CLUSTER 70B Study Guide - Final Guide: Diagenesis, Taphonomy, Adaptive Radiation
Final Study Guide
Lecture 1
• Evolution: change through time
o Microevolution: change in gene frequencies in a population
o Macroevolution: descent with modification
• Natural Selection: mechanism for evolution
o Individuals vary, more produced than can survive, variation influences survival
and reproduction of individuals
o If variation is heritable = Evolution!
• Evolution is random and selective, works on populations, and is genetic at the basic level
• Adaptations: characters selected for in a particular environment
• Ecology: interactions of organisms with each other and the environment
o Evolution is a reaction to ecology and gives depth of time
• Lines of evidence:
o Direct Observation: reduced in size, functioned in ancestors (vestigial structures:
no apparent function, appendix)
o Comparative Anatomy: study of similarities and differences in morphology
(animal and plant form)
▪ Homology: derived from common ancestor
▪ Analogy: similar in form but not from ancestor (convergence)
o Classification/Taxonomy: organisms can be arranged into groups based on shared
characteristics
o Comparative Genomics: closely related organisms share more genes
o Fossil Record: extinct organisms can be classified in groups of existing
organisms, descent with modification, transitional forms, will always be
incomplete
o Biogeography: study of the geographical distributions of animal and plant life
(adaptive radiation)
o Embryology/ Development: development of homologous structures in embryo
follow sequence, structures appear and disappear (tails, gills)
▪ Ontogeny: development and growth of individual zygote to adult
• Oxygen isotope ratios show if aquatic animals lived in freshwater or saltwater
Lecture 2
• Fossils: evidence of past life (body/chemical/trace)
• Diagenesis: physical/ chemical process that leads to fossilization
• Types of Fossils:
o Whole Body: mummification, frozen
o Preservation of hard parts and petrification
o Molds and casts
o Trace fossils (ichnofossils)
o Chemical traces
• Taphonomy: study of processes by which animals fossilize,
o consumption & decomposition -> exposure & weathering -> transport & burial
-> fossilization & exhumation
• Lagerstatte: fossil locations with exceptional preservation
• Index (Guide) Fossils: easily distinguishable, widespread, short periods of geologic
time, abundant
• Time Periods: Precambrian (all)
o Paleozoic (544-251), P/T Extinction, Mesozoic (251-65), K/T Extinction,
Cenozoic (65-present)
• Evolution of Evolution:
o Empedocles: only the more fit survive
o Essentialism: general thought, fixity of species, lowly forms to humans, special
creation
o Lamarck: genetic material can be changed in lifespan and passed to descendants
o Lyell
o Marthus: plants and animals produce more than can survive
o Darwin: origin of species, pangenesis
o Mendel: genes and pea plants
o Wallace: discovered evolution at the same time that Darwin did
o Rosalind Franklin: discovered the helical nature of DNA (Watson & Crick stole
her ideas)
Lecture 3
• Misconceptions about Evolution:
o Straw man argument
o Humans are pinnacle of evolution, evolution doesn’t explain the origin of life,
violates 2nd law of thermodynamics, eye too complex to have evolved randomly,
evolution can’t innovate, transitional fossils, Evolution can lead to social
Darwinism
• Taxonomy + Phylogenetics = Systematics
o Taxonomy: classify organisms based on similarities
o Phylogenetics: illustrate evolutionary relationship by constructing trees based on
characteristics of extant (not extinct) taxa
o Systematics: use of evolutionary relationships to group organisms into
hierarchical groups
o Phylogeny: true evolutionary history of group of organisms (tree = hypothesis)
o Clade: ancestor and all descendants (monophyletic group)
• Ancestral (primitive) character: already present in the evolutionary lineage leading to
group in question (context matters!!)
• Derived character: unique to group in question
• Characters primitive but extant species are NOT
• Building a Phylogenetic Tree:
o Groups united by shared and derived characters
o Least number of changes = most likely tree (maximum parsimony)
o Polytomy: node with > 2 branches (unresolved)
• Fossils and phylogeny reveal an evolutionary transition
o Evolution tinkers with existing parts to create new function
Lecture 4
• Biodiversity: how many and what kind of organisms live in a particular place/time
• Prokaryotes: bac†eria and archaea
• Eukaryotes: everything else
• Plants Water to Land transition: first green algae 470 million years ago (animals 450)
o Waxy outer covering, vascular system, pollen and seeds (gyno and angiosperms),
flowers
o Bryophytes: mosses, liver worms, hornworts, most primitive characteristics of
plants (resemble common ancestor)
o Ferns, lycophytes, horsetails: vascular tissue arises
o Gynosperms: seed plants, pollen travel by air, seeds travel by animal (conifers =
most abundant)
o Angiosperms: flowering plants surrounded by fruit and transported by animals,
most species diversity, live less densely than gynosperms
• Fungus: hyphae and mushrooms
• Cordyceps: fungal parasite in ants
• Animals Water to Land transition: complex multicellularity, heterotrophy, motility,
nerve cells and muscle cells (except sponges)
o Cambrian explosion: (541 million years) most animal phyla arose in ocean
o Out of water 450 million years ago
o Radial Symmetry: many planes of symmetry
o Bilateral Symmetry: single plane of symmetry, provide direction to the body, 3
embryonic tissue layers
▪ Cephalization: concentration of nervous system components at one end
of the body
• Wings evolved independently in 3 lineages of tetrapods pterosaurs, birds, bats
o Avoid predation, find prey, dispersal to new habitat
• Mammals are monophyletic:
o Hair or fur = insulation
o Mammary glands
o Endothermy
o Middle ear bones
Lecture 5
• Blending Inheritance: widely accepted, undermines theory of natural selection because
it eliminates variation
• Pangenesis: “gemmules” produced by cells throughout the body, carry info about body
part it came from, aggregate in the gametes for reproduction
o No evidence, acquired traits can be passed down
• Gene: unit of heredity segment of DNA that codes for proteins
• Chromosomes: long strand of DNA that contains many genes
o Wound up around some proteins
o As diploid organisms, we have homologous pairs of chromosomes (for each
locus, we have 2 alleles)
• Locus: location/position of a gene on a chromosome (often called a gene, Ex: eye color)
