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 .

•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.

This voyage lasted from 1831 to
1836.

“ Galapagos ” means turtle.
Many of
Darwin ’ s conclusions were based on observations of wildlife in the Galapagos
Islands .
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

• 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
.

• 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

• 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

• 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.

• 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.

M iddle Finger3. M utation
• 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

Thumb5. 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 lead to speciation. (Human induced) of traits are selected for?

WHAT IS
SPECIATION?
• Speciation:
The formation of new and distinct species in the course of evolution

• Allopatric Speciation
• Definition: new species evolves as a result of geographic isolation

• Sympatric Speciation
• Definition: new species evolves from single ancestor while living in same geographic niche
(organism’s “place” in ecosystem)

• Parapatric Speciation
• Definition: new species evolves as a result of partial geographic isolation as a result of occupying a new/different niche

• Divergent Evolution
• Definition: new species evolves from a common ancestor

• Convergent Evolution
• Definition: unrelated species become similar as they adapt to similar environments

• Parallel Evolution
• Definition: development of a similar trait in related, but distinct, species descending from a common ancestor

• 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

• 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

• Postzygotic Isolation
Horse
• Definition: reproductive isolation that occurs after two species have mated
• Example: hybrid mule offspring are infertile
Donkey
Hybrid = Mule
Can NOT reproduce

Embryology Stationa 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

• 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