evolution and biodiversity chapter 4. concept 4-3 as a result of biological evolution, each species...
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Evolution and Biodiversity
Chapter 4
Concept 4-3 As a result of biological evolution, each species plays a specific ecological role called its niche.
Niche – sometimes thought of as the job or vocation of a species; involves all of its environment
Habitat – the place where an organism lives; where you would go to find this organism
Unique Roles for Species• Generalist species • Specialist species
• Specialists prone to extinction – giant panda
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
Panda and its Food
Fig. 4-4, p. 68
Nicheseparation
Specialist specieswith a narrow niche
Generalist specieswith a broad niche
Nichebreadth
Region ofniche overlap
Niches of Specialist and Generalist Species
Resource use
Nu
mb
er o
f in
div
idu
als
Specialized Feeding Niches in Birds
Fig. 4-5, p. 68
Louisiana heronwades into waterto seize small fish
Black skimmerseizes small fishat water surface
Ruddy turnstone searches
under shells and pebbles
for small invertebratesAvocet 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 probesdeeply into mud insearch of snails,marine worms, andsmall crustaceans
Herring gullis a tirelessscavenger
Flamingo feeds onminute organismsin mud
Scaup and other divingducks feed on mollusks,crustaceans, and aquaticvegetation
Piping plover feeds on insects and tiny crustaceans on sandy beachesKnot (sandpiper)
picks up wormsand small crustaceansleft by receding tide
Oystercatcher feeds onclams, mussels, and othershellfish into which itpries 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
Cockroaches: Nature’s Ultimate Survivors
Fig. 4-A, p. 69
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
Present225 million years ago65 million years ago135 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. 67
18,000years beforepresent
Modern day(August)
Northern HemisphereIce 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
Panda and its Food
Panda and its Food
Fig. 4-4, p. 68
Nicheseparation
Specialist specieswith a narrow niche
Generalist specieswith a broad niche
Nichebreadth
Region ofniche overlap
Niches of Specialist and Generalist Species
Resource use
Nu
mb
er o
f in
div
idu
als
Specialized Feeding Niches in Birds
Fig. 4-5, p. 68
Louisiana heronwades into waterto seize small fish
Black skimmerseizes small fishat water surface
Ruddy turnstone searches
under shells and pebbles
for small invertebratesAvocet 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 probesdeeply into mud insearch of snails,marine worms, andsmall crustaceans
Herring gullis a tirelessscavenger
Flamingo feeds onminute organismsin mud
Scaup and other divingducks feed on mollusks,crustaceans, and aquaticvegetation
Piping plover feeds on insects and tiny crustaceans on sandy beachesKnot (sandpiper)
picks up wormsand small crustaceansleft by receding tide
Oystercatcher feeds onclams, mussels, and othershellfish into which itpries 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
Cockroaches: Nature’s Ultimate Survivors
Fig. 4-A, p. 69
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 northwardand southwardand separates
Arctic Fox
Gray Fox
Different environmentalconditions lead to differentselective pressures and evolutioninto two different species.
Adapted to coldthrough heavier fur, short ears, short legs, and short nose. White fur matches snow for camouflage.
Adapted to heat through lightweightfur and long ears, legs, and nose, whichgive off more heat.
Northernpopulation
Southernpopulation
Early foxpopulation
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 1Gene Transfer Preparations
Host cell
Enzymes integrate plasmidinto host cell DNA.
A. tumefaciens(agrobacterium)
Agrobacterium takes up plasmid
Foreign gene integrated intoplasmid DNA, which can beused as a vector
plasmid
Extractplasmid
A. tumefaciens
Plant cell
Foreign geneif interest
Extract DNA
Phase 2Make Transgenic Cell
Fig. 4-8b, p. 72
Phase 3Grow GeneticallyEngineered Plant
Foreign DNAHost DNA
Nucleus Transgenicplant cell
Cell division oftransgenic cells
Cultured cellsdivide and growinto plantlets(otherwiseteleological)
Transgenic plantswith 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
PLAYVIDEO
Video: Asteroid Menace
PLAYVIDEO
Video: Bachelor Pad at the Zoo
PLAYVIDEO
Video: Cloned Pooch
PLAYVIDEO
Video: Creation vs. Evolution
PLAYVIDEO
Video: Dinosaur Discovery
PLAYVIDEO
Video: Glow-in-the-Dark Pigs
PLAYVIDEO
Video: Hsing Hsing Dies
PLAYVIDEO
Video: Mule Clones
PLAYVIDEO
Video: New Species Found
PLAYVIDEO
Video: Penguin Rescue
PLAYVIDEO