Chapter 24/25 Evidence of Evolution Geological, Anatomical, Chemical, Molecular Dodo bird.
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Transcript of Chapter 24/25 Evidence of Evolution Geological, Anatomical, Chemical, Molecular Dodo bird.
Chapter 24/25 Evidence of Evolution
Geological, Anatomical, Chemical, Molecular
Dodo bird
Evidence Supporting Evolution Artificial selection
human-caused evolution
Fossil record transition species
Anatomical record homologous & vestigial structures embryology & development
Molecular record protein & DNA sequence
Artificial Selection Artificial breeding can use variations in
populations to create vastly different “breeds” & “varieties”
“descendants” of the wolf
“descendants” of wild mustard
‘Natural’ Selection in Action Insecticide &
drug resistance insecticide didn’t
kill all individuals resistant survivors
reproduce resistance is
inherited insecticide
becomes less & less effective
Fossil Record Layers of sedimentary rock contain fossils
new layers cover older ones, creating a record over time
fossils within layers show that a succession of organisms have populated Earth throughout a long period of time
Fossil Record
Charles Lyell (1797-1875) studied the Temple of Scrapis (Sicily) built on land & used until 200 AD high tide now above temple floor erosion in columns well above high tide
Meaning: In less than 2000 years, temple sunk well below sea level, and then was raised up again — natural processes and immense periods of time could produce great changes.
“the present is the key to the past”
Geologist give us time for evolution…
Fossil Record A record showing us that today’s
organisms descended from ancestral species
Evolutionary Change In Horses
Millions of years ago
50
100
150
200
250
300
350
400
450
500
550
60 55 50 45 40 35 30 25 20 15 10 5 0
Equus
HyracotheriumMesohippus
Merychippus
Nannippus
Bo
dy
siz
e (
kg
)
Evolution of Birds
Smithsonian Museum, Washington, DC
Archaeopteryx lived about 150 mya links reptiles & birds
??
??Where are the
Intermediates?
Land Mammal
Vestigial Organs Hind leg bones on whale fossils
Why would whaleshave pelvis & leg bones
if they were alwayssea creatures?
Vestigial Organs Modern animals may have structures
that serve little or no function remnants of structures that were
functional in ancestral species evidence of change over time
some snakes & whales show remains of the pelvis & leg bones of walking ancestors
eyes on blind cave fish
human tail bone
This is not LaMarck’s loss from “disuse”!
Anatomical Record Homologous structures
similarities in characteristics resulting from common ancestry
Homologous Structures Similar structure Similar development Different functions Evidence of close
evolutionary relationship recent common ancestor
Homologous Structures Forelimbs of human, cats, whales, & bats
share same skeletal structures similar structure similar embryological development different functions evidence of common ancestor
branched off from common 4-limbed ancestor
2006 Fossil Discovery of Early Tetrapod “missing link” from sea to land animals
YOUR INNER FISH!
Analogous Structures Separate evolution of structures
similar functions similar external form different internal structure &
development different origin no evolutionary relationship
Solving a similar problem with a similar solution
Don’t be fooledby their looks!
Convergent Evolution Flight evolved in 3 separate animal groups
evolved similar “solution” to similar “problems”
analogous structures
Does this mean they have a
recent common ancestor?
Convergent Evolution Fish: aquatic vertebrates Dolphins: aquatic mammals
similar adaptations to life in the sea
not closely related
Those fins & tails & sleek bodies are
analogous structures!
Parallel Evolution Parallel, but separate, evolutionary paths
filling similar ecological roles in similar environments, so similar adaptations were selected
but are not closely related
marsupial mammalsmarsupial mammals
placental mammal
s
placental mammal
s
Parallel EvolutionNiche Placental Mammals Australian Marsupials
BurrowerMole
Anteater
Mouse
Lemur
Flyingsquirrel
Ocelot
Wolf Tasmanian “wolf”
Tasmanian cat
Sugar glider
Spotted cuscus
Numbat
Marsupial mole
Marsupial mouse
Anteater
Nocturnalinsectivore
Climber
Glider
Stalkingpredator
Chasingpredator
Comparative Embryology Similar embryological development in
closely related species all vertebrate embryos have similar
structures at different stages of development gill pouch in fish, frog, snake, birds, human, etc.
Molecular Record
0 25 50 75 100 1250
25
50
75
100
Millions of years ago
Horse/donkey
Sheep/goat
Goat/cow
Llama/cow
Pig/cow
Rabbit/rodent
Horse/cow
Human/rodent
Dog/cow
Human/cow
Human/kangaroo
Nu
cleo
tid
e su
bst
itu
tio
ns
Comparing DNA & protein structure universal genetic code!
DNA & RNA compare common genes
cytochrome C (respiration) hemoglobin (gas exchange)
Closely related species have sequences that are more
similar than distantly related species
DNA & proteins are a molecular record of evolutionary relationships
Why comparethese genes?
cytochrome c from 33 species
Comparative Hemoglobin Structure
100 20 30 40 50 60 70 80 90 100 110 120
LampreyFrogBirdDogMacaqueHuman
328 45 67 125
Number of amino acid differences betweenhemoglobin (146 aa) of vertebrate species and that of humans
Why does comparingamino acid sequencemeasure evolutionary
relationships?
Globin Gene Family Tree looking at the DNA sequences of the different globins can show approximate time of divergence
Evidence of Evolutionby Natural Selection
Using Molecular Evidence to check
Testable Hypotheses
Genome Sequencing What can data from whole
genome sequencing tell us about evolution of humans?
Primate Common Ancestry?
Chromosome Number in the Great Apes
(Hominidae)
orangutan (Pogo)
48gorilla (Gorilla)
48chimpanzee (Pan)
48human (Homo)
46
Hypothesis:Change in chromosome number?
If these organisms share a common ancestor, then is there evidence in the genome for this
change in chromosome number?
Chromosomal FusionTestable prediction:
If common ancestor had 48 chromosomes (24 pairs),then humans carry a fused chromosome (23 pairs).
Centromere
Telomere
Ancestral Chromosomes Fusion Homo sapiens
Inactivated centromere
Telomere sequences
Chromosome Number in the Great Apes
(Hominidae)
orangutan (Pogo)
48gorilla (Gorilla)
48chimpanzee (Pan)
48human (Homo)
46
Testing the Human Genome
“Chromosome 2 is unique to the human lineage of evolution, having emerged as a result of head-to-head fusion of two acrocentric chromosomes that remained separate in other primates. The precise fusion site has been located in 2q13–2q14.1, where our analysis confirmed the presence of multiple subtelomeric duplications to chromosomes 1, 5, 8, 9, 10, 12, 19, 21 and 22. During the formation of human chromosome 2, one of the two centromeres became inactivated (2q21, which corresponds to the centromere from chimp chromosome 13) and the centromeric structure quickly deterioriated.”
“Chromosome 2 is unique to the human lineage of evolution, having emerged as a result of head-to-head fusion of two acrocentric chromosomes that remained separate in other primates. The precise fusion site has been located in 2q13–2q14.1, where our analysis confirmed the presence of multiple subtelomeric duplications to chromosomes 1, 5, 8, 9, 10, 12, 19, 21 and 22. During the formation of human chromosome 2, one of the two centromeres became inactivated (2q21, which corresponds to the centromere from chimp chromosome 13) and the centromeric structure quickly deterioriated.”
Hillier et al (2005) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.
Human Chromosome #2 shows the exact point at which this
fusion took place…
Chr 2
Ancestral Chromosomes Fusion Homo sapiens
Inactivated centromere
Telomere sequences
Well I’llbe a monkey’s…or an ape’s…uncle? Cousin?
Wait – what does this mean?
In case you had any doubts…
On the left is a copy of the human
chromosome ‘set’.
On the right is the respective
chromosome for the chimpanzee—our nearest cousin
outside our species
Building “Family” Trees Closely related species (branches) share same line of descent until their divergence from a common ancestor more like evolutionary “bushes”
Archaebacteria&
Bacteria
Classification Old 5 Kingdom system
Monera Protists Plants Fungi Animals
New 3 Domain system Bacteria Archaebacteria Eukaryotes
Protists Plants Fungi Animals
Prokaryote
Eukaryote
Linnaen Nesting
KPCOFGS not used so
much more as phylogenetics developed
Phylogenetic Trees
Plant Diversity
Bryophytesnon-
vascularland plants
Pteridophytesseedless vascular plants
Gymnospermpollen & “naked” seeds
Angiospermflowers &
fruit
seed plants
vascular plants
mosses ferns
conifers flowering plants
colonization of land
synapomorphies
Cnidaria
Platyhelminthes
sponges jellyfish flatworms roundworms
Nematoda
Mollusca Arthropoda Chordata
Annelida Echinoderm
mollusks
multicellularity; diploblastic
Ancestral Protist
tissues
bilateral symmetry; triploblastic
body cavity
segmentation
Porifera
Animal Diversity
coelom
starfish vertebratessegmentedworms
insectsspiders
backbone
protostomes deuterostomes
synapomorphies
Any Questions??
put peppered moth in lab 17
Peppered Moths Dark vs. light variants
Year % dark % light1848 5 951895 98 21995 19 81
Peppered Moths What was the selection factor?
early 1800s = pre-industrial England low pollution lichen growing on trees = light colored bark
late 1800s = industrial England factories = soot coated trees killed lichen = dark colored bark
mid 1900s = pollution controls clean air laws return of lichen = light colored bark
industrial melanism