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DNA is very important
Or
How it can change the world
Pedigree symbols
What is the phenotype of the
offspring of individuals 1 and 2?
2
1
3
4
5
What about 4, 5, and 6?
6
What do you know about the
genotypes of individuals 1 and 2?
1
2
Sometimes, they look like this:
Half-filled
circles/ squares
represent
carriers, or
heterozygous
genotypes.
Karytopye – picture of all
chromosomes
Shows chromosome abnormalities
Down Syndrome
Turner Syndrome
Klinefelter Syndrome
Cri-Du-Chat
Jacobs Syndrome
Mutations: the good, the bad, and
the indifferent
• Point mutations
• Frame-shift mutations
• Not all mutations are bad – some make
bacteria ANTI-BIOTIC RESISTANT.
Good for the bacteria, not-so-good for you!
• Some mutations result in no change
Mutations are changes in DNA
• Changes in DNA result in changes in the
protein.
• Changes in the protein can introduce new
characteristics (blonde hair)
• New traits can be passed to offspring
Mutations can change a population
• If new traits are advantageous, those
individuals will have more offspring with
the new traits.
• Over long periods of time, these
populations can become new species.
• Species are defines as groups that can
breed with each other and produce
VIABLE offspring.
This is Natural Selection.
New species can develop if…
• Members of a populations are separated
from each other (GEOGRAPHIC
ISOLATION)
• Members of two populations stop breeding
with each other (REPRODUCTIVE
ISOLATION)
• Having an abnormal number of
chromosomes (POLYPLOIDY)
Divergent Evolution
• One ancestral species leads to 2 new
species
Marine
Iguana
Land
Iguana
Ancestral
Green Iguana
Adaptive Radiation
• One ancestral species leads to 3 or more
new species
Gradualism or Punctuated
Equilibrium?
• Two ideas of how new species develop
Gradualism: lots of small changes in DNA
over long periods of time
Punctuated Equilibrium: fewer, larger
changes over long periods of time.
Gradualism
10 million years
Punctuated Equilibrium
10 million years
Notice the results of both are the same:
CHANGE
A cladogram is like a family tree
showing how things have changed.
Shows
relationships
based on
specific
characteristics
Point
where
common
ancestors
diverged
Everything to the
right of this point
have Vertebrae
Phylogenetic tree shows
relationships between organisms.
Each “split”
represents
a common
ancestor
A type of Cladogram that shows the relationships
between organisms with a common ancestor
Living things are grouped
according to similarities
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Kingdom
Phylum
Class
Order
Family
Genus
Species
Largest
Smallest
Binomial Nomenclature: scientific names are Genus and
Species
Ex. Iguana iguana
Living things are grouped
according to similarities
• Homologous structures (homo=same) VS
Analogous structures (not the same, but
same function)
- bird wings and
bat wings
-bird wings and
insect wings
Living things are grouped
according to similarities
• Embryology
Organisms that have
similar embryonic
development are more
closely related
Dichotomous keys
• Species can be identified using a
dichotomous key
• Series of “either / or” questions leading to
the identification.
Dichotomous keys
Example:
1. Does the flower have white
or yellow petals?
-if yellow, it is a sunflower
-if white, go to question 2
2. Does the flower have a
yellow or red center?
-if yellow, it is a daisy
-if red, go to question 3