Download AIR Evolution/Taxonomy Review

Levels of Classification
• Most living things have been classified based on
their physical and behavioral characteristics.
• There are 7 levels of classification:
Kingdom-Phylum-Class-Order-Family-GenusSpecies
• The kingdom level is the most broad and the
species level is the most specific. There are 6
kingdoms- Archaebacteria, Eubacteria, Protists,
Fungi, Plants and Animals.
• Living things are typically referred to using their
genus and species names. Humans are Homo
sapiens. Homo is our genus name and sapien is
our species name.
Dichotomous Key
• If you don’t know the classification of a species,
you can use the clues of a dichotomous key to help
you.
Populations
• A population is a group of organisms of the same
species that inhabit the same area at the same
time.
• Most populations grow either exponentially or
logistically.
• Exponential growth occurs when resources are
plentiful and the reproduction rate is greater than
the death rate.
• Logistic growth occurs if there are limited resources.
Growth of the population plateaus when its carrying
capacity is reached.
• The number of organisms will continue to hover
around the carrying capacity (will go above it and
below it and above it and below it …).
What is the Carrying Capacity for this
population of rabbits?
Population Genetics
• The genetics of a population will remain stable unless
one or more of the following events occur.
• Mutation= random changes in the DNA
• Natural Selection= survival of the fittest(certain
genotypic groups are targeted because they are not
able to survive as well as others)
• Gene Flow= movement of alleles into or out of a
population (immigration or emigration)
• Genetic drift= changes in the alleles of a population
due to random events (i.e. natural disaster or
epidemic)
• Non-random mating
• Small population size= Allele frequencies change
more drastically in small populations.
Each colored line
represents a different
genetic drift event acting
on a population.
Notice that the smallest
population experiences
the greatest change in
allele frequency over time
and the largest population
experiences the least
change in allele frequency
over time.
Measuring the Genetics of a Population
• The Hardy-Weinberg equation calculates genetic
variety in a population.
• The H-W equation is:
p2 + 2pq + q2= 1 (or 100%)
q2= the frequency of homozygous recessive
individuals.
2pq = the frequency of heterozygous individuals.
p2= the frequency of homozygous dominant
individuals.
If the allele frequencies change from 1 generation
to the next, the population has evolved.
Human Impact on Populations
Humans can impact populations in a variety of
ways:
• Selective breeding
• Deforestation
• Pesticide and fertilizer use
• Invasive species
• Antibiotics
• Burning fossil fuels/global warming
Evidence of Common Ancestry
• Charles Darwin came up with the theory that all
living things can be traced back to the same
original ancestor.
• The evidence that supports this theory includes:
– Fossils
– DNA/proteins
– Embryo structure
– Comparative anatomy (homologous features)
– Vestigial structures
Fossils
Embryos
Homologous Features
Vestigial organs
Cladogram
• A cladogram is a diagram that shows the
evolutionary relationship among different
species.
• As an organism evolves, there is a new branch
on the cladogram.
• Organisms with similar characteristics (DNA,
structure, behavior) are placed more closely
on the cladogram.
• Characteristics that evolve between species
are called derived characters.
Variations of Cladograms
Human
Macaque
Dog
Bird
Frog
Lamprey
8
32
45
67
125
0
10
20 30 40 50 60 70 80 90 100 110 120
Create a Cladogram using the Pictures
Place a “+” if the characteristic is present and a “-” if it is absent
Organism
Characteristic
Jaws
Turtle
Gorilla
Human
Lamprey
Caecilian
Lamprey
Cat
TOTAL
Limbs
Hair
Lungs
Opposable
thumb
Upright, erect
posture