Download AP L1 Ch1 Evolution Slides Gensert

Evolution
Taxonomy
Domains
Prokaryotes vs Eukaryotes
Evolution – unifying theme in biology
Explains
Both similarities and differences
among living things
How groups of organisms are related
How organisms of the past
are related to organisms of the present
Evolution evidence: The Fossil Record
 Succession of forms
over time
 Transitional links
 Vertebrate descent
Fossil Record
How are these similar?
How do these differ?
Evolution evidence:
Comparative Anatomy
 Homologous
structures
(homology)
 Descent from a
common ancestor
Homologous structures
 Similar structure
 Similar development
 Different functions
 Evidence of close evolutionary
relationship
 recent common ancestor
Homologous structures
spines
leaves
succulent leaves
needles
colored leaves
tendrils
Vestigial organs
 Modern animals may have structures that serve little
or no function
 remnants of structures that were functional in
ancestral species
 deleterious mutations accumulate in genes for noncritical structures without reducing fitness



snakes & whales — remains of pelvis & leg bones of walking
ancestors
eyes on blind cave fish
human tail bone
Analogous structures
 Separate evolution of structures
similar functions
 similar external form
 different internal structure & development
 different origin
 no evolutionary relationship

Don’t be fooled
by their looks!
Solving a similar problem with a similar solution
Evolution evidence:
Comparative Embryology
 Pharyngeal
pouches, ‘tails’ as
embryos
Evolution evidence:
Cytological Evidence
Evolution Evidence:
Molecular
DNA – genetic code
DNA
RNA
(1)
transcription
Proteins
(2)
translation
ATP – energy currency
Evolution evidence:
Molecular
• Similarities in
DNA, proteins,
genes, and gene
products
• Common genetic
code
Closely related species have sequences that
are more similar than distantly related
species
 DNA & proteins are a molecular
record of evolutionary relationships
Mechanisms of Evolution
LAMARCK
LAMARCK:
(1) Trait acquired
(2) Acquired trait passed on to offspring
WEISMAN
Weisman:
(1) Cut off mice tails for 18 generations
(2) All subsequent generations had tails
(3) “Disproved” the 2nd part of Lamarck’s idea;
“Acquired” traits are NOT passed on to offspring
Charles Darwin
 1809-1882
 British naturalist
 Proposed the idea of
evolution by natural
selection
 Collected clear evidence
to support his ideas
Voyage of the HMS Beagle
 Invited to travel around the world
 1831-1836 (22 years old!)
 makes many observations of nature

main mission of the Beagle was to chart
South American coastline
Stopped in Galapagos Islands
500 miles off coast of Ecuador
But Darwin found… a lot of finches
Darwin was amazed to
find out:
All 14 species of birds
were finches…
But there is only one
Finch?
Large Ground
species of finch on theFinch?
Finch
mainland!
Sparrow?
Small Ground
Sparrow?
QuickTime™ and a
Photo - JPEG decompressor
Finch
are neede d to see this picture.
How did
one species
of finches become
so many different
species now?
Woodpecker?
Warbler Finch
Woodpecker?
Warbler?
Veg. Tree Finch
Warbler?
Darwin’s finches
 Differences in beaks (recall freshman bio lab)
 associated with eating different foods
 survival & reproduction of beneficial adaptations to
foods available on islands
Warbler finch
Cactus finch
Woodpecker finch
Sharp-beaked finch
Small insectivorous
tree finch
Large
insectivorous
tree finch
Small ground
finch
Cactus
eater
Medium
ground finch
Insect eaters
Seed eaters
Vegetarian
tree finch
Bud eater
Large
ground finch
Darwin’s finches
 Differences in beaks
allowed some finches to…
 successfully compete
 successfully feed
 successfully reproduce

pass successful traits onto
their offspring
Essence of Darwin’s ideas
 Natural selection
 variation exists in populations
 over-production of offspring

more offspring than the environment can support
 competition

for food, mates, nesting sites, escape predators
 differential survival

successful traits = adaptations
 differential reproduction

adaptations become more
common in population
More observations…
Correlation of species
to food source
Whoa,
Turtles, too!
ssence of Darwin’s ideas
 Natural selection
 variation exists in populations
 over-production of offspring

more offspring than the environment can support
 competition

for food, mates, nesting sites, escape predators
 differential survival

successful traits = adaptations
 differential reproduction

adaptations become more
common in population
 Evolution:
Evolution
the change over time of the
genetic composition of
populations
 Natural selection:
populations of organisms
can change over the generations if
individuals having certain
heritable traits leave more
offspring than others (differential
reproductive success)
 Evolutionary adaptations:
a prevalence of inherited
characteristics that enhance
organisms’ survival and
reproduction
November 24, 1859
Natural selection in action
 Insecticide &
drug resistance
 insecticide didn’t
kill all individuals
 resistant survivors
reproduce
 resistance is inherited
 insecticide becomes less &
less effective