Download Evolution

Evolution
• spontaneous generation (abiogenesis) –
the idea that life comes from nonliving things
Redi –
experimented with meat in jars, one
covered with cheesecloth; maggots appeared
in open jar
Redi’s experiment
Spallanzani –
experimented with broth in flasks,heated
both, put a stopper in one; stoppered one
stayed clear, open one became cloudy
*Pasteur –
experimented with 2 flasks with broth
heated, bent the neck into S-shape on
one; open one became cloudy
*finally disproved spontaneous generation
Spallanzani’s experiment
Pasteur’s experiment
biogenesis –
the idea that life comes from living things
Oparin –
hypothesized that organic compounds
formed in warm seas and energy from the
sun or lightning allowed the compounds to
form more complex molecules to form the
first organism
Miller –
tested Oparin’s hypothesis in the lab
Earth’s first atmosphere
Miller’s experiment
1st organism is thought to be a bacterium –
• prokaryotic
• asexual
• heterotrophic
• anaerobic
• evolution –
a change over time
Charles Darwin developed currently accepted theory of
evolution of life on Earth from common
ancestry (common descent)
Evidence for evolution
1) fossil record (Geologic time scale) –
collective history of Earth’s climate and
organisms
fossil – preserved remains of ancient
organisms
4.5 billion years – estimated age of Earth
paleontologists – scientists who study
fossils
Fossils
Evidence for evolution
2) homologous structures –
structures which originate from the same
body region
ex: human arm and bat’s wing
vestigial structures –
structures once necessary in ancestral
forms, but no longer needed today
ex: appendix, coccyx, wisdom teeth
Homologous structures
Vestigial structures
Evidence for evolution
analogous structures –
structures which perform a similar task
ex: fly wing and bird wing
3) comparative embryology –
embryos of similar organisms have very
similar early development indicating similar
DNA at work
Analogous structures
Embryological similarities
Evidence for evolution
4) biochemical similarities –
comparing protein structure in all organisms
to find similarities & differences
Biochemical similarities
Natural Selection
Darwin –
developed the idea of natural selection –
organisms with favorable traits are more
likely to survive and reproduce;
“survival of the fittest”
Natural Selection
fitness –
combination of physical traits and
behaviors that allow an organism to be
more successful in its environment
adaptation –
any inherited characteristic that increases
an organism’s fitness for survival
Natural Selection
Darwin –
developed the idea of natural selection –
organisms with favorable traits are more
likely to survive and reproduce;
“survival of the fittest”
fitness –
combination of physical traits and behaviors
that allow an organism to be more
successful in its environment
Natural Selection
Lamarck –
thought acquired traits could be passed
on to future generations
ex: giraffe neck length
Natural Selection
Peppered moth (Biston betularia)
In the 1800’s in Manchester, England these
moths lived in tree groves. Two varieties were
seen: a speckled (peppered) moth due to a
dominant allele & a black moth due to a
recessive allele.
Before Industrial Revolution
Natural Selection
Before the Industrial Revolution, lichen-covered
trees were light in color, dark moths were eaten
more.
After the Industrial Revolution, lichens absorbed
soot & tree bark became dark in color, light
moths were eaten more.
After Industrial Revolution