Download Evolution

Evolution
How species change over time
Charles Darwin &
Natural Selection
• “Survival of the fittest” which
means those best adapted to
their environment survive,
reproduce & pass on their genes
• So “fittest” means best adapted,
NOT the strongest
Adaptation
GAMETES:
egg &
sperm
• Any trait an organism has that helps it survive
• What are some adaptations of this falcon?
Fossils of Ancient Lobsters
220 million years ago
190 million years ago
Similar Structures
Insects wings are not
alive
Bird Wings are alive
Comparative
Embryology
• insects & animals that have VERY similar
development are closely related
• All vertebrates have VERY similar development
= common ancestor
8-9 wks
Comparative Embryology
Vestigial Structures
ORGAN THAT IS NO
LONGER USED
appendix in humans
legs in snakes
Congo snake
BIOCHEMICAL EVIDENCE
The more exact
codons in a
sequence the
more related
organisms are
• Comparison of macromolecules (proteins, nucleic
acids, lipids, carbs) between organisms
• Ex. comparing eukaryotic ribosomes to prokaryotic
ribosomes
DO you think we still find and
identify NEW species?
http://www.youtube.com/watch?v=ZDI3RexF0UM&feature
=em-subs_digest
What is a Species?
• Group of the same organisms
• Live together
• Mate a produce viable offspring; means
the babies can have babies of their
own
Horse + donkey = Mule
Mules are
STERILE
meaning, they
CAN’T have
babies!
Causes of Variation
• Genes have 2 forms (dominant and recessive)
• Polygenetic traits (multiple variations; hair/eye color, skin…)
• Complex genetics (codominance, multiple allele, sex-linked
traits, incomplete dominance)
• Mutations-changes of the DNA of genes
• Can be bad (disease) or good (immunity to malaria)
• Mutation can cause immunity (pesticide resistant plants,
antibiotic resistant bacteria)
How Species Evolve over
Time
AKA SPECIATION
Directional Selection
Woodpecker beaks
homozygote
•When one extreme phenotype has the best chance
to survive
•As a result, the frequency (number) of those with
that phenotype shift over time
Evolution of the horse
• DIRECTIONAL
selection
• Using the diagram as
evidence, how did the
horse evolve over
time?
• Hypothesize why these
changes could have
happened.
Directional selection
• roadrunner
Most run from
enemies!
Stabilizing Selection
• heterozygote
When the intermediate phenotype
has the best chance to survive
Disruptive Selection
• When both extreme phenotypes have the
best chance to survive
• center: left snail = aa right snail = AA
What type of selection?
• What does
“mimic” mean?
Other Causes of
Speciation
Mutation of DNA
• Immunity to Malaria in Africa
• AA=smooth normal cells =die from
Malaria
• Aa=bumpy cells =immune to Malaria
• aa=sickle-cell shape =die from either
malaria or sickle-cell
Sickle Cell Anemia
red blood cells
Geographic Isolation
• Mountains, islands,
etc. keep a population
isolated
• Means species
changes and evolves
into new species
Geographic Isolation Leads
to adaptive radiation, which
is when one species
evolves into many over time
due to competition of
habitat or food!
• Lemurs of
Madegascar
• 2 different groups of
mammals
Variation
• Differences in phenotype
with in 1 gene
• Example: eye color in
humans
• Brown eyes are
naturally protected
from suns glare
Variation
Coevolution
• When one species evolves because of
the presences of another species
• Ex. Flowers and insects
• Flowers pollinated by hummingbirds
often have a narrow, tubular shape
Coevolution
stop after insect pollinators
http://www.youtube.com/watch?v=4YQ5q1cjEU4
Honey
bee
• summary darwin natural selection song
http://www.youtube.com/watch?v=tfYqD7gT6YA
Drug resistant Bacteria
• A few bacteria will be naturally immune
to drug.
• They DON’T die, but reproduce
spreading the immunity until most
bacteria are immune.
• Ex. dimatap, vicks 44D, zyterc were
perscription drugs: now over the
counter.
Classification
• Taxon is the latin name for
group!
• The classifications begin with
the largest groupings and move
down to the smallest (Kingdom>->species)
• Taxon, Kingdom, Phylum, Class,
Order, Family, Genus, Species
• Easy way to remember-King
Phillip Came Over For
Grandma’s Spaghetti!!
Scientific Name
• The Genus species
of an organism
• Always written in
italics (ex. Homo
sapiens are humans)
• Only species are
able to interbreed!
Phylogenetic Tree
• Shows evolutionary
relationship between
organisms
• Can help tell which
organisms are more
closely related than
others
Phylogenetic Trees
• Which organism is most
closely related to man?
______ How do you
know?
• Which organism is man
more closely related: Whale
or Dimetrodon?
____________________
• How do you know?
Cladogram
Shows relationships up close-characteristics
they share
• Which group is most
closely related to ?
1. Echinoderms?
2. Annelida?
•
Which Least related
to?
4. Porafera?
Dichotomous Keys
• A key that helps to identify an organism
• Uses questions to lead you to the
scientific name of the organism
• By looking at features of the organism,
the key will help you to figure out what it
is!
Follow Steps to find out what organism #3 is? #7?