Transcript 15-Evolution

Chapter 15 – The Theory of Evolution
* This is the fundamental concept in Biology *
I.
Charles Darwin’s History
A.
1831-1836 HMS Beagle’s Naturalist
1.
He collected plants & animals from
around the world
2.
On the Galápagos Islands, Darwin
found species that are unique here
but similar to species elsewhere
3.
He hypothesized that species can
change over time
B.
1836-1856 Darwin tested his theory by
breeding domestic species using 
 Artificial Selection: breeding organisms
C.
with specific traits in order to produce
offspring with identical traits
1859 Darwin published his book:
“On the Origin of Species by Means of
Natural Selection”
 The Origin of Species films
 It caused arguments all over the world,
but sold out the very first day
II.
Definitions
A.
Evolution: change in population over time
B.
Population: a
group of organisms
of all the same
species, living in
the same place, at
the same time, that
can interbreed
III.
The Theory of Evolution
A.
Darwin’s observations (4 principles)
1.
Individuals in a population show
variations among others of the same
species.
2.
Variations are inherited.
3.
In nature, species produce more
offspring than can survive, but such
species don’t overrun Earth.
4.
Individuals struggle to compete in
changing environmental conditions;
Those that survive the competition
will pass on their traits to the next
generation.
B.
Darwin’s Conclusion:
1.
Natural Selection is the mechanism
for how evolution happens
2.
Natural Selection happens when
organisms with favorable variations
survive, reproduce, & pass their
variations to their offspring
 those with less-than-favorable
variations are less likely to survive
IV.
Support for Evolution – all organisms on Earth
have descended from a common ancestor(s)
A.
Fossil Records – show evolution patterns
1.
Derived Traits – newly evolved
features, such as feathers, that
don’t appear in fossils of
common ancestors
2.
Ancestral Traits –
primitive features, like
teeth and tails, that do
appear in ancestral forms
B.
Comparative Anatomy
1.
Homologous Structures –
anatomically similar structures
inherited from a common ancestor
2.
Analogous Structures – same
purpose, but not same construction
3.
Vestigial Structures – reduced forms
of functional structures (snake pelvis,
human appendix)
C.
Comparative Embryology – shared features
in vertebrate embryos with different adult
forms suggests a common ancestor
D.
Comparative Biochemistry – comparison of
similar amino acid sequences, DNA, and
RNA suggest common ancestry
E.
Geographic Distribution – plate tectonics
helps explain relationships seen in
organisms on different continents
Other Evolution
examples (videos)
V.
Evidence of Evolution – ADAPTATIONS that
develop in species over many generations
* Adaptation: a variation that helps organisms
survive in their environment
A.
Anatomical Adaptations
1.
Ducks have webbed feet for better
swimming
2.
Primates have opposable thumbs for
better grip
B.
Mimicry – one species resembles another
1.
Viceroy butterfly resembles
poisonous monarch
2.
Milk snake resembles venomous
coral snake
C.
Camouflage – species blends in w/ env.
D.
Physiological Adaptations:
a species changes how it operates
1.
Staph bacteria have adapted & can
no longer be killed by penicillin
2.
Evolution (CrashCourse)
Some insects & weeds can no longer
be killed by pesticides
Natural Selection (CrashCourse)
The Making of the Fittest