Biology Study Guide
Evolution Chapters 14 – 16
Test Friday April ____
Chapter 14
Oldest rocks date the earth’s age at around 4.5 billion years. Could be older.
Abiogenesis – belief in spontaneous generation of some life forms from nonliving matter
Biogenesis – life comes only from preexisting life
Intelligent Design, or Creationism, disagrees with evolution of life forms.
Scientists who helped prove biogenesis (by disproving abiogenesis):
Redi: maggots on meat
Spallanzani: microbes in broth
Pasteur: swan-necked flasks. Life does not arise from food and air alone
Oparin: hypothesized that life was synthesized on the early earth. First, inorganic chemicals formed
organics, then protocells.
Chemical origins of life were first tested by Miller and Urey. They made amino acids, etc. this way.
Gases in early atmosphere were very different from the gases in our air today. Not much oxygen.
Coacervates: collection of droplets composed of molecules of different types of organic compounds
First cells were prokaryotic, anaerobic, and probably heterotrophic
Microfossils of earliest cells found in 3.5 byo rock
“Endosymbiosis”: 1st eukaryotic cells may have formed by large bacteria engulfing smaller aerobic or
photosynthetic prokaryotes (became first organelles).
Chapter 15
Evolution: life forms have changed over a long period of time.
Fossils show us preexisting forms of life: remains, molds, casts, imprints.
Radiometric dating; isotopes; half-life
Jean LaMarck – early evolutionary theory; “acquired characteristics”, based on use or disuse
Charles Darwin – traveled on the Beagle for 5 years; collected and observed
“On the Origin of Species” – famous book detailing how evolution works by natural selection
Alfred Russel Wallace – came up with idea of natural selection independent of Darwin
Those with most favorable variations in phenotype are most likely to survive and reproduce; “survival of
the fittest”.
Good genes most likely to be passed to successive generations
Common ancestry – modern species are related to each other; evolutionary pattern in which different
species evolve from one ancestral group.
Convergent evolution – similar look but totally different species (dolphins, sharks)
Divergent evolution – 2 or more related populations become more dissimilar because of separation and
different environmental pressures. Ex: Galapagos finches
Parallel evolution (coevolution) – evolutionary changes occur because of need to survive in close
proximity to another organism (flowers, pollinating animals)
Homologous structures – features that are different in use, but the same in structure (evidence of
common ancestry)
Analogous structures – features that are used the same, but have a different structure (do not show a
common ancestry)
Vestigial structures – useful to ancestor but not to modern version (appendix, coccyx bone)
Biochemical similarities of DNA or protein sequences can be compared/contrasted
Chapter 16
Speciation – evolutionary formation of a new biological species; usually a division of a single population
into 2 or more genetically distinct groups.
“Allopatric speciation” – geographic barriers prevent gene flow
Reproductive isolation can also cause speciation - Prezygotic and post zygotic barriers to mating.
Species – a group of like organisms that are capable of producing offspring.
Population – all members of the same species in one place, time.
Gene pool – collection of genes for all traits in a population
Gene flow – movement of alleles into or out of a population due to migration
Extinction
Hardy-Weinberg Principle – genetics (allele frequencies) in a population will remain in equilibrium under
certain conditions. What are these conditions?
Microevolution: changes in a population over time, due to:
Directional selection
Stabilizing selection
Disruptive selection
Sexual selection
Macroevolution: speciation events that take place over the course of a long time.
Gradualism –vs- punctuated equilibrium theory of speciation.