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Ch.7. Unit 3 – Life on Earth (Ecology) Part 2. Why are there so many species on Earth?. Genetic Diversity + Limited Resources Competitive Exclusion Evolution by Natural Selection Biological Diversity. Ch.7. Unit 3 – Life on Earth (Ecology) Part 2. Competitive Exclusion.

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slide1

Ch.7

Unit 3 – Life on Earth (Ecology) Part 2

Why are there so many species on Earth?

Genetic Diversity + Limited Resources

Competitive Exclusion

Evolution by Natural Selection

Biological Diversity

slide2

Ch.7

Unit 3 – Life on Earth (Ecology) Part 2

Competitive Exclusion

Two species that have exactly the same requirements cannot coexist in exactly the same environment

This can lead to either:

Extinction of one species

(or a change in allelic frequencies of a single species)

Or

A partitioning of resources

slide3

Ch.7

Unit 3 – Life on Earth (Ecology) Part 2

Avocet sweeps bill through

mud and surface water in

search of small crustaceans,

insects, and seeds

Ruddy turnstone searches

under shells and pebbles

for small invertebrates

Herring gull is a

tireless scavenger

Brown pelican dives for fish,

which it locates from the air

Dowitcher probes deeply

into mud in search of

snails, marine worms,

and small crustaceans

Black skimmer

seizes small fish

at water surface

Louisiana heron wades into

water to seize small fish

Piping plover feeds

on insects and tiny

crustaceans on

sandy beaches

Oystercatcher feeds on

clams, mussels, and

other shellfish into which

it pries its narrow beak

Flamingo

feeds on

minute

organisms

in mud

Scaup and other

diving ducks feed on mollusks, crustaceans,and aquatic vegetation

Knot (a sandpiper)

picks up worms and

small crustaceans left

by receding tide

Resource partitioning reduces competition and allows sharing of limited resources.

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Ch.7

Unit 3 – Life on Earth (Ecology) Part 2

This partitioning of resources leads to the formation of

Ecological Niches

A specie’s role or way of life

  • Fundamental niche: the full potential range of physical, chemical, and biological conditions and resources a species could theoretically use.
  • Realized niche: to survive and avoid competition, a species usually occupies only part of its fundamental niche.
slide5

Ch.7

Unit 3 – Life on Earth (Ecology) Part 2

Evolution by Natural Selection:

Leaving more offspring with beneficial traits

Evolution by Genetic Drift:

Changes in gene frequency due to chance

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Ch.7

Unit 3 – Life on Earth (Ecology) Part 2

Sympatric Speciation (Behavioral Isolation)

Allopatric Speciation (Geographic Isolation)

…can lead to reproductive isolation, divergence of gene pools and speciation.

slide7

Ch.7

Unit 3 – Life on Earth (Ecology) Part 2

Biodiversity

  • Genetic Diversity – total number of genes in a species
  • Habitat Diversity –different kinds of habitats in an area
  • Species Diversity – has 3 qualities
    • Species Richness: total # of species
    • Species Evenness: relative abundance
    • Species Dominance: most abundant
slide8

Ch.7

Unit 3 – Life on Earth (Ecology) Part 2

(10)

(10)

  • Species Richness: total # of species
  • Species Evenness: relative abundance
  • Species Dominance: most abundant

(0.82)

(0.1)

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Ch.7

Unit 3 – Life on Earth (Ecology) Part 2

Factors that Influence Biodiversity

(see p.133 Table 7.2)

  • Increase:
  • Habitat diversity
  • Few natural disasters
  • Little variation in climate and nutrient supply
  • Species richness at each trophic level
  • Environment highly modified by life (rich organic soil)
  • Middle stages of ecological succession
  • Evolution
  • Decrease:
  • Environmental Stress
  • Extreme environments
  • Nutrient limitations
  • Recent introduction from introduced species
  • Geographic Isolation
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Ch.8

Unit 3 – Life on Earth (Ecology) Part 2

Biogeography

Sustaining Biodiversity

Rule of climactic similarity

Similar physical environments leads to the evolution of organisms similar in form & function

Leads to the concept of BIOMES

  • but with different genetic heritages
  • Convergent Evolution
  • (closely resemble – distantly related)

Defined by similar climate, soil, plants and animals

Climate is determined by latitude and elevation

slide11

Ch.8

Unit 3 – Life on Earth (Ecology) Part 2

Here you can see the relationship between precipitation and latitude.

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Ch.8

Unit 3 – Life on Earth (Ecology) Part 2

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Ch.8

Unit 3 – Life on Earth (Ecology) Part 2

Resistance is the term describing an ecosystem’s ability

to maintain its structural and functional attributes

in the face of stress and disturbances. Resilience

is the ability of an ecosystem to regain structural and

functional attributes that have suffered harm from

stress or disturbance. Ecosystem stability is the ability

of an ecosystem to maintain its given trajectory

in spite of stress; it denotes dynamic equilibrium

rather than stasis. Stability is achieved in part on the

basis of an ecosystem’s capacity for resistance and

resilience.

Insert Biome Pics here!! (when discussing the coloring sheet)

Insert aquatic layers/info

include resilience & inertia in biomes

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Ch.8

Unit 3 – Life on Earth (Ecology) Part 2

Aquatic Biomes

  • Life in Layers
  • Life in most aquatic systems is found in surface, middle, and bottom layers.
  • Temperature, access to sunlight for photosynthesis, dissolved oxygen content, nutrient availability changes with depth.

Scientists estimate that marine systems provide $21 trillion in goods and services per year – 70% more than terrestrial ecosystems

Euphotic zone (upper layer in deep water habitats): sunlight can penetrate.

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Ch.8

Unit 3 – Life on Earth (Ecology) Part 2

The Coastal Zone

  • Where the action is
  • From the high-tide line to the continental shelf
  • Warm, nutrient-rich, shallow water
  • Makes up 10% of the world’s ocean area, but contains 90% of marine species
  • Subject to human disturbances

Continue with aquatics from the miller ch6.

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Ch.8

Unit 3 – Life on Earth (Ecology) Part 2

Island Biogeography

Sustaining Biodiversity

  • Theory of Island Biogeography
    • Islands have fewer species than continents
    • The smaller the island, the fewer the species
  • Adaptive Radiation:
    • The process that occurs when a species enters a new habitat that has unoccupied niches and evolves into a group of new species, each adapted to one of these niches.
  • Ecological Island:
    • An area that is biologically isolated so that a species occurring within the area rarely mixes with any other population of the same species
    • (can be an actual island or it can be a habitat located some distance away from other similar habitats such as a city park located several miles from the closest forest)
slide17

Ch.8

Unit 3 – Life on Earth (Ecology) Part 2

Explain this diagram in terms of immigration, population & extinction.

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Ch.9

Unit 3 – Life on Earth (Ecology) Part 2

No Way!!

Could a frog just survive on mosquitoes that just survive on him?

Because of the natural laws of thermodynamics

1st – Law of conservation of energy (Energy cannot be created nor destroyed)

2nd – Entropy Law – (Energy always changes from a more useful, organized form to less useful disorganized form.)

Energy Efficiency: Measure of how much useful work gets done before it changes to its next form

No system is 100% efficient

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Ch.9

Unit 3 – Life on Earth (Ecology) Part 2

Systems only go SPONTANEOUSLY in the direction of increasing entropy (Lower potential energy)

A system requires an energy input to increase potential energy

&

The energy input is always greater than the energy output

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Ch.9

Unit 3 – Life on Earth (Ecology) Part 2

Organic molecules (biomass) created through photosynthesis have high potential energy

The C-C and C-H bonds found in glucose have more potential energy than the H-O and C-O bonds of water and carbon dioxide

Inorganic molecules released through cellular respiration have low potential energy

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Ch.9

Unit 3 – Life on Earth (Ecology) Part 2

Energy Flow Through an Ecosystem

Trophic level

efficiency is low

(3-10%)

2nd law of Thermodynamics puts a considerable natural limit on biodiversity

Numbers & Biomass

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Ch.9

Unit 3 – Life on Earth (Ecology) Part 2

Primary Production

  • The production of biomass and it’s use as a source of energy (called primary production) by autotrophs includes three steps:
  • Gross Production:An organism produces organic matter within it’s body (ex. Proteins & Sugars)
  • It uses some of this new organic matter as a fuel in cellular respiration
  • It stores some of the newly produced organic matter for future use – called Net Production
  • Net Production = Gross Production - Respiration

The

slide23

Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Ecological Restoration:

the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed.

The cause can be

natural or manmade

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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Why should we restore?

To preserve biodiversity

Habitat loss is the leading cause of both species extinction and ecosystem services decline

Utilitarian Justification:

Natural ecosystems provide human society with food, fuel and timber.

Ecosystem services involve the purification of air and water, detoxification and decomposition of wastes, regulation of climate, regeneration of soil fertility, and pollination of crops.

These processes are estimated to be worth trillions of dollars annually

Moral Justification:

For many people biological diversity (biodiversity) has an intrinsic value; humans have a responsibility toward other living things, and obligations to future generations.

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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Prescribed Fire to Reduce Undergrowth Density and Restore Mixed Conifer Forest, Southwest Oregon

Native Vegetation Restoration (Seropédica, Rio De Janeiro, Brazil), Terrabyte

Mine Restoration in New Jersey by Princeton Hydro

GLACIER NATIONAL PARK in B.C., CANADA

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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Ecological Succession: When nature restores itself

Primary Succession:

Secondary Succession:

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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Pioneer Species: The 1st species to colonize an area

  • Producers able to thrive in nutrient poor environments
  • Need to be fast-spreading and fast-reproducing
  • Modify the environment
    • making new soil on land
    • Providing nutrients
    • (decomposition) in water

Primary succession:

Barren Rock – blue-green bacteria, lichen, mosses

Barren Sand – dune grasses

Salt Water – green algae, eel grass

Fresh Water – algae, mosses

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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

General Patterns of Ecological Succession in a Forest Ecosystem (Secondary Succession)

  • Early-successional species:
  • Annual “weeds” (clover dandelion, “Queen Anne’s lace”)
  • Perennial grasses
  • Small shrubs (poison ivy, brambles, honey suckle)
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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

  • Early-successional species:
  • Annual “weeds” (clover dandelion, “Queen Anne’s lace”)
  • Perennial grasses
  • Small shrubs (poison ivy, brambles, honey suckle)
slide30

Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

General Patterns of Ecological Succession in a Forest Ecosystem (Secondary Succession)

  • Early-successional species:
  • Annual “weeds” (clover dandelion, “Queen Anne’s lace”)
  • Perennial grasses
  • Small shrubs (poison ivy, brambles, honey suckle)
  • Mid-successional species:
  • Shade intolerant, fast growing coniferous trees
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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Soft wood forest

  • Mid-successional species:
  • Shade intolerant, fast growing coniferous trees

Mixed wood forest

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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

General Patterns of Ecological Succession in a Forest Ecosystem (Secondary Succession)

  • Early-successional species:
  • Annual “weeds” (clover dandelion, “Queen Anne’s lace”)
  • Perennial grasses
  • Small shrubs (poison ivy, brambles, honey suckle)
  • Mid-successional species:
  • Shade intolerant, fast growing coniferous trees
  • Late-successional species:
  • Shade-tolerant, slow growing deciduous trees
slide33

Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Oaks, Maple, Beech

Hardwood forest

“Climax Community”

  • Late-successional species:
  • Shade-tolerant, slow growing deciduous trees
slide34

Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Community changes during succession

BIOMASS & BIODIVERSITY

Ecosystem changes during succession

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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Patterns of interaction among earlier and later species

  • Facilitation:
  • Early species facilitate the establishment of later species
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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

  • Facilitation:
  • Early species facilitate the establishment of later species

This used to be a pond

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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

Patterns of interaction among earlier and later species

  • Facilitation:
  • Early species facilitate the establishment of later species
  • Interference
  • Thick grasses interfere with the entrance of other plant species
  • Chronic Patchiness
  • Species do not interact and typical succession does not occur
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Ch.10

Unit 3 – Life on Earth (Ecology) Part 2

  • Chronic Patchiness
  • Species do not interact and typical succession does not occur

Contaminated Soil

Desert