Transcript EVOLUTION NOTES

Essential Questions: What is evolution?
What types of evidence supports the
theory of evolution ?
Evolution- changes in species
over long periods of time
Geologic Time-Earth’s history and
revealed by layer of rock (4.5 billion).
Fossil Record-collection of fossils
that provide clues to the history of
earth’s organisms.
Evidence of Evolution
Fossils- remains or
traces of organisms
that once lived.
Dino Humor
Essential questions: What is comparative anatomy?
What are homologous structures ?
Comparative Anatomy-comparing body
structures of plants and animals.
Homologous structures:
 Similar in structure but different in function.
Exs. Wing of a bat and flipper of a whale.
 Indicates a common ancestor
Comparative Anatomy
Comparative Anatomy
Comparative Embryology -comparing the
similarities among vertebrate embryos. Exs.
Chicken/fish/man—gill slits 2-chambered
heart, tail
Comparative Embryology
Comparative Biochemistrycomparing chemicals in organisms.
Exs. Blood, DNA
Lion and cats are closely related
because of similarities in protein
structures.
Theories of Evolution
Spontaneous
Generation- a.
concept that living
things came from
nonliving things
Exs. Toads come
from mud (flies
from rotting
animals)
b. Disproved by
Louis Pasteur.
Theory of Use and
Disuse-Lamarck
–
•
Proposed in the early 1800’s by Jean Lamarck
.
– Theory states that organisms were able to
develop new structures because they needed
the structures.
Size of an organ is determined by how much the
organism used. Exs. Ballet dancers, basketball
players
Theory of Use and Disuse
Lamarck also believed in the
“inheritance of acquired
characteristics”. A trait produced in
an individual’s lifetime can be passed
on to its offspring. This was
disproved in that late 1800’s by
August Weismann.
Weismann’s Experiment
Charles Darwin
Darwin’s Finches
Essential Question? What is Darwin’s
theory of Natural Selection?
Theory of Natural Selection:
• Theory proposed by naturalist
Charles Darwin in the 1850’s.
• Stated evolution occurs
because of natural selection.
• Nature(environment) acts as the
selecting agent of an organism’s
trait.
Theory of Natural Selection
Theory contains the
following main
concepts:
• Overproduction
Theory of Natural Selection
• Competition-for food,
habitat, mate, light,
etc.
Theory of Natural Selection
• Variations-members of a
population show
differences in traits that
make certain individuals
better adapted to survive.
Exs. Size, color, structure
• Survival of the fittest
• Natural Selection
variations that are more
helpful are a natural
selection agent against
organisms that can’t
adapt.
• A population evolves not
the individual
 Adaptive Value-any
trait that helps the
organisms survives
and reproduces under
a given set of
environmental
conditions. Ex.
Coloration of rabbits.
Essential Question: What is the modern theory of
evolution
1. Mutation Theory -Hugo DeVries.
.
a. Inherited mutations
cause variations
b. Mutations occur randomly and those that
are favorable are passed on to offspring.
2. Modern Theory -combined Darwin’s ideas
of variation, natural selection with mutations,
DNA, chromosomes, and sexual
reproduction.
Genetic Shufflingsorting and random
recombination of
genes during meiosis
and fertilization. Ex.
Shuffling of cards.
Essential Question: What are some examples of
evolution in our time?
Evolution in our Time:
• Exs. Black flies in the
Adirondack Mountain
Revenge of the Black Fly
Examples of Evolution in Our Time
• Staphylococcus
bacteria that is
resistant to
antibiotics.
• English peppered
moth for over 100
years in Manchester
England.
Essential Questions: What is geographic and
reproductive isolation? How does it affect speciation?
Geographic Isolation:
Occurs when population is physically
separated into a smaller populations by
geographic barriers.
 Geographic Barriers: Exs. Mountains
ranges, desert, rivers, shopping, malls.

Geographic Barriers
• Speciationproduction of a new
species.
• Reproductive
isolation-population
can’t interbreed even
if barriers are
removed. Exs. Kaibab
and Albert squirrels in
the Grand Canyon
Adaptive radiation-process by which
many new species of organisms evolved
from a common ancestor. Ex. Finches of
the Galapagos Islands.(13 different
types).
Darwin’s Finches
Patterns of Change:
• Changes in species are often related to
•
•
environmental change.
Species with short reproductive cycles that
produce many offspring tend to evolve more
quickly than species with long lifespan and few
offspring.
The failure to adapt to a changing environment
may result in the death of the species.
More Dino Humor
Time Frame for Evolution:
 While the essentials of Darwin’ theory of
evolution, variation and natural selection are
generally accepted by the scientific community,
considerable discussion exists within this
community as to the time frame in which
evolution occurs.
 The current theories have been proposed to
explain the time frame:
Gradualism
Punctuated Equilibrium
Gradualism
Gradualism
Evolutionary change is
slow, gradual and
continuous.
Supported by fossils
that show slight
changes between
adjacent rock layers
and greater amounts
of change between
bottom and top layers
Punctuated Equilibrium
Punctuated Equilibrium:
1. Proposes that species
have long periods of
stability (several million
years) interrupted by brief
periods of significant
changes during which
new species may evolve.
2.Supported by fossil
records that there is very
little change, but sudden
bursts of changes are
observed between some
adjacent layers.
Gradualism Versus Punctuated
Equilibrium
Gradualism Versus Punctuated
Equilibrium
Essential Question: What is the heterotroph
hypothesis?
Heterotroph Hypothesis-explanation for how the
early life forms may have evolved on the primate
earth.
Steps in the Process of Formation of the Earth:
 Earth is composed of a sea of hot thin soup,
containing N2, CO2, NH3, H2 and H20.
 Energy from the sun and radioactive sources
caused the formation of organic compounds.
 Eventually these compounds became able to
reproduce and use CO2, anaerobic bacteria.
 These bacteria evolved into aerobic bacteria and
could undergo photosynthesis. Ex. Blue-green
algae
Miller’s Experiment