Title: Biodiversity and Evolution
1Biodiversity and Evolution
2The American Alligator, worth saving?
3Core 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
4Why 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
5Four Scientific Principles of Sustainability
64-1 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.
7What does biodiversity mean to you?
8Natural Capital Major Components of the Earths
Biodiversity
9Different 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
10Biodiversity 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
11Questions 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?
124-2 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).
13What does Evolution mean to you?
- Do you think it happens?
- Evidence?
14What do these pictures have in common?
15Biological 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
16What is the tree of life?
17Six Major Kingdoms of Species as a Result of
Natural Selection
18Prokaryotes
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
19Animation Evolutionary tree of life
20Animation Evolutionary tree diagrams
21The 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?
22Fossilized Skeleton of an Herbivore that Lived
during the Cenozoic Era
23The 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.
24Answer
- Can a fish species willfully grow limbs and
fingers if they are needed to crawl out of the
water onto dry land?
25Individuals 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
26Stepped Art
Fig. 4-5, p. 83
27Humans 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?
28Case Study How Did Humans Become Such a Powerful
Species?
- Three human adaptations
- Strong opposable thumbs
- Walk upright
- Complex brain
29Adaptation through Natural Selection Has Limits
- Genetic change must precede change in the
environmental conditions - Reproductive capacity
- How many
- How fast
30Three 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
31Questions 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?
32There 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
33Evolution Timeline Project/Lab
34Video Creation vs. evolution
35Animation Disruptive selection
36Animation Change in moth population
37Animation Stabilizing selection
384-3 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.
39What drives evolution?
40What determines the amount of resources?
41Geologic 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
42Stepped Art
Fig. 4-6, p. 85
43Climate 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
44Changes in Ice Coverage in the Northern
Hemisphere During the last 18,000 Years
45Science 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)
46Animation Stanley Miller's experiment
47Questions 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?
484-4 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.
49Evolution
- 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
50Geographic Isolation Can Lead to Reproductive
Isolation
51Speciation
- Two species arise from one
- Environments change for 2 groups of same species
- Change progresses to point where breeding
produces sterile offspring
52Animation Speciation on an archipelago
53Extinction 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
54Golden Toad of Costa Rica, Extinct
55Science 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
56Genetically Engineered Mice
57Animation Transferring genes into plants
58Video Cloned pooch
59Exit 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?
604-5 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.
61Evolution
- 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
62Species 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
63Variations in Species Richness
64Variation in species evenness
- Temperate Forest, African Savannah, Canadian
Aspen forest
65Science 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
66Species-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
67Questions 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
684-6 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.
69Each 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
70Specialist Species and Generalist Species Niches
71Case 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
72Specialized 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
73Niches 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
74Killer 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
75Indicator 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)
76Case 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
77Case 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
78Adult 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
79What is a keystone?
80Keystone, 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)
81Keystone and foundation species play similar role
in building and maintaining an healthy ecosystem
82Why should we protect sharks?
83Case 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
844.6
- Q20) Distinguish between native, invasive,
indicator, keystone and foundation species - Q21) Distinguish between specialist species and
generalist species.
85Writing assignment
- Critical thinking questions 7, 8 on pg 98
- Use ideas discussed in this or other chapters to
fortify your answer to the questions
86UN 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 ?