Evolution and Biodiversity Chapter 4

Core Case Study: Life on Earth  Uniquely suited for life Temperature range Liquid water Gravitational mass Oxygen  Organisms contribute to relatively consistent planetary conditions – resilient and adaptive  Biodiversity and sustainability

The Right Mix of Conditions Fig. 4-1, p. 63

4-1 What Is Biological Evolution and How Does It Occur?  Concept 4-1A The scientific theory of evolution explains how life on earth changes over time through changes in the genes of populations.  Concept 4-1B 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).

Theory of Evolution  4.7 billion years  Explains why life so diverse  Supported by fossils, chemical analysis of primitive rock, DNA, and ice cores

Fossilized Skeleton of a Cenozoic Herbivore Fig. 4-2, p. 65

Population Changes over Time  Populations evolve by becoming genetically different  Genetic variability – mutation

Natural Selection  Genetically favorable traits to survive and reproduce  Trait – heritable and lead to differential reproduction  Faced with environmental change Adapt Migrate Become extinct

Coevolution  Changes in gene pool of one species lead to changes in gene pool of the other  Bats and moths

Science Focus: How Did We Become Such a Powerful Species?  Key adaptations – also enabled us to modify environment  Evolved very recently  Technology dominates earth’s life support systems and NPP

4-2 How Do Geological and Climate Changes Affect Evolution?  Concept 4-2 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.

Plate Tectonics  Locations of continents and oceans determine earth’s climate  Movement of continents allow species to move and adapt  Earthquakes and volcanoes affect biological evolution

Movement of Continents

Fig. 4-3, p. 67 Present 65 million years ago 135 million years ago 225 million years ago

Present 225 million years ago 65 million years ago 135 million years ago Fig. 4-3, p. 67 Stepped Art

Earth’s Long-term Climate Changes  Cooling and warming periods – affect evolution and extinction of species  Five mass extinctions Eliminated half of the earth’s species Many theories why this occurred  Opportunities for the evolution of new species

Northern Hemisphere over 18,000 Years

Fig. 4-4, p ,000 years before present Modern day (August) Northern Hemisphere Ice coverage

4-3 What Is an Ecological Niche?  Concept 4-3 As a result of biological evolution, each species plays a specific ecological role called its niche.

Unique Roles for Species  Generalist species  Specialist species  Specialists prone to extinction – giant panda

Specialized Feeding Niches in Birds

Fig. 4-5, p. 68 Louisiana heron wades into water to seize small fish Black skimmer seizes small fish at water surface Ruddy turnstone searches under shells and pebbles for small invertebrates Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds 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 Herring gull is a tireless scavenger Flamingo feeds on minute organisms in mud Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation Piping plover feeds on insects and tiny crustaceans on sandy beaches Knot (sandpiper) picks up worms and small crustaceans left by receding tide Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak

Science Focus: Cockroaches  Existed for 350 million years – 3,500 known species  Highly adapted, rapidly producing generalists Consume almost anything Endure food shortage Survive everywhere except polar regions Avoid predation  Carry human diseases

4-4 How Do Extinction, Speciation, and Human Activities Affect Biodiversity?  Concept 4-4A As environmental conditions change, the balance between formation of new species and extinction of existing ones determines the earth’s biodiversity.  Concept 4-4B Human activities decrease the earth’s biodiversity by causing the premature extinction of species and by destroying or degrading habitats needed for the development of new species.

Speciation  Geographic isolation  Reproductive isolation  Millions of years in slow-producing species  Hundreds of years in rapidly reproducing species

Geographic Isolation

Fig. 4-6, p. 70 Spreads northward and southward and separates Arctic Fox Gray Fox Different environmental conditions lead to different selective pressures and evolution into two different species. Adapted to cold through heavier fur, short ears, short legs, and short nose. White fur matches snow for camouflage. Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Northern population Southern population Early fox population

Extinction  Endemic species vulnerable to extinction  Background extinction  Mass extinction  Balance between speciation and extinction determines biodiversity of earth  Speciation generally more rapid than extinction

Extinction through Habitat Loss Fig. 4-7, p. 70

Human Activities and Extinction  Cause premature extinction of species  Earth took millions of years to recover from previous mass extinctions

4-5 How Might Genetic Engineering Affect the Earth’s Life?  Concept 4-5 Genetic engineering enables scientists to transfer genetic traits between different species – a process that holds great promise and raises difficult issues.

Humans Change Population Genetics  Artificial selection – slow process  Selective breeding  Crossbreeding – not a form of speciation  Genetic engineering

Results of Genetic Engineering  Genetically modified organisms (GMOs)  Gene splitting rapid vs. artificial selection  Modified crops, new drugs, fast-growing animals

Steps in Genetic Engineering (1)

Steps in Genetic Engineering (2)

Fig. 4-8, p. 72

Fig. 4-8a, p. 72 Phase 1 Gene Transfer Preparations Host cell Enzymes integrate plasmid into host cell DNA. A. tumefaciens (agrobacterium) Agrobacterium takes up plasmid Foreign gene integrated into plasmid DNA, which can be used as a vector plasmid Extract plasmid A. tumefaciens Plant cell Foreign gene if interest Extract DNA Phase 2 Make Transgenic Cell

Fig. 4-8b, p. 72 Phase 3 Grow Genetically Engineered Plant Foreign DNA Host DNA Nucleus Transgenic plant cell Cell division of transgenic cells Cultured cells divide and grow into plantlets (otherwise teleological) Transgenic plants with desired trait

Pros and Cons of Genetic Engineering  Pros May help cure genetic defects May improve organisms May lead to development of secondary evolution  Cons Ethical issues Privacy issues Designer babies GMO crossbreeding with original organisms

Genetically Engineered Mice Fig. 4-9, p. 73

Animation: Carbon Bonds

Animation: Stanley Miller’s Experiment

Animation: Evolutionary Tree of Life

Animation: Stabilizing Selection

Animation: Disruptive Selection

Animation: Moth Populations

Animation: Adaptive Trait

Animation: Speciation on an Archipelago

Animation: Evolutionary Tree Diagrams

Animation: Gause’s Competition Experiment

Animation: Species Diversity By Latitude

Animation: Humans Affect Biodiversity

Animation: Habitat Loss and Fragmentation

Animation: Transferring Genes into Plants

Video: Ancient Human Skull PLAY VIDEO

Video: Asteroid Menace PLAY VIDEO

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Video: Cloned Pooch PLAY VIDEO

Video: Creation vs. Evolution PLAY VIDEO

Video: Dinosaur Discovery PLAY VIDEO

Video: Glow-in-the-Dark Pigs PLAY VIDEO

Video: Hsing Hsing Dies PLAY VIDEO

Video: Mule Clones PLAY VIDEO

Video: New Species Found PLAY VIDEO

Video: Penguin Rescue PLAY VIDEO