Evolution and Biodiversity - PowerPoint PPT Presentation


Title: Evolution and Biodiversity


1
Chapter 4
  • Evolution and Biodiversity

2
Chapter Overview Questions
  • How do scientists account for the development of
    life on earth?
  • What is biological evolution by natural
    selection, and how can it account for the current
    diversity of organisms on the earth?
  • How can geologic processes, climate change and
    catastrophes affect biological evolution?

3
Chapter Overview Questions (contd)
  • What is the future of evolution, and what role
    should humans play in this future?
  • How did we become such a powerful species in a
    short time?

4
Chapter Overview Questions (contd)
  • What is an ecological niche, and how does it help
    a population adapt to changing environmental
    conditions?
  • How do extinction of species and formation of new
    species affect biodiversity?

5
Review4 Principles of Sustainability?
1. 2. 3. 4.
6
Core Case StudyWhy Should We Care about the
American Alligator?
  • Hunters wiped out population to the point of near
    extinction.
  • 1967- classified as endangered
  • 1975- numbers had rebounded
  • 1977- reclassified as threatened

Figure 7-1
7
Core Case StudyWhy Should We Care about the
American Alligator?
  • Alligators have important ecological role.
  • Alligators are a keystone species
  • Influence on ecosystem is much greater than their
    numbers would suggest

Figure 7-1
8
Core Case StudyAmerican Alligator as Keystone
Species
  • Dig deep depressions (gator holes).
  • Hold water during dry spells, serve as refuges
    for aquatic life.
  • Build nesting mounds.
  • provide nesting and feeding sites for birds.
  • Keeps areas of open water free of vegetation
    (swimming paths)
  • Keep gar populations in check

9
Gator Holes
10
Nesting Mounds
11
Keep Waterways Clear
12
Longnose Gar
13
Alligator Gar
14
Core Case StudyEarth The Just-Right, Adaptable
Planet
  • Distance from sun
  • Spins
  • Size- molten mantle, retain atmosphere
  • Stratospheric Ozone
  • (2 billion years)
  • 21 Oxygen
  • (several hundred million years)
  • Biodiversity Sustainability
  • Temp

Figure 4-1
15
Core Case StudyEarth The Just-Right, Adaptable
Planet
  • During the 3.7 billion years since life arose,
    the average surface temperature of the earth has
    remained within the range of 10-20oC.

Figure 4-1
16
Biological Evolution
  • This has led to the variety of species we find on
    the earth today.

Figure 4-2
17
Modern humans (Homo sapiens sapiens) appear about
2 seconds before midnight
Recorded human history begins about 1/4 second
before midnight
Age of mammals
Age of reptiles
Insects and amphibians invade the land
Origin of life (3.6-3.8 billion years ago)
First fossil record of animals
Plants begin invading land
Evolution and expansion of life
Fig. 4-3, p. 84
18
How Do We Know Which Organisms Lived in the Past?
  • Our knowledge about past life comes from
  • fossils
  • cores drilled out of buried ice
  • analysis of protein similarities
  • DNA RNA analysis.

Figure 4-4
19
EVOLUTION, NATURAL SELECTION, AND ADAPTATION
  • Evolution in Seven Words
  • Genes Mutate, Individuals are Selected,
    Populations Evolve

20
Natural selection acts on individuals, but
evolution occurs in populations
  • Three conditions are necessary for biological
    evolution
  • 1. Genetic variability 2. traits must be
    heritable
  • 3. trait must lead to differential reproduction.
  • An adaptive trait is any heritable trait that
    enables an organism to survive through natural
    selection and reproduce better under prevailing
    environmental conditions.

21
EVOLUTION, NATURAL SELECTION, AND ADAPTATION
  • Biological evolution by natural selection
    involves the change in a populations genetic
    makeup through successive generations.
  • With positive selection pressure, advantageous
    traits help individuals to survive long enough to
    have and raise their young.
  • With negative selection pressure, individuals die
    before they can reproduce.

22
EVOLUTION, NATURAL SELECTION, AND ADAPTATION
  • Advantageous traits originate from genetic
    variability.
  • Genetic variability occurs through
  • mutations random changes in the structure or
    number of DNA molecules in a cell that can be
    inherited by offspring.
  • Exposure to mutagens radioactivity, x rays,
    certain chemicals
  • Random mistakes in DNA duplication, or during RNA
    transcription and translation.

23
Limits on Adaptation through Natural Selection
  • A populations ability to adapt to new
    environmental conditions through natural
    selection is limited by its gene pool and how
    fast it can reproduce.
  • Humans have a relatively slow generation time
    (decades) and output ( of young) versus some
    other species.

24
Common Myths about Evolution through Natural
Selection
  • Yes Biological evolution through natural
    selection is about the most descendants.
  • No (Misunderstandings)
  • Survival of the fittest means survival of the
    biggest, fastest, or strongest.
  • Organisms develop certain traits because they
    need them.
  • Species evolve towards genetic perfection.

25
New Species Hybridization
  • New species can arise through hybridization.
  • Occurs when individuals to two distinct species
    crossbreed to produce a fertile offspring.

The red wolf is thought to be a coyote/wolf hybrid
There are also non-fertile hybrids, such as mules.
26
New Species Gene Swapping
  • Some species (mostly microorganisms) can exchange
    genes without sexual reproduction.
  • Horizontal gene transfer

27
BIODIVERSITY
28
Why Should We Care About Biodiversity?
  • Some consider it ethical to care about nature.
  • Biodiversity provides us with
  • Natural Resources (food, water, wood, energy, and
    medicines)
  • Natural Services (air and water purification,
    soil fertility, waste disposal, pest control)
  • Aesthetic pleasure

29
Biodiversity Loss and Species Extinction
Remember HIPPO
  • These are in order
  • H for habitat destruction and degradation
  • I for invasive species
  • P for pollution
  • P for human population growth
  • O for overexploitation

30
ECOLOGICAL NICHES AND ADAPTATION Coastal Georgia
Smooth cordgrass, Spartina alterniflora
Can grow in fresh water
but it doesnt in the wild.
Why not?
31
ECOLOGICAL NICHES AND ADAPTATION
  • Each species in an ecosystem has a specific 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.

32
Species Diversity and Niche Structure Different
Species Playing Different Roles
  • Biological communities differ in the types and
    numbers of species they contain and the
    ecological roles those species play.
  • Species diversity has 2 components
  • species richness the number of different species
    the ecosystem contains
  • species evenness the abundance of individuals
    within each of those species.

33
Species Diversity and Niche Structure
  • Niche structure how many potential ecological
    niches occur, how they resemble or differ, and
    how the species occupying different niches
    interact.
  • Geographic location species diversity is highest
    in the tropics and declines as we move from the
    equator toward the poles.

34
TYPES OF SPECIES
  • Native, nonnative, indicator, keystone, and
    foundation species play different ecological
    roles in communities.
  • Native those that normally live and thrive in a
    particular community.
  • Nonnative species a.k.a. invasive species those
    that migrate, deliberately or accidentally
    introduced into a community.

35
Indicator Species Biological Smoke Alarms
  • Species that serve as early warnings of damage to
    a community or an ecosystem.
  • Canary in a coal mine
  • Presence or absence of trout species because they
    are sensitive to temperature and oxygen levels.
  • Birds- require a range of habitat
  • Lichens- stay in one place and absorb from the
    environment
  • Amphibians- vulnerable at any part of life cycle

36
Case Study Why are Amphibians Vanishing?
  • Frogs serve as indicator species because
    different parts of their life cycles can be
    easily disturbed.

Next
37
Adult frog(3 years)
Young frog
Sperm
Tadpole develops into frog
Sexual Reproduction
Tadpole
Eggs
Fertilized egg development
Egg hatches
Organ formation
Fig. 7-3, p. 147
38
Case Study Why are Amphibians Vanishing?
  • Habitat loss and fragmentation.
  • Prolonged drought.
  • Increases in ultraviolet radiation.
  • Parasites.
  • Viral and Fungal diseases.
  • Overhunting.
  • Air OR water pollution
  • Natural immigration or deliberate introduction of
    nonnative predators and competitors.

39
Keystone Species Major Players
  • Keystone species help determine the types and
    numbers of other species in a community thereby
    helping to sustain it.

Figures 7-4 and 7-5
40
Foundation Species Other Major Players
  • Subset of keystone species category.
  • Foundation species can create and enhance the
    physical habitats to benefit other species in a
    community.
  • Elephants push over, break, or uproot trees,
    creating forest openings promoting grass growth
    for other species to utilize.
  • Alligators making gator holes

41
Generalist and Specialist Species Broad and
Narrow Niches
  • Generalist species tolerate a wide range of
    conditions.
  • Specialist species can only tolerate a narrow
    range of conditions. Exp tiger salamander, giant
    panda

NEXT
42
Specialist species with a narrow niche
Generalist species with a broad niche
Niche separation
Number of individuals
Niche breadth
Region of niche overlap
Resource use
Fig. 4-7, p. 91
43
SPOTLIGHTCockroaches Natures Ultimate Survivors
  • 350 million year old genus
  • 3,500 different species
  • Ultimate generalist
  • Can eat almost anything.
  • Can live and breed almost anywhere.
  • Can withstand massive doses of radiation.

Figure 4-A
44
Specialized Feeding Niches
  • Resource partitioning reduces competition and
    allows sharing of limited resources.

Figure 4-8
45
Resource Partitioning
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
(Birds not drawn to scale)
Fig. 4-8, pp. 90-91
46
Evolutionary Divergence Darwins Finches
  • Each species has a beak specialized to take
    advantage of certain types of food resource.

Next
47
Insect and nectar eaters
Fruit and seed eaters
Greater Koa-finch
Kuai Akialaoa
Amakihi
Kona Grosbeak
Crested Honeycreeper
Akiapolaau
Maui Parrotbill
Apapane
Unknown finch ancestor
Fig. 4-9, p. 91
48
NATURAL SELECTION DRIVEN BY GEOLOGIC PROCESSES,
CLIMATE CHANGE, CATASTROPHES
  • The movement of solid tectonic plates making up
    the earths surface, volcanic eruptions, and
    earthquakes can wipe out existing species and
    help form new ones.
  • The locations of continents and oceanic basins
    influence climate.
  • The movement of continents have allowed species
    to move.

49
225 million years ago
225 million years ago
135 million years ago
65 million years ago
Present
Fig. 4-5, p. 88
50
Climate Change and Natural Selection
  • Changes in climate throughout the earths history
    have shifted where plants and animals can live.

Next
51
18,000 years before present
Northern Hemisphere Ice coverage
Modern day (August)
Note Modern sea ice coverage represents summer
months
Legend
Continental ice
Sea ice
Land above sea level
Fig. 4-6, p. 89
52
SPECIATION, EXTINCTION, AND BIODIVERSITY
  • Speciation A new species can arise when member
    of a population become isolated for a long period
    of time.
  • Due to natural selection over time, the genetic
    makeup changes, preventing them from producing
    fertile offspring with the original population if
    reunited.

53
Catastrophes and Natural Selection
  • Asteroids and meteorites hitting the earth and
    upheavals of the earth from geologic processes
    have wiped out large numbers of species and
    created evolutionary opportunities by natural
    selection of new species.

54
Geographic Isolation
  • can lead to reproductive isolation, which leads
    to divergence of gene pools and speciation.

Figure 4-10
55
Adapted to cold through heavier fur,short ears,
short legs,short nose. White fur matches snow for
camouflage.
Arctic Fox
Northern population
Different environmental conditions lead to
different selective pressures and evolution into
two different species.
Spreads northward and southward and separates
Early fox Population
Adapted to heat through lightweight fur and long
ears, legs, and nose, which give off more heat.
Southern Population
Gray Fox
Fig. 4-10, p. 92
56
Extinction Lights Out
  • Extinction occurs when the population cannot
    adapt to changing environmental conditions.
  • The golden toad of Costa Ricas Monteverde cloud
    forest has become extinct because of changes in
    climate.

Figure 4-11
57
Categorizing Extinction Rates
  • Biologists estimate that 99.9 of all the species
    that ever existed are now extinct.
  • Background extinction- a certain number of
    species disappearing at a slow rate due to
    changes of local environmental conditions
  • Estimate 1-5 species per million per year
  • Mass depletion- rates of extinction above
    background level but not high enough to be
    considered a mass extinction.
  • Mass extinction- a significant rise in extinction
    rate above background level 20-70

58
Effects of Humans on Biodiversity
  • The scientific consensus is that human activities
    are decreasing the earths biodiversity.

Figure 4-13
59
Terrestrial organisms
Silurian
Permian
Jurassic
Devonian
Devonian
Cambrian
Ordovician
Cretaceous
Marine organisms
Pre-cambrian
Carboniferous
Number of families
Quaternary
Tertiary
Millions of years ago
Fig. 4-13, p. 94
60
Species and families experiencing mass
extinction
Bar width represents relative number of living
species
Millions of years ago
Era
Period
Current extinction crisis caused by human
activities. Many species are expected to become
extinct within the next 50100 years.
Extinction
Quaternary
Today
Cenozoic
Tertiary
Extinction
65
Cretaceous up to 80 of ruling reptiles
(dinosaurs) many marine species including
many foraminiferans and mollusks.
Cretaceous
Mesozoic
Jurassic
Triassic 35 of animal families, including many
reptiles and marine mollusks.
Extinction
180
Triassic
Permian 90 of animal families, including over
95 of marine species many trees, amphibians,
most bryozoans and brachiopods, all trilobites.
Extinction
250
Permian
Carboniferous
Extinction
345
Devonian 30 of animal families, including
agnathan and placoderm fishes and many trilobites.
Devonian
Paleozoic
Silurian
Ordovician
Extinction
Ordovician 50 of animal families, including
many trilobites.
500
Cambrian
Fig. 4-12, p. 93
61
GENETIC ENGINEERING AND THE FUTURE OF EVOLUTION
  • We have used artificial selection to change the
    genetic characteristics of populations with
    similar genes through selective breeding.
  • We have used genetic engineering to transfer
    genes from one species to another (gene splicing)
  • Takes half the time and costs less than
    crossbreeding.

Figure 4-15
62
Genetic Engineering Genetically Modified
Organisms (GMO)
  • GMOs use recombinant DNA
  • genes or portions of genes from different
    organisms.

Figure 4-14
63
Case StudySpecies Diversity on Islands
  • MacArthur and Wilson proposed the species
    equilibrium model a.k.a. theory of island
    biogeography in the 1960s.
  • Model projects that at some point the rates of
    immigration and extinction should reach an
    equilibrium based on
  • Island size
  • Distance to nearest mainland

64
THE FUTURE OF EVOLUTION
  • Biologists are learning to rebuild organisms from
    their cell components and to clone organisms.
  • Cloning has lead to high miscarriage rates, rapid
    aging, organ defects.
  • Genetic engineering can help improve human
    condition, but results are not always
    predictable.
  • Currently We do not know where the new gene will
    be located in the DNA molecules structure and
    how that will affect the organism.

65
Biopharming
  • Biopharming is when humans use genetically
    engineered organisms for the production of
    consumables such as
  • Drugs
  • Chemicals
  • Human body parts
  • Which one of these have we not yet mastered?

66
Controversy Over Genetic Engineering
  • There are a number of privacy, ethical, legal and
    environmental issues.
  • Should genetic engineering and development be
    regulated?
  • What are the long-term environmental consequences?

67
Case StudyHow Did We Become Such a Powerful
Species so Quickly?
  • Compared to other species, we lack
  • strength, speed, agility.
  • weapons (claws, fangs), protection (shell).
  • poor hearing and vision.
  • We have thrived as a species because of our
  • opposable thumbs
  • ability to walk upright
  • complex brains (problem solving).

68
Ch 4 Final Thoughts
  • Microevolution- Traits changing in a species
    (e.g.color, fur type, etc.)
  • Industrial Melanism
  • in pepper moths
  • Macroevolution- The development of new species

69
Ch 4 Final Thoughts
  • Gradualism- species change slowly over time at a
    steady rate of change (Darwin was wrong about
    this)
  • Punctuated Equilibrium- Long periods of stability
    punctuated by periods of rapid change, initiated
    by changes in the environment (evolutionary
    biologist Stephen Jay Gould)

70
Ch 4 Final Thoughts
  • Natural Selection happens to individuals, and
    leads to differential reproduction (think about
    the wooly worms lab)
  • Evolution happens to a population over time, and
    is ultimately understood as changes in gene
    frequencies within that population.
  • Leads to microevolution in the short term
  • Leads to macroevolution in the long term

71
Genetic Engineering Genetically Modified
Organisms (GMO)
  • GMOs use recombinant DNA
  • genes or portions of genes from different
    organisms.

Figure 4-14
72
Phase 1 Make Modified Gene
E. coli
Insert modified plasmid into E. coli
Genetically modified plasmid
Cell
Extract Plasmid
Extract DNA
Plasmid
Gene of interest
DNA
Remove plasmid from DNA of E. coli
Identify and remove portion of DNA with desired
trait
Insert extracted (step 2) into plasmid (step 3)
Identify and extract gene with desired trait
Grow in tissue culture to make copies
Fig. 4-14, p. 95
73
Phase 2 Make Transgenic Cell
A. tumefaciens (agrobacterium)
Foreign DNA
E. Coli
Host DNA
Plant cell
Nucleus
Agrobacterium inserts foreign DNA into plant cell
to yield transgenic cell
Transfer plasmid copies to a carrier agrobacterium
Transfer plasmid to surface of microscopic metal
particle
Use gene gun to inject DNA into plant cell
Fig. 4-14, p. 95
74
Phase 3 Grow Genetically Engineered Plant
Transgenic cell from Phase 2
Cell division of transgenic cells
Culture cells to form plantlets
Transfer to soil
Transgenic plants with new traits
Fig. 4-14, p. 95
75
Phase 3 Grow Genetically Engineered Plant
Stepped Art
Fig. 4-14, p. 95
View by Category
About This Presentation
Title:

Evolution and Biodiversity

Description:

Chapter 4 Evolution and Biodiversity – PowerPoint PPT presentation

Number of Views:89
Avg rating:3.0/5.0
Slides: 76
Provided by: you9190
Learn more at: http://flashmedia.glynn.k12.ga.us
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Evolution and Biodiversity


1
Chapter 4
  • Evolution and Biodiversity

2
Chapter Overview Questions
  • How do scientists account for the development of
    life on earth?
  • What is biological evolution by natural
    selection, and how can it account for the current
    diversity of organisms on the earth?
  • How can geologic processes, climate change and
    catastrophes affect biological evolution?

3
Chapter Overview Questions (contd)
  • What is the future of evolution, and what role
    should humans play in this future?
  • How did we become such a powerful species in a
    short time?

4
Chapter Overview Questions (contd)
  • What is an ecological niche, and how does it help
    a population adapt to changing environmental
    conditions?
  • How do extinction of species and formation of new
    species affect biodiversity?

5
Review4 Principles of Sustainability?
1. 2. 3. 4.
6
Core Case StudyWhy Should We Care about the
American Alligator?
  • Hunters wiped out population to the point of near
    extinction.
  • 1967- classified as endangered
  • 1975- numbers had rebounded
  • 1977- reclassified as threatened

Figure 7-1
7
Core Case StudyWhy Should We Care about the
American Alligator?
  • Alligators have important ecological role.
  • Alligators are a keystone species
  • Influence on ecosystem is much greater than their
    numbers would suggest

Figure 7-1
8
Core Case StudyAmerican Alligator as Keystone
Species
  • Dig deep depressions (gator holes).
  • Hold water during dry spells, serve as refuges
    for aquatic life.
  • Build nesting mounds.
  • provide nesting and feeding sites for birds.
  • Keeps areas of open water free of vegetation
    (swimming paths)
  • Keep gar populations in check

9
Gator Holes
10
Nesting Mounds
11
Keep Waterways Clear
12
Longnose Gar
13
Alligator Gar
14
Core Case StudyEarth The Just-Right, Adaptable
Planet
  • Distance from sun
  • Spins
  • Size- molten mantle, retain atmosphere
  • Stratospheric Ozone
  • (2 billion years)
  • 21 Oxygen
  • (several hundred million years)
  • Biodiversity Sustainability
  • Temp

Figure 4-1
15
Core Case StudyEarth The Just-Right, Adaptable
Planet
  • During the 3.7 billion years since life arose,
    the average surface temperature of the earth has
    remained within the range of 10-20oC.

Figure 4-1
16
Biological Evolution
  • This has led to the variety of species we find on
    the earth today.

Figure 4-2
17
Modern humans (Homo sapiens sapiens) appear about
2 seconds before midnight
Recorded human history begins about 1/4 second
before midnight
Age of mammals
Age of reptiles
Insects and amphibians invade the land
Origin of life (3.6-3.8 billion years ago)
First fossil record of animals
Plants begin invading land
Evolution and expansion of life
Fig. 4-3, p. 84
18
How Do We Know Which Organisms Lived in the Past?
  • Our knowledge about past life comes from
  • fossils
  • cores drilled out of buried ice
  • analysis of protein similarities
  • DNA RNA analysis.

Figure 4-4
19
EVOLUTION, NATURAL SELECTION, AND ADAPTATION
  • Evolution in Seven Words
  • Genes Mutate, Individuals are Selected,
    Populations Evolve

20
Natural selection acts on individuals, but
evolution occurs in populations
  • Three conditions are necessary for biological
    evolution
  • 1. Genetic variability 2. traits must be
    heritable
  • 3. trait must lead to differential reproduction.
  • An adaptive trait is any heritable trait that
    enables an organism to survive through natural
    selection and reproduce better under prevailing
    environmental conditions.

21
EVOLUTION, NATURAL SELECTION, AND ADAPTATION
  • Biological evolution by natural selection
    involves the change in a populations genetic
    makeup through successive generations.
  • With positive selection pressure, advantageous
    traits help individuals to survive long enough to
    have and raise their young.
  • With negative selection pressure, individuals die
    before they can reproduce.

22
EVOLUTION, NATURAL SELECTION, AND ADAPTATION
  • Advantageous traits originate from genetic
    variability.
  • Genetic variability occurs through
  • mutations random changes in the structure or
    number of DNA molecules in a cell that can be
    inherited by offspring.
  • Exposure to mutagens radioactivity, x rays,
    certain chemicals
  • Random mistakes in DNA duplication, or during RNA
    transcription and translation.

23
Limits on Adaptation through Natural Selection
  • A populations ability to adapt to new
    environmental conditions through natural
    selection is limited by its gene pool and how
    fast it can reproduce.
  • Humans have a relatively slow generation time
    (decades) and output ( of young) versus some
    other species.

24
Common Myths about Evolution through Natural
Selection
  • Yes Biological evolution through natural
    selection is about the most descendants.
  • No (Misunderstandings)
  • Survival of the fittest means survival of the
    biggest, fastest, or strongest.
  • Organisms develop certain traits because they
    need them.
  • Species evolve towards genetic perfection.

25
New Species Hybridization
  • New species can arise through hybridization.
  • Occurs when individuals to two distinct species
    crossbreed to produce a fertile offspring.

The red wolf is thought to be a coyote/wolf hybrid
There are also non-fertile hybrids, such as mules.
26
New Species Gene Swapping
  • Some species (mostly microorganisms) can exchange
    genes without sexual reproduction.
  • Horizontal gene transfer

27
BIODIVERSITY
28
Why Should We Care About Biodiversity?
  • Some consider it ethical to care about nature.
  • Biodiversity provides us with
  • Natural Resources (food, water, wood, energy, and
    medicines)
  • Natural Services (air and water purification,
    soil fertility, waste disposal, pest control)
  • Aesthetic pleasure

29
Biodiversity Loss and Species Extinction
Remember HIPPO
  • These are in order
  • H for habitat destruction and degradation
  • I for invasive species
  • P for pollution
  • P for human population growth
  • O for overexploitation

30
ECOLOGICAL NICHES AND ADAPTATION Coastal Georgia
Smooth cordgrass, Spartina alterniflora
Can grow in fresh water
but it doesnt in the wild.
Why not?
31
ECOLOGICAL NICHES AND ADAPTATION
  • Each species in an ecosystem has a specific 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.

32
Species Diversity and Niche Structure Different
Species Playing Different Roles
  • Biological communities differ in the types and
    numbers of species they contain and the
    ecological roles those species play.
  • Species diversity has 2 components
  • species richness the number of different species
    the ecosystem contains
  • species evenness the abundance of individuals
    within each of those species.

33
Species Diversity and Niche Structure
  • Niche structure how many potential ecological
    niches occur, how they resemble or differ, and
    how the species occupying different niches
    interact.
  • Geographic location species diversity is highest
    in the tropics and declines as we move from the
    equator toward the poles.

34
TYPES OF SPECIES
  • Native, nonnative, indicator, keystone, and
    foundation species play different ecological
    roles in communities.
  • Native those that normally live and thrive in a
    particular community.
  • Nonnative species a.k.a. invasive species those
    that migrate, deliberately or accidentally
    introduced into a community.

35
Indicator Species Biological Smoke Alarms
  • Species that serve as early warnings of damage to
    a community or an ecosystem.
  • Canary in a coal mine
  • Presence or absence of trout species because they
    are sensitive to temperature and oxygen levels.
  • Birds- require a range of habitat
  • Lichens- stay in one place and absorb from the
    environment
  • Amphibians- vulnerable at any part of life cycle

36
Case Study Why are Amphibians Vanishing?
  • Frogs serve as indicator species because
    different parts of their life cycles can be
    easily disturbed.

Next
37
Adult frog(3 years)
Young frog
Sperm
Tadpole develops into frog
Sexual Reproduction
Tadpole
Eggs
Fertilized egg development
Egg hatches
Organ formation
Fig. 7-3, p. 147
38
Case Study Why are Amphibians Vanishing?
  • Habitat loss and fragmentation.
  • Prolonged drought.
  • Increases in ultraviolet radiation.
  • Parasites.
  • Viral and Fungal diseases.
  • Overhunting.
  • Air OR water pollution
  • Natural immigration or deliberate introduction of
    nonnative predators and competitors.

39
Keystone Species Major Players
  • Keystone species help determine the types and
    numbers of other species in a community thereby
    helping to sustain it.

Figures 7-4 and 7-5
40
Foundation Species Other Major Players
  • Subset of keystone species category.
  • Foundation species can create and enhance the
    physical habitats to benefit other species in a
    community.
  • Elephants push over, break, or uproot trees,
    creating forest openings promoting grass growth
    for other species to utilize.
  • Alligators making gator holes

41
Generalist and Specialist Species Broad and
Narrow Niches
  • Generalist species tolerate a wide range of
    conditions.
  • Specialist species can only tolerate a narrow
    range of conditions. Exp tiger salamander, giant
    panda

NEXT
42
Specialist species with a narrow niche
Generalist species with a broad niche
Niche separation
Number of individuals
Niche breadth
Region of niche overlap
Resource use
Fig. 4-7, p. 91
43
SPOTLIGHTCockroaches Natures Ultimate Survivors
  • 350 million year old genus
  • 3,500 different species
  • Ultimate generalist
  • Can eat almost anything.
  • Can live and breed almost anywhere.
  • Can withstand massive doses of radiation.

Figure 4-A
44
Specialized Feeding Niches
  • Resource partitioning reduces competition and
    allows sharing of limited resources.

Figure 4-8
45
Resource Partitioning
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
(Birds not drawn to scale)
Fig. 4-8, pp. 90-91
46
Evolutionary Divergence Darwins Finches
  • Each species has a beak specialized to take
    advantage of certain types of food resource.

Next
47
Insect and nectar eaters
Fruit and seed eaters
Greater Koa-finch
Kuai Akialaoa
Amakihi
Kona Grosbeak
Crested Honeycreeper
Akiapolaau
Maui Parrotbill
Apapane
Unknown finch ancestor
Fig. 4-9, p. 91
48
NATURAL SELECTION DRIVEN BY GEOLOGIC PROCESSES,
CLIMATE CHANGE, CATASTROPHES
  • The movement of solid tectonic plates making up
    the earths surface, volcanic eruptions, and
    earthquakes can wipe out existing species and
    help form new ones.
  • The locations of continents and oceanic basins
    influence climate.
  • The movement of continents have allowed species
    to move.

49
225 million years ago
225 million years ago
135 million years ago
65 million years ago
Present
Fig. 4-5, p. 88
50
Climate Change and Natural Selection
  • Changes in climate throughout the earths history
    have shifted where plants and animals can live.

Next
51
18,000 years before present
Northern Hemisphere Ice coverage
Modern day (August)
Note Modern sea ice coverage represents summer
months
Legend
Continental ice
Sea ice
Land above sea level
Fig. 4-6, p. 89
52
SPECIATION, EXTINCTION, AND BIODIVERSITY
  • Speciation A new species can arise when member
    of a population become isolated for a long period
    of time.
  • Due to natural selection over time, the genetic
    makeup changes, preventing them from producing
    fertile offspring with the original population if
    reunited.

53
Catastrophes and Natural Selection
  • Asteroids and meteorites hitting the earth and
    upheavals of the earth from geologic processes
    have wiped out large numbers of species and
    created evolutionary opportunities by natural
    selection of new species.

54
Geographic Isolation
  • can lead to reproductive isolation, which leads
    to divergence of gene pools and speciation.

Figure 4-10
55
Adapted to cold through heavier fur,short ears,
short legs,short nose. White fur matches snow for
camouflage.
Arctic Fox
Northern population
Different environmental conditions lead to
different selective pressures and evolution into
two different species.
Spreads northward and southward and separates
Early fox Population
Adapted to heat through lightweight fur and long
ears, legs, and nose, which give off more heat.
Southern Population
Gray Fox
Fig. 4-10, p. 92
56
Extinction Lights Out
  • Extinction occurs when the population cannot
    adapt to changing environmental conditions.
  • The golden toad of Costa Ricas Monteverde cloud
    forest has become extinct because of changes in
    climate.

Figure 4-11
57
Categorizing Extinction Rates
  • Biologists estimate that 99.9 of all the species
    that ever existed are now extinct.
  • Background extinction- a certain number of
    species disappearing at a slow rate due to
    changes of local environmental conditions
  • Estimate 1-5 species per million per year
  • Mass depletion- rates of extinction above
    background level but not high enough to be
    considered a mass extinction.
  • Mass extinction- a significant rise in extinction
    rate above background level 20-70

58
Effects of Humans on Biodiversity
  • The scientific consensus is that human activities
    are decreasing the earths biodiversity.

Figure 4-13
59
Terrestrial organisms
Silurian
Permian
Jurassic
Devonian
Devonian
Cambrian
Ordovician
Cretaceous
Marine organisms
Pre-cambrian
Carboniferous
Number of families
Quaternary
Tertiary
Millions of years ago
Fig. 4-13, p. 94
60
Species and families experiencing mass
extinction
Bar width represents relative number of living
species
Millions of years ago
Era
Period
Current extinction crisis caused by human
activities. Many species are expected to become
extinct within the next 50100 years.
Extinction
Quaternary
Today
Cenozoic
Tertiary
Extinction
65
Cretaceous up to 80 of ruling reptiles
(dinosaurs) many marine species including
many foraminiferans and mollusks.
Cretaceous
Mesozoic
Jurassic
Triassic 35 of animal families, including many
reptiles and marine mollusks.
Extinction
180
Triassic
Permian 90 of animal families, including over
95 of marine species many trees, amphibians,
most bryozoans and brachiopods, all trilobites.
Extinction
250
Permian
Carboniferous
Extinction
345
Devonian 30 of animal families, including
agnathan and placoderm fishes and many trilobites.
Devonian
Paleozoic
Silurian
Ordovician
Extinction
Ordovician 50 of animal families, including
many trilobites.
500
Cambrian
Fig. 4-12, p. 93
61
GENETIC ENGINEERING AND THE FUTURE OF EVOLUTION
  • We have used artificial selection to change the
    genetic characteristics of populations with
    similar genes through selective breeding.
  • We have used genetic engineering to transfer
    genes from one species to another (gene splicing)
  • Takes half the time and costs less than
    crossbreeding.

Figure 4-15
62
Genetic Engineering Genetically Modified
Organisms (GMO)
  • GMOs use recombinant DNA
  • genes or portions of genes from different
    organisms.

Figure 4-14
63
Case StudySpecies Diversity on Islands
  • MacArthur and Wilson proposed the species
    equilibrium model a.k.a. theory of island
    biogeography in the 1960s.
  • Model projects that at some point the rates of
    immigration and extinction should reach an
    equilibrium based on
  • Island size
  • Distance to nearest mainland

64
THE FUTURE OF EVOLUTION
  • Biologists are learning to rebuild organisms from
    their cell components and to clone organisms.
  • Cloning has lead to high miscarriage rates, rapid
    aging, organ defects.
  • Genetic engineering can help improve human
    condition, but results are not always
    predictable.
  • Currently We do not know where the new gene will
    be located in the DNA molecules structure and
    how that will affect the organism.

65
Biopharming
  • Biopharming is when humans use genetically
    engineered organisms for the production of
    consumables such as
  • Drugs
  • Chemicals
  • Human body parts
  • Which one of these have we not yet mastered?

66
Controversy Over Genetic Engineering
  • There are a number of privacy, ethical, legal and
    environmental issues.
  • Should genetic engineering and development be
    regulated?
  • What are the long-term environmental consequences?

67
Case StudyHow Did We Become Such a Powerful
Species so Quickly?
  • Compared to other species, we lack
  • strength, speed, agility.
  • weapons (claws, fangs), protection (shell).
  • poor hearing and vision.
  • We have thrived as a species because of our
  • opposable thumbs
  • ability to walk upright
  • complex brains (problem solving).

68
Ch 4 Final Thoughts
  • Microevolution- Traits changing in a species
    (e.g.color, fur type, etc.)
  • Industrial Melanism
  • in pepper moths
  • Macroevolution- The development of new species

69
Ch 4 Final Thoughts
  • Gradualism- species change slowly over time at a
    steady rate of change (Darwin was wrong about
    this)
  • Punctuated Equilibrium- Long periods of stability
    punctuated by periods of rapid change, initiated
    by changes in the environment (evolutionary
    biologist Stephen Jay Gould)

70
Ch 4 Final Thoughts
  • Natural Selection happens to individuals, and
    leads to differential reproduction (think about
    the wooly worms lab)
  • Evolution happens to a population over time, and
    is ultimately understood as changes in gene
    frequencies within that population.
  • Leads to microevolution in the short term
  • Leads to macroevolution in the long term

71
Genetic Engineering Genetically Modified
Organisms (GMO)
  • GMOs use recombinant DNA
  • genes or portions of genes from different
    organisms.

Figure 4-14
72
Phase 1 Make Modified Gene
E. coli
Insert modified plasmid into E. coli
Genetically modified plasmid
Cell
Extract Plasmid
Extract DNA
Plasmid
Gene of interest
DNA
Remove plasmid from DNA of E. coli
Identify and remove portion of DNA with desired
trait
Insert extracted (step 2) into plasmid (step 3)
Identify and extract gene with desired trait
Grow in tissue culture to make copies
Fig. 4-14, p. 95
73
Phase 2 Make Transgenic Cell
A. tumefaciens (agrobacterium)
Foreign DNA
E. Coli
Host DNA
Plant cell
Nucleus
Agrobacterium inserts foreign DNA into plant cell
to yield transgenic cell
Transfer plasmid copies to a carrier agrobacterium
Transfer plasmid to surface of microscopic metal
particle
Use gene gun to inject DNA into plant cell
Fig. 4-14, p. 95
74
Phase 3 Grow Genetically Engineered Plant
Transgenic cell from Phase 2
Cell division of transgenic cells
Culture cells to form plantlets
Transfer to soil
Transgenic plants with new traits
Fig. 4-14, p. 95
75
Phase 3 Grow Genetically Engineered Plant
Stepped Art
Fig. 4-14, p. 95
About PowerShow.com