The final exam will be in Weeks Hall AB20 (our normal lecture room), except two sections will take the exam upstairs. Monday May 12, 12:25 pm

The final exam will be cumulative for lecture material, but the last third of the course will be emphasized. Only the readings since the second midterm will be covered.

Be sure to study the review sheets for the first and second exams. The review sheets are meant as a study guide; they are NOT an exhaustive list of everything you need to know. Here are the topics we have covered since the second midterm:

Ordovician radiation of marine life

life moves onto land
problems for animals and plants in leaving the water
earliest spores likely to be from land plants: Ordovician
adaptations of land plants: cuticle, stomata, xylem
early non-vascular plants, vascular plants, evolution of trees
early terrestrial arthropods in the Silurian

vertebrate evolution
jawless fish in the Cambrian; jawed fish in the Late Silurian
transition from lobe-finned fish to amphibians
characteristics of lobe-finned fishes
impetus out of the water
Ichthyostega as a transitional fossil (know both its amphibian and fish-like characteristics)

preadaptation (example using fish-amphibian transition)

amphibian evolution: Carboniferous heyday, scanty fossil record after that
modern amphibians
typical and atypical reproductive strategies
declining populations; multiple causes
amphibians are sensitive environmental indicators
permeable skin
insect-rich (= pesticide-rich) diet

reptiles
general characteristics of a reptile (amniote egg; direct development)
other characteristics of reptiles today (ectothermic; scaly skin)

study the reptile family tree
basic groups - distinguished by number of holes in side of skull:
1) anapsid; no holes (primitive state); includes turtles and stem reptiles
2) diapsid; two holes; includes most living reptiles and most Mesozoic reptiles
3) synapsid; one hole; includes many Permian reptiles and ancestors to mammals

overview of reptile history:
transition from amphibians to reptiles not well documented
earliest reptiles in Pennsylvanian; successful in Permian; wildly successful in Mesozoic; successful in Cenozoic in warm climates
reptile groups:

1. turtles (Triassic origin; highly modified body plan)

2. tuataras (only two species; "living fossils"; survive on islands near New Zealand)

3. lizards (diverse today; largest living lizard = Komodo dragon, how did it get so big?; mosasaurs were successful Mesozoic marine lizards)

4. snakes
Cretaceous snakes with legs
very successful group today; live in almost all habitats
"key innovation" = modifications of skull and jaw (incl. skull bones separate; left and right sides of jaw move independently)
most advanced fangs are anterior, hollow, and collapsible
huge number of vertebrae give strength and flexibility to body

5. ichthyosaurs (Triassic to Cretaceous)
extremely specialized for aquatic life, so much so that uncertain where on reptile tree they belong
bore live young
excellent example of convergence; body features similar to dolphins or sharks but evolved them independently (what are homologous and analogous features?)

6. crocodiles
earliest in Triassic; small, bipedal, terrestrial
became aquatic and huge (50 ft.) in Jurassic to Cretaceous time

7. pterosaurs (Triassic to Cretaceous)
earliest flying vertebrates; include largest flying animals ever
wing supported on single elongated 4th finger

8. dinosaurs - two main divisions (based on hip structure)
1. ornithischians (bird hips) include:
a) ceratopsians: stocky, quadrupedal, known for large skulls wth frills and horns
b) pachycephalosaurs: bipedal, some with immensely thick domed skulls probably used in head-butting contests (like bighorn sheep)
c) ornithopods
i. Iguanodon: first dinosaur discovered; peculiar hand with spiked thumb, opposable pinky, hooves on remaining three digits
ii. hadrosaurs: "duckbills"; highly social, relatively common, evidence for parental care of nests; very rapid growth rates
d) stegosaurs: known for series of plates on back (probably for thermoregulation) and for tiny brain
e) ankylosaurs: known for whole body covering of bony armour and massive spiked tail club
2. saurischians (lizard hips) include:
a) sauropods: "Brontosaur" type dinosaurs; include largest land animal, and longest animal ever (largest whales weigh more)
b) theropods: includes all carnivorous dinosaurs; ancestral to birds

vertebrate temperature regulation
basic terms (endotherm vs. ectotherm; homeotherm vs. poikilotherm)
evidence for endothermy in dinosaurs includes:
1. erect posture: requires high metabolism to maintain, allows for more efficient breathing and running, today seen only in endotherms
2. paleogeographic distribution: some dinosaurs were found in regions too cold for ectotherms
3. many dinosaurs must have had relatively high blood pressure
4. very large dinosaurs were "inertial homeotherms"

evolution of birds
birds probably arose from small bipedal dinosaurs
Archaeopteryx: early bird from the Jurassic of Germany
Solnhofen Limestone has soft part preservation, incl feathers
good transitional form
reptilian features: teeth, claws on wings, long bony tail, nonfused ribs and pelvic bones
avian features: fused clavicles, feathers (and wings)
two hypotheses for origin of bird flight: "ground up" or "tree down"

synapsid history
early branch off stem reptile line
most important reptile group in Permian-early Triassic
gave rise to mammals in the late Triassic

mammals
general characteristics: bear live young; milk-giving; endothermic; high metabolism; hair
these largely physiological features have anatomical correlates so we can trace their evolution from synapsids

trends in the evolution of mammals from synapsids:
1. skeletal (leg position)
2. teeth, jaw, and ear (incl: tooth form, tooth replacement, jaw muscles, jaw articulation and middle ear bones - what are the differences between reptiles and mammals? how do all these changes link together?)

mammal history
first appear in Triassic
small and nocturnal till end of Cretaceous (2/3 of their history)
major radiation during Paleocene to Eocene (right after Cretaceous mass extinction)

groups of mammals (distinguished by reproductive features)
1. monotremes
Jurassic split from the rest of mammals
females lay eggs!
have some characteristics of both mammals and reptiles, plus unique characteristics
2. marsupials
females give birth to extremely underdeveloped baby; remainder of development in pouch
early Cretaceous divergence from placentals
evolution parallels the adaptive radiation of placentals (multiple examples of convergence)
3. placental mammals
females retain baby within body until relatively advanced stage of development
most diverse group of modern mammals

interesting placental groups include:

bats: ~1/4 of all mammal species
earliest in Eocene - very modern appearance, echolocating (how do we know?)
2 major groups: fruit bats (large, visual) and microbats (echolocation)
ecological importance - what roles do they play?

mammals evolved marine forms at least 3 times:

1. sirenians: evolved in Eocene; common ancestor with elephants
2. pinniped Carnivores: evolved in Miocene from bear/walrus/dog-like ancestor
3. cetaceans
earliest in Eocene; carnivorous ungulate ancestor
Oligocene split in the whale lineage (toothed whales and baleen whales) coincides with origin of circumpolar current

primates
characterized by vocal communication, visual orientation, manual dexterity
retain some "primitive" features: unspecialized skeleton, 5 fingers and toes, generalized dentition

study the primate family tree:
prosimians (small, tree-dwellers, incl lorises, tarsiers, lemurs)
Madagascar: history of the island, extinctions (incl lemurs, elephant birds)
monkeys ­ old world and new world
Asian apes­ gibbons and orangs
African apes ­ gorillas and chimps
noted restriction of geographic ranges of apes
divergence times between human lineage and apes

human evolution
variety of primitive apes in Miocene and Pliocene
"australopiths"
evolved from one of primitive apes in the Pliocene
range: 4.4 to 1 Ma; at least 3 genera
small brained, small size, bipedal
southern and eastern Africa
gracile and robust forms

Homo- first appearance at 2.5 Ma (coexisted with australopiths)
several species
left Africa by 1.8 Ma
incl. neanderthals

trends in human evolution
1. body size increase
2. relative brain size increase

events at 2.5 Ma - connection between environmental and evolutionary change
1. climate change (global cooling; African drying [forests->savannas])
2. African ungulates change from browsers to grazers
3. human ancestors in Africa (turnover of australopiths; evolution of robust forms; earliest Homo)

extinction
background extinction versus mass extinction (how defined?)
see plots of family level extinction rates and family diversity

Late Permian mass extinction
severity: 52% families, ~80% species
who died?
possible causes? (climate change, sea level drop, continents clustered, extensive volcanism, oceanic overturn, methane hydrate release)

Late Cretaceous mass extinction
severity: 11% families, estimated 75% species extinct
who died?
possible causes? (meteorite impact; volcanism; what are unanswered questions?)

Late Pleistocene
ice cover and sea level
Late Pleistocene extinctions - overkill versus climate change
perspective: several pulses of extinction in the last 10 m.y.
(horse evolution in North America)
patterns of Late Pleistocene extinctions:
1. large mammals decimated
2. different intensities on different continents
3. different timing on different continents
4. fate of small mammals on islands versus continents
5. extinction without replacement

extinctions today
tropical rain forests: extent, number of species
rates of destruction of tropical rain forests
rates of extinction - how do they compare with fossil record?

what is biological wealth?
raw materials; medicines; food; genetic resources

what do intact ecosystems do?
a. pollination, pest control, seed dispersal...
b. waste treatment
c. prevention of flooding, soil erosion, drought
d. local and global climate control

global climate
what is the greenhouse effect?
CO2 and CH4: history, sources (incl. methane hydrates)
Greenland ice cores provide detailed climate record (wild swings are common; humans proliferated in unusually calm interval)
feedbacks; instability

critical issues in human overpopulation:
a. poverty
b. demographics
c. sustainability
d. consumerism ...make your footprint small