Transcript Evolution - Wylie ISD

Evolution
Definition: The process when the overall
POPULATION change over time.
Natural Selection
Definition: The process whereby organisms
better adapted to their environment tend to
survive and produce more offspring.
Adaptation
A change or process of change by which an
organism or species becomes better suited
to its environment.
Evolution act at the level of
POPULATION
Natural selection at the level of
INDIVIDUAL
Mimicry
Definition: The phenomenon whereby
unprotected prey species gain protection from
predators by mimicking toxic or other wise
protect species.
Evolution
People &
Theories
Charles
Darwin
1809-1882
•The Father of Evolution
•Born in 1809, England
•Sailed on the HMS Beagle
•During his voyage, he
made
observations that led him
to his THEORY OF
EVOLUTINON.
Darwin’s THEORY OF
EVOLUTION:
• a scientific explanation for the
diversity of life, by proposing how
modern organism evolved from
common ancestors.
This voyage lasted from 1831 to
1836.
Many of
Darwin’s
conclusions
were based on
observations
of wildlife in
the Galapagos
Islands.
“Galapagos” means
turtle.
The Galapagos
Islands lie 500 miles
west of Ecuador in
the Pacific Ocean,
directly on the
equator.
After returning from the
Galapagos and studying
different types of plants &
animals he collected during
the voyage, Darwin
concluded that organisms
change over time….
Darwin called this…
which means change in species
over time
Jean Lamarck
• French scientist, who in 1809
proposed a hypothesis for how
organisms change over
generations.
• believed that over the lifetime of
an organism, physical features
would increase or decrease in
size because of either the use
or disuse of the feature.
• changes would then be passed
on to offspring, enabling species
to
change over time.
Lamarck had correctly identified that a
change is a species is linked to an
organism’s environmental condition.
Thomas
Malthus
• Wrote an essay in 1798 that
said if the human population
grew unchecked, there
wouldn’t be enough living
space and food for everyone.
• Malthus said that the forces
that controlled population
growth included war, disease
natural disasters and famine
Alfred Wegener
• Most well known for
his Continental
Drift hypothesis
(1912), which led
to the modern
science of plate
tectonics.
In 1910, upon examining a new map that included
African and South American coastline research data,
Alfred noticed that depth features for corresponding
coastline contours of the two continents matched, but did
not have time to think about it much until later, in 1911,
when he read paleontological evidence of creatures
existing on the two continents that could not possibly
have crossed the vast ocean distances.
https://www.youtube.com/watch?v=TzzGPfVx32M
Macroevolution
• Refers to major evolutionary changes over time, the origin of new types of
organisms from previously existing, but different, ancestral types.
• Examples of this would be fish descending from an invertebrate animal, or
whales descending from a land mammal.
Microevolution
• Refers to varieties within a given type.
• Change happens within a group, but the
descendant is clearly of the same type as
the ancestor. This might better be called
variation, or adaptation, but the changes
are "horizontal" in effect, not "vertical."
• Changes might be accomplished
by "natural selection," in which a trait
within the present variety is selected as
the best for a given set of conditions, or
accomplished by "artificial selection," such
as when dog breeders produce a new
breed of dog.
Pinky- 1. Population Size
• Small population allows chance to take over.
Ring Finger: 2. Non- Random Mating
• Organisms choose mate based on physical features and
location.
Middle Finger- 3. Mutation
• Mutation, change in a DNA/gene, can
affect frequency of gene pool.
Pointer Finger- 4. Movement/Migration
• Gene flow: Movement of individual into an areal will
change the gene frequency
– Immigration: individuals moving into an area
– Emigrate: individual moving out of an area
Thumb- 5. Adaptation
• Natural selection
– Favors individuals with traits that are suitable for the
environment (thumbs up)
– Selects against individuals with traits that are unfit for the
environment. (thumbs down)
Main Types of Selection Pressures
• Stabilizing Selection
– Natural selection favors the average for
population selected
• Directional Selection
– Natural selection favors one extreme of the
population for that trait
– often happens when environment changes in a
consistent way- e.g.climate gets colder.
• Disruptive Selection
– Natural selection favors both extremes selected
– Causes species to diverge
Artificial Selection
The intentional breeding for certain traits, or
combinations of traits, over others… this can What types
of traits are
lead to speciation. (Human induced)
selected for?
WHAT IS
SPECIATION?
• Speciation:
The formation of
new and distinct
species in the
course of evolution
TYPES OF SPECIATION
• Allopatric Speciation
• Definition: new species
evolves as a result of
geographic isolation
TYPES OF SPECIATION
• Sympatric Speciation
• Definition: new species
evolves from single
ancestor while living in
same geographic niche
(organism’s “place” in
ecosystem)
TYPES OF SPECIATION
• Parapatric Speciation
• Definition: new species
evolves as a result of partial
geographic isolation as a
result of occupying a
new/different niche
TYPES OF EVOLUTION
• Divergent Evolution
• Definition: new species evolves from a
common ancestor
TYPES OF EVOLUTION
• Convergent Evolution
• Definition: unrelated species become
similar as they adapt to similar
environments
TYPES OF EVOLUTION
• Parallel Evolution
• Definition: development of a similar trait in
related, but distinct, species descending
from a common ancestor
TYPES OF EVOLUTION
• Coevolution
• Definition: influence of closely associated
species on each other in their evolution
ANALOGOUS STRUCTURES
• Definition: structures present in different
organisms that have the same function but
are structurally different and have different
origins
HOMOLOGOUS STRUCTURES
• Definition:
structures present
in different
organisms that
have the same
underlying
structure but may
have different
functions
TYPES OF ISOLATION
• Prezygotic Isolation
• Definition:
reproductive isolation
preventing a zygote
• Example:
geographic,
behavioral,
mechanical
Geographic Isolation
• When a population is divided
into two or more smaller
populations due to
PHYSICAL BARRIERS.
• This can occur when rivers
change course, mountains
rise, continents drift, or
organisms migrate.
Example: Northern Spotted Owl
and Mexican Spotted Owl
Behavioral Isolation
• Two species do not mate because of
differences in courtship behavior.
Example: Blue footed boobies (mating dance),
birds (mating song), nocturnal versus diurnal
TYPES OF ISOLATION
• Postzygotic Isolation
Horse
Donkey
• Definition:
reproductive isolation
that occurs after two
species have mated
• Example: hybrid mule
offspring are infertile
Hybrid = Mule
Can NOT reproduce
Embryology Station- a science which is about the
development of an embryo from the fertilization of the
ovum to the fetus stage
Sort the cards into their correct location in
the chart then answer questions.
Embryology
Comparative Anatomy
(Homologous structure)
study of the body structures of different
species of animals in order to understand the
adaptive changes they have undergone
Read and compare the anatomical
structures of different species and answer
the questions.
Molecular Biology- study of biology at a
molecular level
Compare the Hox gene sequences between different
species and answer the questions.
Cladogram- a chart that shows an
organism's evolutionary history
Study the cladogram and answer the related questions.
Biogeography- study of
geographical distribution of
organisms
What is evolution?
Definition: Change in the allele frequency of
a population over time.
Allele Frequencies
• The amount of an allele in a population
– “B”
– “b”
How does a population change over time?
• Genetic Drift– When the allele frequencies of a population is changed due
to randomness or chance. –Reduce genetic variation
How does a population change over time?
• Gene Flow
– When alleles travel from one
population to another
population of the same
species. -
Migration
Genetic Drift vs. Gene Flow
• https://www.youtube.com/watch?v=Q6JEA2olNts
Beetles Modeling Lab
• Objective: Observe how gene flow and genetic drift can affect the allele
frequencies of a population.
Bottle Neck
• When a population’s
size is reduced for at
least one generation
due to catastrophic
event.
Example: Northern
elephant seal
Founder Effect
• Occurs when a new
colony is started by a
few members of the
original population.
Example: Polydactyl in
Amish communities
Cladograms
Cladograms are used to…
• Organize organisms based on
evolutionary relationships (phylogeny).
• In other words… who is related to who
and where did we come from…
How are cladograms constructed?
• Organisms are grouped together based on their
shared derived characteristics (trait modified
from the ancestral trait).
What do you know?
• Using the cladogram,
which animals have
claws/nails? (Hint: 4)
• Which animals have
fur/mammary glands?
(Hint 2)
• To what is the chimp
most closely related to?
• Look at the
cladogram at the
right. What
conclusions can
be drawn about
the relationship
between humans
and chimps?
Image courtesy of http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_05
How to read a Cladogram
• This diagram shows a
relationship between 4 relatives.
These relatives share a
common ancestor at the root of
the tree.
• Note that this diagram is also a
timeline. The older organism is
at the bottom of the tree.
• The four descendents at the top
of the tree are DIFFERENT
species. This is called
SPECIATION.
Image courtesy of http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_05
• Branches on the tree
represent SPECIATION, the
formation of a new species.
• The event that causes the
speciation is shown as the
fork of the “V”.
Image courtesy of http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_05
• Species B and C each have
characteristics that are
unique only to them.
• But they also share some
part of their history with
species A. This shared
history is the common
ancestor.
Image courtesy of http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_05
• A CLADE is a group of
organisms that come from a
common ancestor.
• If you cut a branch of the
tree, you could remove all
the organisms that make up
a CLADE.
Image courtesy of http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_06