Biodiversity and Evolution Chapter 4

The American Alligator, worth saving?

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

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

Four Scientific Principles of Sustainability 5

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.

What does biodiversity mean to you?

Natural Capital: Major Components of the Earth’s Biodiversity

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

Biodiversity Is a Crucial Part of the Earth’s 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

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?

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).

What does Evolution mean to you? Do you think it happens? Evidence?

What do these pictures have in common?

Biological Evolution by Natural Selection Explains How Life Changes over Time 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

What is the tree of life?

Six Major Kingdoms of Species as a Result of Natural Selection

Prokaryotes Eukaryotes Eubacteria Archaebacteria Protists Plants Fungi Animals Cenozoic First humans 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 Figure 4.3 Overview of the evolution of life on the earth into six major kingdoms of species as a result of natural selection. For more details, see p. S46 in Supplement 7. 3,000 3,500 Oldest prokaryotic fossils 4,000 Earth cool enough for crust to solidify 4,500 Origin of Earth Fig. 4-3, p. 81

Animation: Evolutionary tree of life

Animation: Evolutionary tree diagrams

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?

Fossilized Skeleton of an Herbivore that Lived during the Cenozoic Era

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.

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

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

A group of bacteria, including genetically resistant ones, are exposed to an antibiotic Normal bacterium Resistant bacterium Eventually the resistant strain replaces the strain affected by the antibiotic The genetically resistant bacteria start multiplying Most of the normal bacteria die Figure 4.5 Evolution by natural selection. (a) A population of bacteria is exposed to an antibiotic, which (b) kills all but those possessing a trait that makes them resistant to the drug. (c) The resistant bacteria multiply and eventually (d) replace the nonresistant bacteria. Stepped Art Fig. 4-5, p. 83

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?

Case Study: How Did Humans Become Such a Powerful Species? Three human adaptations Strong opposable thumbs Walk upright Complex brain

Adaptation through Natural Selection Has Limits Genetic change must precede change in the environmental conditions Reproductive capacity How many How fast

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

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?

Charles Darwin 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 being evolved

Evolution Timeline Project/Lab

Video: Creation vs. evolution

Animation: Disruptive selection

Animation: Change in moth population

Animation: Stabilizing selection

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.

What drives evolution?

What determines the amount of resources?

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

225 million years ago 135 million years ago 65 million years ago Present Figure 4.6 Over millions of years, the earth’s continents have moved very slowly on several gigantic tectonic plates. This process plays a role in the extinction of species, as land areas split apart, and also in the rise of new species when isolated land areas combine. Rock and fossil evidence indicates that 200–250 million years ago, all of the earth’s present-day continents were locked together in a supercontinent called Pangaea (top left). About 180 million years ago, Pangaea began splitting apart as the earth’s tectonic plates separated, eventually resulting in today’s locations of the continents (bottom right). Question: How might an area of land splitting apart cause the extinction of a species? Stepped Art Fig. 4-6, p. 85

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

Changes in Ice Coverage in the Northern Hemisphere During the last 18,000 Years

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)

Animation: Stanley Miller's experiment

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?

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 earth’s 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.

Evolution Through geographic isolation Through reproductive 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

Geographic Isolation Can Lead to Reproductive Isolation

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

Animation: Speciation on an archipelago

Extinction is Forever Extinction Endemic species Background 1:5,000,000 Mass >25% 3-5 events in history with mass extinction and low speciation Endemic species Specialized Found in only one location Particularly vulnerable

Golden Toad of Costa Rica, Extinct

Genetic engineering, gene splicing Consider 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

Genetically Engineered Mice

Animation: Transferring genes into plants

Video: Cloned pooch

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?

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.

Evolution Through geographic isolation Through reproductive 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

Species Diversity: Variety, Abundance of Species in a Particular Place 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

Variations in Species Richness

Variation in species evenness Temperate Forest, African Savannah, Canadian Aspen forest

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

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

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

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 roles—native, nonnative, indicator, keystone, or foundation roles—in a particular ecosystem.

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

Specialist Species and Generalist Species Niches

Case Study: Cockroaches: Nature’s Ultimate Survivors 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

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 Brown pelican dives for fish, which it locates from the air Herring gull is a tireless scavenger 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 Figure 4.13 Specialized feeding niches of various bird species in a coastal wetland. This specialization reduces competition and allows sharing of limited resources. Fig. 4-13, p. 93

Niches Can Be Occupied by Native and Nonnative Species Nonnative species; invasive, alien, or exotic species May spread rapidly Not all are villains (farm- commercial animals) All disturb the existing ecosystem

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

Indicator Species Serve as Biological Smoke Alarms Can monitor environmental quality Trout (need clean highly oxygenated water) Birds (fragmentation, pesticides) Butterflies (fragmentation, species loss) Frogs (next slide)

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

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

Life Cycle of a Frog Adult frog (3 years) Young frog Sperm Tadpole develops into frog Sexual reproduction Tadpole Figure 4.14 Life cycle of a frog. Populations of various frog species can decline because of the effects of harmful factors at different points in their life cycle. Such factors include habitat loss, drought, pollution, increased ultraviolet radiation, parasitism, disease, overhunting by humans, and nonnative predators and competitors. Eggs Fertilized egg development Egg hatches Organ formation Fig. 4-14, p. 94

What is a keystone?

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)

Keystone and foundation species play similar role in building and maintaining an healthy ecosystem

Why should we protect sharks?

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

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

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

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 ?