Biodiversity and Evolution

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Biodiversity and Evolution

• Chapter 4

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The American Alligator, worth saving?
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Core Case Study Why Should We Care about the
American Alligator?

• Largest reptile in North America
• 1930s Hunters and poachers (sport, bellies,
  meat)
• 90 killed off
• 1967 endangered species
• 1977 comeback, threatened species

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Why are alligators important?

• Keystone species
• Presence in food web Gar, eggs, small gators
• Gator holes- dug out, freshwater, drought
• Nesting mounds, used by other animals
• Pathways- keep waterways open, hold back changes
  in swamp
• Medicine blood kills certain types of bacteria,
  antibodies that destroy drug resistant varieties

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Four Scientific Principles of Sustainability
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4-1 What Is Biodiversity and Why Is It Important?

• Concept 4-1 The biodiversity found in genes,
  species, ecosystems, and ecosystem processes is
  vital to sustaining life on earth.

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What does biodiversity mean to you?
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Natural Capital Major Components of the Earths
Biodiversity
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Different types of diversity

• Species diversity the number and abundance of
  species present in different communities
• Ecosystem diversity The variety of ecosystems,
  aquatic environments found in a place or on earth
• Functional diversity variety in the processes
  and energy flow in an ecosystem extra uses of
  nests, paths of gators
• Genetic Diversity Variety in traits, genetic
  material found within a certain species

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Biodiversity Is a Crucial Part of the Earths
Natural Capital

• Vital renewable resources
• Variety of food found in all ecosystems
• Wood, fibers, energy, medicine
• Waste and pest control
• Air and water quality (regulation of ecosystem
  health

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Questions on 4.1

• Q2 What are three ways that the American
  alligator supports one or more of the four
  components of biodiversity within its
  environment?
• Q3 What are three examples of how people, in
  their daily living, intentionally or
  unintentionally degrade each of these types of
  biodiversity?
• Q4 What are the main differences between
  Functional and Ecological Diversity? What are
  the main differences between species and genetic
  diversity?
• Q5 Why is having a lot of biodiversity on earth
  so beneficial to us?

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4-2 Where Do Species Come From?

• Concept 4-2A The scientific theory of evolution
  explains how life on earth changes over time
  through changes in the genes of populations.
• Concept 4-2B Populations evolve when genes
  mutate and give some individuals genetic traits
  that enhance their abilities to survive and to
  produce offspring with these traits (natural
  selection).

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What does Evolution mean to you?

• Do you think it happens?
• Evidence?

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What do these pictures have in common?
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Biological Evolution by Natural Selection
Explains How Life Changes over Time

• Natural selection
• Constant struggle for food, resources to survive
• Some individuals have advantage over others
• Those with tend to have more successful offspring
  
• Charles Darwin
• (gathered evidence AND published)
• Alfred Russell Wallace

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What is the tree of life?
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Six Major Kingdoms of Species as a Result of
Natural Selection
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Prokaryotes
Eukaryotes
Plants
Eubacteria
Animals
Fungi
Archaebacteria
Protists
0
First humans
Cenozoic
Mesozoic
Extinction of dinosaurs
Plants colonize land
Paleozoic
500
Origin of multicellular organisms
1,000
1,500
Oldest eukaryotic fossils
2,000
Millions of years ago
Accumulation of O2 in atmosphere from
photosynthetic cyanobacterium
2,500
Precambrian
3,000
Oldest prokaryotic fossils
3,500
4,000
Earth cool enough for crust to solidify
Origin of Earth
4,500
Fig. 4-3, p. 81
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Animation Evolutionary tree of life
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Animation Evolutionary tree diagrams
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The Fossil Record Tells Much of the Story of
Evolution

• Fossils
• Physical evidence of ancient organisms
• Bones, casts, tracks
• Some reveal what their internal structures looked
  like, some their actions
• How many species leave fossils?
• Have all fossils been discovered?

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Fossilized Skeleton of an Herbivore that Lived
during the Cenozoic Era
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The Genetic Makeup of a Population Can Change

• Populations evolve by becoming genetically
  different
• Genetic variations
• First step in biological evolution
• Occurs through mutations in reproductive cells
• Mutations in other cells can happen , but only
  reproductive cell mutations are passed on
• Sometimes a mutation can result in a new genetic
  trait that gives it a better chance to survive,
  sometimes not.

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Answer

• Can a fish species willfully grow limbs and
  fingers if they are needed to crawl out of the
  water onto dry land?

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Individuals in Populations with Beneficial
Genetic Traits Can Leave More Offspring

• Natural selection acts on individuals
• Second step in biological evolution
• Adaptation may lead to differential reproduction
• Genetic resistance in bacteria, cockroaches
• When environmental conditions change, populations
• Adapt
• Migrate
• Become extinct

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Stepped Art
Fig. 4-5, p. 83
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Humans and Natural Selection

• Is it still going on? Evidence
• Traits that might lead to differential production
• Do the number of offspring matter for human
  adaptation?

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Case Study How Did Humans Become Such a Powerful
Species?

• Three human adaptations
• Strong opposable thumbs
• Walk upright
• Complex brain

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Adaptation through Natural Selection Has Limits

• Genetic change must precede change in the
  environmental conditions
• Reproductive capacity
• How many
• How fast

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Three Common Myths about Evolution through
Natural Selection

• Survival of the fittest is not survival of the
  strongest
• Organisms do not develop traits out of need or
  want
• No grand plan of nature for perfect adaptation

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Questions on 4.2

• Q1) Some people are born with 6 fingers or webbed
  toes. The above named features are examples of
  what biological concepts?
• Q2) Do the features listed in Q1 have impact on
  the natural selection process of humans? Explain
• Q3) Why does the tree of life have branches?

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There is a grandeur to this view of life
(evolution) While this planet has gone cycling
on Endless forms most beautiful and wonderful
have been and are beingevolved

• Charles Darwin

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Evolution Timeline Project/Lab
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Video Creation vs. evolution
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Animation Disruptive selection
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Animation Change in moth population
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Animation Stabilizing selection
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4-3 How Do Geological Processes and Climate
Change Affect Evolution?

• Concept 4-3 Tectonic plate movements, volcanic
  eruptions, earthquakes, and climate change have
  shifted wildlife habitats, wiped out large
  numbers of species, and created opportunities for
  the evolution of new species.

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What drives evolution?
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What determines the amount of resources?
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Geologic Processes Affect Natural Selection

• Tectonic plates affect evolution and the location
  of life on earth
• Location of continents and oceans
• Species physically move, or adapt, or form new
  species through natural selection
• Tectonic actions Earthquakes, Volcanic eruptions
  can have profound effects on natural selection
• Pollution
• Change in ecosystem

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Stepped Art
Fig. 4-6, p. 85
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Climate Change and Catastrophes Affect Natural
Selection

• Ice ages followed by warming temperatures
• Demise of the giants (sloth, Saber tooth tigers)
• Collisions between the earth and large asteroids
• New species
• Extinction

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Changes in Ice Coverage in the Northern
Hemisphere During the last 18,000 Years
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Science Focus Earth Is Just Right for Life to
Thrive

• Certain temperature range (closeness to sun)
• Dependence on water
• Rotation on its axis (how fast or slow we spin)
• Revolution around the sun (changes in season)
• Enough gravitational mass (to hold on to the
  atmo)

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Animation Stanley Miller's experiment
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Questions on 4.3

• Q1) What is the connection between the
  environment and evolution?
• Q2) Will humans evolve to a point where we can
  survive in space without a spacesuit or any
  protective device? Why or Why not?
• Q3) how does pollution effect evolution?

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4-4 How Do Speciation, Extinction, and Human
Activities Affect Biodiversity?

• Concept 4-4A As environmental conditions change,
  the balance between formation of new species and
  extinction of existing species determines the
  earths biodiversity.
• Concept 4-4B Human activities can decrease
  biodiversity by causing the premature extinction
  of species and by destroying or degrading
  habitats needed for the development of new
  species.

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Evolution

• Through geographic isolation
• Groups of same species become physically isolated
• Migration, physical barriers (volcanoes to roads)
• Through reproductive isolation
• Mutation and change by natural selection occur in
  isolated geographic populations long enough
• New species when interbreeding produces
  onlysterile offspring

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Geographic Isolation Can Lead to Reproductive
Isolation
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Speciation

• Two species arise from one
• Environments change for 2 groups of same species
• Change progresses to point where breeding
  produces sterile offspring

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Animation Speciation on an archipelago
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Extinction is Forever

• Extinction
• Background 15,000,000
• Mass gt25
• 3-5 events in history with mass extinction and
  low speciation
• Endemic species
• Specialized
• Found in only one location
• Particularly vulnerable

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Golden Toad of Costa Rica, Extinct
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Science Focus Humans Have Two Ways to Change the
Genetic Traits of Populations

• Artificial selection
• Genetic engineering, gene splicing
• Consider
• Ethics
• Morals
• Privacy issues
• Harmful effects

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Genetically Engineered Mice
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Animation Transferring genes into plants
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Video Cloned pooch
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Exit questions

• Q10 Distinguish between geographic isolation and
  reproductive isolation.
• Q11 Distinguish between artificial selection and
  genetic engineering (gene splicing)
• Q12 Distinguish between background extinction and
  mass extinction?

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4-5 What Is Species Diversity and Why Is It
Important?

• Concept 4-5 Species diversity is a major
  component of biodiversity and tends to increase
  the sustainability of ecosystems.

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Evolution

• Through geographic isolation
• Groups of same species become physically isolated
• Migration, physical barriers (volcanoes to roads)
• Through reproductive isolation
• Mutation and change by natural selection occur in
  isolated geographic populations long enough
• New species when interbreeding produces
  onlysterile offspring

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Species Diversity Variety, Abundance of Species
in a Particular Place

• Species diversity
• Species richness (diversity in species)
• Species evenness (abundance of each species)
• Diversity varies with geographical location
• Most species-rich communities
• Tropical rain forests
• Coral reefs
• Ocean bottom zone
• Large tropical lakes

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Variations in Species Richness
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Variation in species evenness

• Temperate Forest, African Savannah, Canadian
  Aspen forest

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Science Focus Species Richness on Islands

• Species equilibrium model
• Theory of island biogeography
• Rate of new species immigrating should balance
  with the rate of species extinction
• Island size and distance from the mainland need
  to be considered
• Larger and closer is more species rich

Island ? isolated region
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Species-Rich Ecosystems Tend to Be Productive and
Sustainable

• Species richness seems to increase productivity
  and stability or sustainability of a location
• More diverse ecosystem, more productive, greater
  biomass
• More diverse, more complex web, more resistant
  to environmental disturbances
• Only a hypothesis, more study is needed

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Questions on 4.5

• Q15) Distinguish between species richness and
  evenness
• Q16) Suppose we have 2 national parks close to
  each other surrounded by development. One is a
  large park and the other much smaller. Which
  park is likely to have the highest species
  richness? Why?
• Q17) Explain why species rich ecosystems tend to
  be productive and sustainable

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4-6 What Roles Do Species Play in Ecosystems?

• Concept 4-6A Each species plays a specific
  ecological role called its niche.
• Concept 4-6B Any given species may play one or
  more of five important rolesnative, nonnative,
  indicator, keystone, or foundation rolesin a
  particular ecosystem.

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Each Species Plays a Unique Role in Its Ecosystem

• Ecological niche
• Pattern of living, species way of life and
  includes everything that affects survival and
  reproduction
• Generalist species (mice, humans, raccoons)
• Broad niche
• Specialist species
• (Tiger salamanders, pandas)
• Narrow niche

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Specialist Species and Generalist Species Niches
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Case Study Cockroaches Natures Ultimate
Survivors

• Cockroaches
• Generalists
• High reproductive rates
• 10 million annually
• Eat almost anything
• Finger nail clippings, electric cords, soap
• Live and breed in all but arctic environ
• Antennae, knee joints, eyes
• Sample food-avoid poison

Good food for higher order consumers
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Specialized Feeding Niches of Various Bird
Species in a Coastal Wetland
Ruddy turnstone searches under shells and
pebbles for small invertebrates
Dowitcher probes deeply into mud in search of
snails, marine worms, and small crustaceans
Black skimmer seizes small fish at water
surface Black skimmer seizes small fish at water
surface
Herring gull is a tireless scavenger
Brown pelican dives for fish, which it locates
from the air
Avocet sweeps bill through mud and surface water
in search of small crustaceans, insects, and seeds
Flamingo feeds on minute organisms in mud
Scaup and other diving ducks feed on mollusks,
crustaceans, and aquatic vegetation
Louisiana heron wades into water to seize small
fish
Oystercatcher feeds on clams, mussels, and other
shellfish into which it pries its narrow beak
Knot (sandpiper) picks up worms and small
crustaceans left by receding tide
Piping plover feeds on insects and
tiny crustaceans on sandy beaches
Fig. 4-13, p. 93
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Niches Can Be Occupied by Native and Nonnative
Species

• Native species
• Nonnative species invasive, alien, or exotic
  species
• May spread rapidly
• Not all are villains (farm- commercial animals)
• All disturb the existing ecosystem

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Killer Bees

• 1957, Brazil to increase honey production
• Instead killed off native bee population
• Been migrating North every since
• Not terror movie life, but more aggressive and
  unpredictable

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Indicator Species Serve as Biological Smoke Alarms

• Indicator species
• Can monitor environmental quality
• Trout (need clean highly oxygenated water)
• Birds (fragmentation, pesticides)
• Butterflies (fragmentation, species loss)
• Frogs (next slide)

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Case Study Why Are Amphibians Vanishing? (1)

• Habitat loss and fragmentation
• Prolonged drought
• Pollution
• Increase in UV radiation
• Parasites (worms causing increase in birth
  defects)
• Viral and fungal diseases
• Climate change (2005 and 2008 studies)
• Overhunting (Asia and France)
• Nonnative predators and competitors

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Case Study Why Are Amphibians Vanishing? (2)

• Importance of amphibians
• Sensitive biological indicators of environmental
  changes
• Adult amphibians
• Important ecological roles in biological
  communities
• Genetic storehouse of pharmaceutical products
  waiting to be discovered

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Adult frog (3 years)
Young frog
Life Cycle of a Frog
Sperm
Tadpole develops into frog
Sexual reproduction
Tadpole
Eggs
Fertilized egg development
Egg hatches
Organ formation
Fig. 4-14, p. 94
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What is a keystone?
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Keystone, Foundation Species Determine Structure,
Function of Their Ecosystems

• Keystone species
• Pollinators
• Top predator
• Loss of keystone species lead to population
  crashes of other species in ecosystem
• Foundation species
• Create or enhance their habitats, which benefit
  others
• Elephants (trails)
• Beavers (build wetlands)

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Keystone and foundation species play similar role
in building and maintaining an healthy ecosystem
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Why should we protect sharks?
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Case Study Why Should We Protect Sharks?

• Keystone species
• Eat dead and dying fish in the ocean
• Control other populations
• Strong immune systems
• Wounds do not get infected
• Almost never get cancer
• Could help humans if we understood their immune
  system

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4.6

• Q20) Distinguish between native, invasive,
  indicator, keystone and foundation species
• Q21) Distinguish between specialist species and
  generalist species.

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Writing assignment

• Critical thinking questions 7, 8 on pg 98
• Use ideas discussed in this or other chapters to
  fortify your answer to the questions

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UN Project Questions

• Are there regions of your country with large
  amounts of biodiversity?
• What climate conditions/Geologic features have
  influence natural selection in the major biomes
  of your country
• Indicate some unique indicator, keystone,
  foundation, invasive and specialist species that
  live within the borders of your country
• Does the people in your country get most of their
  food from within ?