Population Control Fig. 5-1a, p. 104 Species Interact in Five Major Ways Interspecific competition Predation Parasitism Mutualism Most Species Compete with One Another for Certain Resources For limited resources Ecological niche for exploiting resources Some niches overlap Commensalism Some Species Evolve Ways to Share Resources Resource partitioning Using only parts of resource Resource Partitioning Among Warblers Using at different times Using in different ways Fig. 5-2, p

2 Specialist Species of Honeycreepers Predator Prey Relationships Fig. 5-3, p. 107 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 (a) Span worm Fig. 5-5a, p. 109 (b) Wandering leaf insect Fig. 5-5b, p. 109 (c) Bombardier beetle Fig. 5-5c, p

3 (d) Foul-tasting monarch butterfly Fig. 5-5d, p. 109 (e) Poison dart frog Fig. 5-5e, p. 109 (f) Viceroy butterfly mimics monarch butterfly Fig. 5-5f, p. 109 (g) Hind wings of Io moth resemble eyes of a much larger animal. Fig. 5-5g, p. 109 Science Focus: Threats to Kelp Forests Kelp forests: biologically diverse marine habitat Major threats to kelp forests 1 Sea urchins 1. Sea urchins 2. Pollution from water run off 3. Global warming (h) When touched, snake caterpillar changes shape to look like head of snake. Fig. 5-5h, p

4 Purple Sea Urchin 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 Fig. 5-A, p. 108 Coevolution: A Langohrfledermaus Bat Hunting a Moth Parasitism: Trout with Blood Sucking Sea Lamprey Fig. 5-6, p. 110 Fig. 5-7, p. 110 Mutualism: Hummingbird and Flower Mutualism: Oxpeckers Clean Rhinoceros; Anemones Protect and Feed Clownfish Fig. 5-8, p. 110 Fig. 5-9, p

5 Commensalism: Bromiliad Roots on Tree Trunk Without Harming Tree Most Populations Live Together in Clumps or Patches (1) Population distribution 1. Clumping 2. Uniform dispersion 3. Random dispersion Fig. 5-10, p. 111 Population of Snow Geese Generalized Dispersion Patterns Fig. 5-11, p. 112 Fig. 5-12, p. 112 Populations Can Grow, Shrink, or Remain Stable (1) Population size governed by Births Deaths Immigration Emigration Populations Can Grow, Shrink, or Remain Stable (2) Age structure Pre reproductive age Reproductive age Post reproductive age Population change = (births + immigration) (deaths + emigration) 5

6 Trout Tolerance of Temperature 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 or infectious diseases Fig. 5-13, p. 113 No Population Can Grow Indefinitely: J Curves and S Curves (2) Environmental resistance All factors that act to limit the growth of a population Carryingcapacity (K) Maximum population a given habitat can sustain No Population Can Grow Indefinitely: J Curves and S Curves (3) Exponential growth Starts slowly, then accelerates to carrying capacity when meets environmental resistance Logistic growth Decreased population growth rate as population size reaches carrying capacity Logistic Growth of Sheep in Tasmania 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 Fig. 5-15, p

7 Population Size of Southern Sea Otters Off the Coast of So. California (U.S.) Case Study: Exploding White Tailed Deer Population in the U.S. 1900: deer habitat destruction and uncontrolled hunting 1920s 1930s: 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 Fig. 5-B, p. 114 Mature Male White Tailed Deer 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 Fig. 5-16, p. 115 Exponential Growth, Overshoot, and Population Crash of a Reindeer Species Have Different Reproductive Patterns (2) Other species Reproduce later in life Small number of offspring with long life spans Young offspring grow inside mother g p gg Long time to maturity Protected by parents, and potentially groups Humans Elephants Fig. 5-17, p

8 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 Communities and Ecosystems Change over Time: Ecological Succession Natural ecological restoration Primary succession Secondary succession Fig. 5-18, p. 118 Some Ecosystems Start from Scratch: Primary Succession No soil in a terrestrial system Primary Ecological Succession No bottom sediment in an aquatic system Takes hundreds to thousands of years Need to build up soils/sediments to provide necessary nutrients Fig. 5-19, p

9 Natural Ecological Restoration of Disturbed Land Secondary Ecological Succession in Yellowstone Following the 1998 Fire Fig. 5-20, p. 120 Fig. 5-21, p