Evolution and Biodiversity Chapter 4

Key Concepts Origins of life Origins of life Evolution and evolutionary processes Evolution and evolutionary processes Ecological niches Ecological niches Species formation Species formation Species extinction Species extinction

How Did We Become Such a Powerful Species So Quickly? Adaptive traits Adaptive traits Human weaknesses Human weaknesses Opposable thumbs Opposable thumbs Walk upright Walk upright Intelligence Intelligence Environmental impacts Environmental impacts p. 67

Origins of Life Chemical evolution Chemical evolution Biological evolution Biological evolution

How Do We Know Which Organisms Lived in the Past? Fossil record Fossil record Radiometric dating Radiometric dating Ice cores Ice cores DNA studies DNA studies Fig. 4-2, p. 65

Fig. 4-3, p. 66 Modern humans (Homo sapiens) appear about 2 seconds before midnight Recorded human history begins 1/4 second before midnight Origin of life (3.6–3.8 billion years ago) Biological Evolution of Life

Biological Evolution Evolution Evolution Theory of evolution Theory of evolution Microevolution Microevolution Macroevolution Macroevolution

Microevolution Gene pool Gene pool Genetic variability Genetic variability Mutations Mutations Mutagens Mutagens Natural selection Natural selection

Fig. 2-5 p. 33 A human body contains trillions of cells, each with an identical set of genes. There is a nucleus inside each human cell (except red blood cells). Each cell nucleus has an identical set of chromosomes, which are found in pairs. A specific pair of chromosomes contains one chromosome from each parent. Each chromosome contains a long DNA molecule in the form of a coiled double helix. Genes are segments of DNA on chromosomes that contain instructions to make proteins—the building blocks of life. The genes in each cell are coded by sequences of nucleotides in their DNA molecules. Genetic Materials

Natural Selection Differential reproduction Differential reproduction Adaptation (adaptive trait) Adaptation (adaptive trait) Coevolution Coevolution

Ecological Niches and Adaptation Ecological niche Ecological niche Habitats Habitats Fundamental niche Fundamental niche Realized niche Realized niche

Specialized Feeding Niches for Birds Black skimmer seizes small fish at water surface Flamingo feeds on minute organisms in mud Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation 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 Louisiana heron wades into water to seize small fish Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Knot (a sandpiper) picks up worms and small crustaceans left by receding tide Herring gull is a tireless scavenger Ruddy turnstone searches under shells and pebbles for small invertebrates Piping plover feeds on insects and tiny crustaceans on sandy beaches Fig. 4-10, p. 72

Broad and Narrow Niches and Limits of Adaptation Generalist species Generalist species Specialist species Specialist species Limits of adaptation Limits of adaptation

Fig. 4-4, p. 68 Niche separation Specialist species with a narrow niche Generalist species with a broad niche Niche breadth Region of niche overlap Niches of Specialist and Generalist Species Resource use Number of individuals

Cockroaches: Nature’s Ultimate Survivors Fig. 4-A, p. 69

Fig. 4-6, p. 70 Unknown finch ancestor Fruit and seed eaters Insect and nectar eaters Greater Koa-finch Kona Grosbeak Akiapolaau Maui Parrotbill Kuai Akialaoa Crested Honeycreeper Apapane Amakihi Evolutionary Divergence of Honeycreepers

Misconceptions of Evolution “Survival of the fittest” “Survival of the fittest” “Progress to perfection” “Progress to perfection”

Speciation What is speciation? What is speciation? Geographic isolation Geographic isolation Reproduction isolation Reproduction isolation

Fig. 4-9, p. 70 Spreads northward and southward and separates Arctic Fox Gray Fox Adapted to cold through heavier fur, short ears, short legs, 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. Different environmental conditions lead to different selective pressures and evolution into two different species. Northern population Southern population Early fox population Geographic Isolation can Lead to Speciation

Factors Leading to Extinction Plate tectonics Plate tectonics Climatic changes over time Climatic changes over time Natural catastrophes Natural catastrophes Human impacts Human impacts

Extinctions Background extinctions Background extinctions Mass extinctions Mass extinctions Mass depletions Mass depletions Human impacts Human impacts

PANGAEA GONDWANALAND LAURASIA NORTH AMERICA ANTARTICA AUSTRALIA AFRICA EURASIA SOUTH AMERICA INDIA MADA GASCAR 225 million years ago135 million years ago 65 million years agoPresent Fig. 4-8, 4-9 p. 69 “Continental Drift” (Plate Tectonics): The Breakup of Pangaea

Mass Extinctions of the Earth’s Past Fig. 4-9, p. 73

Fig. 4-10, p. 74 Terrestrial organisms Marine organisms Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian Pre-cambrain Number of families Millions of years ago Changes in Biodiversity over Geologic Time

Future of Evolution Artificial selection Artificial selection Genetic engineering (gene splicing) Genetic engineering (gene splicing) Genetic modified organisms (GMOs) Genetic modified organisms (GMOs) Cloning Cloning Ethical concerns Ethical concerns

Fig. 4-11, p. 75 Phase 1 Make Modified Gene Identify and extract gene with desired trait Identify and remove portion of DNA with desired trait Remove plasmid from DNA of E. coli Insert extracted DNA (step 2) into plasmid (step3) Insert modified plasmid into E. coli Grow in tissue culture to make copies Cell plasmid E. coli DNA Genetically modified plasmid Extract plasmid Genetic Engineering Gene of interest Extract DNA

Fig. 4-11, p. 75 Phase 2 Make Transgenic Cell Transfer plasmid copies to a carrier agrobacterium Agrobacterium inserts foreign DNA into plant cell to yield transgenic cell Transfer plasmid to surface microscopic metal particle Use gene gun to inject DNA into plant cell A. tumefaciens (agrobacterium) Host DNA Foreign DNA Genetic Engineering E. coli Nucleus

Fig. 4-11, p. 75 Phase 3 Grow Genetically Engineered Plant Transgenic cell from Phase 2 Cell division of transgenic cells Culture cells to form plantlets Transgenic plants with new traits Transfer to soil Genetic Engineering

p. 71 Genetically Engineered Mouse