Ch. 14: How Biological Diversity Evolves:  both Ch 13 & 14, same, short summary,

This chapter covers two topics: 1) the formation of new species & 2) macroevolution
Macroevolution is also part of later chapters on protists, fungi, plants & animals

A. Biology & Society:
0E: Current Mass Extinction: species go extinct without even being described (more in ch 20)
1E: Asteroids: 1/2/a few > K/T extinction (dinosaurs), Shiva, AZ,  BUT, burst of volcanic activity?
      After K/T, mammals replaced reptiles. all mass extinctions (later in Ch)  same
2E: 1or 2 troublesome species?: West Nile virus: USA cases, CDC: 2007, control of culex
Culex pipiens main carrier, other species involved, < click culex
In Europe: two species of C. pipiens? - have different ecological niches (described in box)

B. Macroevolution & Diversity of Life (intro., more below) paleontology = fossils
    Macroevolution: is more than microevolution = adaptation but not speciation:
              = change over time, & branching: biodiversity increased, source
              = origin of novelty: feathers came from scales, wings from limbs,
    How to study macroevolution:
    Fig 2: Speciation is by branching, but a species accumulates change over time too
    Evolution is non-branching & branching:     summary.

    Checkpoint p 271:
    1. define microevolution & macroevolution
    2. Can non-branching evolution increase the number of species?
    3. Speciation fig 2 is branching only?
C. Origin of Species Darwin site
  1. A species: must produce fertile offspring, & definition's limitations applied to all organisms, fig 6
  2. above link: for prokaryotes (mostly asexual reproduction): 98.7% similar DNA
    3. sterile hybrids: liger, tigon, best: all hybrids, scroll,
    Fig 4 Reproductive Barriers: pre- & post- zygotic (zygote = fertilized egg):
  3. PRE- five isolations: temporal, habitat/spatial, behavioral fig 5, mechanical, gametic
  4. POST- three isolations: inviability, (hybrid) sterility (above), breakdown/unfit

  6. Speciation fig 7 has two mechanisms,
  7. Allopatric: usual way = apart: fig 8, & 9, note!
    8. Sympatric: together, occurs if both AA & aa are fitter than Aa!, but one gene, not a population?
    hybrid corn is MORE vigorous, & sterile so farmers must buy seed every year     
    OR by massive mutation: polyploidy/primrose fig 10,  hollyhock, wheat fig 11,  similar
    wiki adds     peripatric: related to Founder effect, small isolated population with distinctly different genome
              & parapatric: reads like nitpicking version of allopatric

    Tempo of Speciation (there is evidence for both)
Phyletic gradualism: fig 14, pace is steady, human, which is it?
Punctuated equilibrium: the pace of evolution varies: mutation in homeotic gene
original insect had four wings?, so mutations produced Diptera (flies) with two wings & two halteres
Relate a "sudden" geological appearance to our "human" sense of time.

    CHECKPOINT p 279
    1. Define a species
       What is the problem with the definition when applied to prokaryotes?
    2. Why is allopatric speciation less likely on an island close to the mainland than on one further away?
    3. The steps in wheat evolution are examples of ? speciation
    4. Is evolution gradual or punctuated equilibrium: why are the missing links rare?
D. Evolution of Biological Novelty  
  1. Adaptation of old structures for new functions:
  2. Exaptation:  modifying a machine as it is running, includes hand & dogs licking humans
    3. reptile with hollow bones, feathers for warmth & wing-like fore-limbs = pre-bird > fig 13
  3. Paedomorphosis fig 14 creates new species by retaining juvenile features:
    4. is mostly neoteny: toy dogs, flightless birds, humans fig 15, & domestication, silver fox
CHECKPOINT
1. Exaptation is preferred term to pre-adaptation, why?
2. How was the evolution of axoloti like human evolution? salamander
3. Describe a possible missing link between reptiles & mammals,  one step,
4. If anyone suggests that you are just a big baby, how should you respond?
5. Why is the vertebrate skeleton, a good choice for deciding if adaptations
     are homologous or analogous? two reasons:  1,  2 scroll for examples, source

HALF-WAY

E) Earth History & Macroevolution:  resource: macroevolution & diversity

     1. Geologic Time & the Fossil Record: fossil record: list of fossils, "missing links"
     Sedimentary rocks are richest source of fossils, fig 16: click on rock cycle to see why
     Fossil's age is rock's: insect/amber, DNA in amber, footprints, mammoth, petrified forest

     Geologic time scale: like table 1 < review, it is enough, detailed, detailed, wiki: detailed
       Four eras (below) Precambrian, Paleozoic, Mesozoic, & Cenozoic
       Each era ends with a mass extinction & is followed by explosion in diversity: e.g.
       Cambrian explosion is best known from Burgess shale, video animation, location, Farabee,
    Use radiometric dating, fig 17, to fix age of rocks: wiki:
    1) many elements exist as ratios of isotopes e.g. carbon, list of radioactive isotopes
    2) different isotopes emit different radiation: alpha, gamma, radon
    3) begining when rock is formed the isotopes caught in it break down, fig 17
    4) amount of break-down gives age of rock
  1. video

    2. 2. Plate Tectonics & Macroevolution: units Mya = millions of years ago
  1. as life was evolving the continents were moving around: fig 18, Resource
  2. Much evolution of life came before Pangea, supercontinent formed ~250 Mya, fig 19
    3. The Silurian: 420 Mya: a coral reef existed where Chicago is now: Thornton quarry
    Three mass extinctions occured either before of during the formation of Pangea
    Early mass extinctions were due to continental drift: land moved towards or away from the equator
     - this raised or lowered sea levels a lot, & changed the climate on land
      ~250 Mya: Pangea, ~180 Mya > slowly separated, later recombined differently:
  3. e.g. Mesozoic fossils in Africa & S. America match: scroll past table to fossils;
  4. & Australia's "pre-mammal" separation.
  5. 250 My in the future a new single continent will form
          3. Mass Extinctions & Explosive Diversifications of Life: < fig. includes two of the five
  1. mass extinctions: causes:  flood basalt, some suggestions below.
    2. mass extinctions,  are not as clear cut as the name suggests
    & are followed by times of opportunity, last sentence, but not the present mass extintion!
Global climate change resource: present & past events,  evolution & history of life,

KNOW THIS SUMMARY   Field museum
Pre-Cambrian: 4500-540 Mya (88%), earth forms, life begins, photosynthesis, eukaryotes, animals, images 
Paleozoic: 540-245 (6.5%), land colonized: early plants, then seeds, fish, amphibians, reptiles, images
ends with 3rd mass extinction
Mesozoic: 245-65 (4%), pangea breaks up + Laurasia, dinosaurs & gymnosperms dominate,
flowering plants & mammals begin, images, ends with 5th mass extinction
Cenozoic: 65 Mya to present (1.4%), modern continents form, rise of mammals & flowering plants, images
The recent Ice Ages are due to periodic changes in Earth's orbit from circular to elipse

Activity p 286: did meteor kill dinosaurs?
1E: Asteroids: 1/2/a few > K/T extinction (dinosaurs), Shiva, AZ,  BUT, burst of volcanic activity?
      After K/T, mammals replaced reptiles. all mass extinctions (later in Ch)  same

Checkpoint p 286
1. How long did prokaryotes live before eukaryotes appeared?
2. A skull has C14:C12 ratio 1/16 (6.25%) of present (living).  use fig 17: how old is it?,  wiki,
3. How many continents at time of Pangea?  Paleozoic?  Mesozoic?  Cenozoic?

F. Classifying the Diversity of Life

         1. Some Basics of Taxonomy = classification;
            systematics = taxonomy & fossil record: cladogram
  1. Carolus Linneaus invented binomial system of species names, & hierarchical system of classification
  2. The binomial system fig 21 (click it) identies by genus & species names.
  3. List the levels of taxonomic groups: (each level is homology, more below)
  4. domestic cat: fig 21, fig 21
  5. genus & species = Felis catus,
  6. family, Felidae, 
  7. order, Carnivora,      
  8. class, Mammalia,         
  9. phylum, Chordata, more than vertebrates = subphylum, chordates are named for notochord
  10. kingdom, Animalia, (multicellular not unicellular = protista)
  11. domain, Eukarya
       2. Classification & Phlogeny
    Sorting homology from analogy
    Homologies are used to create classifications, (in lab ex., fig 22 carnivora),
    homologies come from common ancestor: fig 22 & 24 (below), analogies from convergent evolution
  1. Convergent evolution (wings or fins) makes interpreting homologies difficult.
  2. Fossil record helps 
  3. Panda thumb is homologous to wrist bone (human wrist scroll), analogous to thumb digit I.

  5. Classification Systems: first: two kingdoms < see summary table
    6. most often seen in biol 206: five/six kingdoms
  6. most recent, fig 26: three domains < molecular differences scroll < archaea first >
  7.  
    8. oldest DNA used to reconstruct ecosystems, conflicts with fig 23: DNA 40 Mya: seems true
  8. Classification systems are revised as new information becomes available, eg DNA in lab ex
  9. Cladistics is the new Systematics: 
  10. identify branch points: superior to counting skeletal similarities in lab ex
    11. like fig 24: vertebrae > hair & mammary glands > gestation > long gestation
CHECKPOINT p 291
1. How much classification do we share with cat?
2. Our forearm and bat wing have same bones thus they are ......?
    The wings of the bat and bee are not .....?, they are .....?
3. Name the study of the relationships between living organisms
   Name the study of relationships btw organisms & their ancestors
    Name given to a species and all its ancestors
4. How many domains are there? Which is ours?
5. Why is it misleading to label Darwin's ideas as just a theory?  Gravity?  Universe?  Relativity?