Phylogeny Review

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Phylogeny Review

• District AP Biology Session

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Evolution

• is the change in a population over time
• Lamarck was the first to have a widely accepted
  theory of evolution
• Acquired characteristics use and disuse
• Example Giraffes needed long necks to get food,
  so each generation stretched its neck and passed
  the longer neck to the next generation (until the
  necks became quite long).

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Darwin and natural selection

• Book On the origin of Species
• Each offspring produces more offspring than can
  survive
• Offspring compete for limited resources
• Organisms in every population vary (different
  traits)
• Traits tend to be heritable
• The individuals with the most favorable traits
  are most likely to survive, reproduce, and pass
  these traits to offspring

Question 6, 31
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Support for Evolutionary Theory

• paleontology fossils
• distributions of plant and animal populations
  around the world
• ontogeny recapitulates phylogeny Gould
• comparative anatomy
• Molecular biology DNA sequencing, amino acid
  analysis, use of mitochondrial DNA

Question 19-22
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Comparative Anatomy
Question 14, 25

• Analogous structures- same function, but evolved
  independently (fly and bird wing)
• Homologous structures similar structures with
  different functions

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Variation

• Genetic variability no two individuals are
  alike
• How did we get it?
• Gametogenesis and fertilization
• Crossing over during meiosis
• New alleles only through mutation!

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Population GeneticsHardy-Weinberg

• Relative allele/genotype frequencies are stable
  over time
• Example
• The allele for red flowers (R) are dominant to
  white flowers (r)
• Green pods can be RR or Rr
• Yellow pods must be rr
• Assign p to the frequency of one allele (R) and q
  to the frequency of the other (r)

Question 7
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• The sum of the frequencies must
• be one
• p q 1
• If you know the frequency of one allele, then you
  know the other
• The sum of the frequencies of the genotypes must
  also be one
• p2 2pq q2 1

genotype Frequency explanation
RR p2 Needs 2 R
Rr 2pq 2 ways to get R and r
rr q2 Needs 2 r
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Hardy-Weinberg Equilibrium5 conditions

• Need a large population
• No mutations can occur within the population
• No immigration or emigration (gene flow)
• Mating must be random
• No natural selection
• The above conditions, when met, assure a stable
  population.
• If any of the above conditions are not met,
  changes in allele frequencies occur causing
  evolution!

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Genetic Drift

• Random increase or decrease in alleles
• Founder effect type of genetic drift where a
  small number of individuals move to a new
  location (immigration) and populate the new
  location

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• Bottleneck effect another type of genetic drift
  when the population undergoes a dramatic decrease
  in numbers. The small group left behind is
  subject to genetic drift.

Question 33
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Modes of evolution

• Divergent evolution 2 or more species
  descending from a common ancestor
• Convergent evolution 2 unrelated species with
  similar traits living in the same type of
  environment

Question 17
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Types of selection

• Directional a phenotype at an extreme is
  favored, very few of the other extreme are
  present
• Stabilizing organisms at the extremes are
  weeded out favoring the common phenotype
• Disruptive Favors both extremes, opposite of
  stabilizing

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Speciation

• Allopatric interbreeding within two populations
  is prevented by a geographic barrier
• Sympatric formation of a new species without a
  geographic barrier
• Geographic isolation
• Behavioral isolation
• Temporal isolation
• Adaptive radiation many species from one where
  multiple niches are open

Questions 1, 18, 27
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(No Transcript)
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Types of macroevolution
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Urey Miller experimentOrigins of organic
molecules
Question 30
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Figure 25.7 Hierarchical classification
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Figure 25.12 Cladistics and taxonomy
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Figure 26.16 Our changing view of biological
diversity
Question 16
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Figure 27.2 The three domains of life
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History of the Kingdoms
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Phylogenyevolutionary relationships

• Taxonomy classifying organisms based on their
  traits
• Taxa from most inclusive to least inclusive
• Domain Do
• Kingdom Kings
• Phylum Play
• Class Chess
• Order On
• Family Fancy
• Genus Gold
• Species Stools?

Question 28
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Taxonomy
Question 4

• Binomial nomenclature scientific name Genus
  species
• Problems -
• Different systems of classification
• Changes as we learn more about biology
• Now we can use DNA, and amino acids similarities
  to group organisms

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Kingdom Monera

• Are prokaryotes
• Single, circular DNA molecule
• No histones
• Reproduce asexually by binary fission
• Exchange DNA in conjugation, transformation, or
  transduction
• May contain plasmids
• Classified by
• Size
• Shape
• Habitat
• Metabolism
• Energy sources

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Figure 27.5 Gram-positive and gram-negative
bacteria
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ArcheabacteriaDomain - Archeae

• Cell walls lack peptidoglycan (gram negative,
  smooth)
• Ribosomes more like those of eukaryotes
• Extremophiles live in harsh environments
• Methanogens produce CH4
• Thermophiles heat loving
• Halophiles salt loving

Question 2
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Kingdom EubacteriaDomain Bacteria

• Largest class of prokaryotes
• Cell walls with peptidoglycan
• Gram positive
• Many different kinds
• Nitrifying
• Cyanobacteria
• Decomposers
• Pathogens
• Some do nitrogen fixation
• (important part of nitrogen cycle)

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Other classifications

• Shape
• Cocci
• Bacilli
• Spirilli

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Table 27.1 Major Nutritional Modes
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Table 27.2 A Comparison of the Three Domains of
Life
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Protista

• Eukaryotes
• Most are unicellular (some are multicellular or
  in colonies)
• Very diverse
• Classified base on nutrition
• Plant-like (autotrophes)
• Animal-like (heterotrophes)
• Fungus-like (decomposers)

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Plant-like

• Euglenophyta Euglena are both photosynthetic
  and predatory
• Dinoflagellata have 2 flagella
• Chrysophyta golden algae
• Chlorophyta green algae
• Phaeophyta brown algae, seaweeds
• Rhodophyta red algae
• Bacillariophyta diatoms, cell walls of silica

Question 26
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Animal likeProtozoans

• Zoomastigina move by flagella, Trychonympha in
  termite guts and Trypanosoma parasites
• Rhizopoda amoebas, eat by phagocytosis
• Ciliophora move by cilia, paramecium
• Sporozoa nonmotile and spore-forming,
  plasmodium (malaria)
• Foraminifera produce CaCO3 porous shells

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Figure 28.1a Too diverse for one kingdom Amoeba
proteus, a unicellular "protozoan"
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Figure 28.3 Euglena an example of a
singlecelled protist
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Figure 28.17 Diatoms Diatom diversity (left),
Pinnularia (left)
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Fungus-likeMyxomycota

• Large multinucleated masses
• Slime molds
• Some spore
• Some produce gametes that can fuse to form
  diploid zygotes

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Kingdom - Fungi

• Multicellular
• Heterotrophes
• Cell walls composed of chitin
• Parasites, pathogens, and decomposers
• Classified based on reproductive structures
• Zygomycota
• Ascomycota
• Basidiomycota
• Deuteromycota

Question 3, 15
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Absorption of nutrients

• Mycelium composed of hyphae
• Hyphae are long branches of cells that secrete
  enzymes
• Food is digested externally then absorbed by
  hyphae

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Figure 31.4 Phylogeny of fungi
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Figure 31.7 The life cycle of the zygomycete
Rhizopus (black bread mold)
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What is an animal?

• Multicellular
• Heterotrophs
• No cell walls, cells held together by structural
  proteins (collagen)
• Unique tissues nervous and muscular
• Most reproduce sexually
• Probably evolved from a colonial, flagellated
  protist

Question 29
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Early embryonic development
Question 32
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Traditional phylogeny based on body-plans
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All animals with tissues develop from germ layers

• Ectoderm surface of the embryo
• Outer covering of animal
• Central nervous system if present
• Endoderm innermost layer
• Lines digestive tube
• Forms liver, lungs, digestive organs
• Mesoderm middle layer
• Muscles and most other organs
• Not present in Cnidarians or Ctenophors

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Whats a coelom?

• Coelom mesoderm-lined body cavity fluid-filled
  space separating the digestive tract and outer
  body wall
• Acoelomates
• Solid bodies, no cavity
• Phylum Platyhelminthes
• Pseudocoelomates
• Cavity not lined by mesoderm tissue
• Phylum Nematoda and Rotifera
• Coelomates
• Have a true coelom
• Functions of a body cavity
• Fluid cushions the suspended organs
• Hydrostatic skeleton
• Organs grow and move independently of outer body
  wall

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Coelomates are either protostomes or deuterostomes

• Coelomates are divided based on their embryonic
  development into
• Protostomes
• Mollusks
• Annelids
• arthropods
• Deuterostomes
• Echinoderms
• chordates

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Protostome vs Deuterostome
Question 23-24
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Invertebrate Phyla Overview

• Porifera
• Cnidaria
• Ctenophora
• Platyhelminthes
• Rotifera
• Nemertea

• Mollusca
• Annelida
• Nematoda
• Arthropoda
• Echinodermata
• Chordata (primarily vertebrates)

Question 8-12
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Porifera

• Sessile
• No nerves or muscles, but individual cells can
  react to the environment
• Filter feeders
• Spongocoel central cavity
• Osculum large opening
• Choanocytes generates water current and traps
  food in collar of cell
• Hermaphrodites each individual produces both
  sperm and eggs
• Can reproduce asexually through regeneration

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Figure 33.3 Anatomy of a sponge
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Cnidaria

• Radial symmetry
• Lack mesoderm
• Gastrovascular cavity with single opening that
  functions as mouth and anus
• Two body plans polyp and medusa
• Carnivores
• Nematocysts stinging capsules insode cells
  called cnidocytes
• Nerve net
• Hydra, jellyfish, sea anemones, corals

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Figure 33.4 Polyp and medusa forms of cnidarians
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Platyhelminthes

• Flatworms
• Triploblastic ectoderm, endoderm and mesoderm
• One or no body opening (nutrients diffuse across
  body surface of tapeworm)
• Acoelomates with a gastrovascular cavity
• Planaria, flukes, tapeworms

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Figure 33.10 Anatomy of a planarian
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Figure 33.13 A rotifer
Rotifers are pseudocoelomates with jaws, crowns
of cilia, and complete digestive tracts. Some
reproduce by parthenogenesis females produce
more females from unfertilized eggs
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Molluska

• 3 main body parts
• Muscular foot used for movement
• Visceral mass contains most organs
• Mantle secretes a shell
• Coelomates
• Feed using radula organ scrapes up food
• Chitons, Gastropods (snails, slugs), Bivalves
  (clams, oysters) and cephalopods (squids,
  octopuses, nautiluses)

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Figure 33.16 Basic body plan of mollusks
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Table 33.3 Major Classes of Phylum Mollusca
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Annelida

• Segmented worms
• Coelomates
• More complex organ systems
• Closed circulatory system
• Metanephridia excretory tubes that remove wastes
  and discharge it through skin pores
• Hermaphrodites that cross fertilize by exchanging
  sperm
• Earthworms, polychaetes, leeches

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Figure 33.23 Anatomy of an earthworm
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Nematoda

• Roundworms
• Pseudocoelomates
• Covered by tough cuticle (exoskeleton)
• Complete digestive tract
• No circulatory system
• Sexual reproduction
• Decomposers, nutrient cyclers, parasites
• Trichinella spiralis

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Arthropoda

• Coelomates
• Segmented bodies
• Exoskeltons
• Jointed appendages
• Exoskeleton made of protein and chitin, anchor
  site for muscles, mvmt onto land, molting
• Sensory organs
• Open circulatory systems hemolymph is pumped by
  a heart into sinuses
• Gas exchange through gills, internal tracheal
  systems, or book lungs

Question 5
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Table 33.5 Some Major Arthropod Classes
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Phylum Echinodermata

• The only invertebrate, nonchordate deuterostomes
• Sessile or slow moving
• Spiny skin
• Water vascular system branches into tube feet
  used in locomotion, feeding, gas exchange
• Larvae have bilateral symmetry, adult radial
  symmetry is an adaptation to sessile lifestyle
• Sea starts, sea urchins, sand dollars, sea
  cucumbers

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Figure 33.38 Anatomy of a sea star