Download UNIT IV EVOLUTION

UNIT IV: EVOLUTION AND
BEHAVIOR
QUESTION: DO PLANTS AND
ANIMALS EVOLVE?
Gary Larson
PREHISTORIC EARTH
Modern (1900+): Earth 4 billion years old; Life began 3.8
billion years ago.
Before 1800: Earth few thousand years old; Life created
at specific times and doesn’t change
Fig. 27.6
1800’s: great intellectual shift in thinking
1
Fossil link between birds and reptiles
Archaeopteryx
http://tiktaalik.uchicago.edu/meetTik.html
Jean-Baptiste de Larmarck
1744-1829
•One of first biologists to believe evolution does occur
•Studied invertebrates (fossils)
•Inheritance of acquired characteristics (Published 1809)
2
Charles Darwin
•HMS Beagle in 1831
•Evidence he found:
•Earth is very old
•Species change over time
•Common ancestry
Age 31
Descent with
Modification
Galapagos finches
3
Descent with Modification
•Origin of Species (1859)
•Theory of Natural Selection
•Individuals vary in their traits (physical
characteristics passed on through
reproduction)
•Members of a population compete for
resources
•“survival of fittest”
•Populations change over time--best
adapted survive
•Depends on environment (nature)
•No genetics; not teleological (nothing
predetermined)
Darwin vs. Lamarck
Theory
Of Natural
Selection
Inheritance
Of Acquired
Characteristics
4
Inherit the Wind (1960)
•“Scopes Monkey Trial”
•1920’s Tennessee
•John Scopes, Clarence Darrow, William Jennings Bryan
•1968 law taken off the books
Microevolution--Darwin with genetics
•Change in gene frequencies
in a population over time
•Population: all the members
of a single species that
occupy a particular area at
one time and interbreed and
exchange genes
•Hardy-Weinberg Principle-allele frequencies will remain
constant in a population
•If they change-evolution
has occurred
Peppered Moth-”industrial melanism”
Fig. 27.13.b
5
Genetic Drift
•A cause of microevolution
•Change in allele frequencies due to chance
(genotype frequencies don’t follow Punnett Squares!)
•Affect smaller populations more
Fig. 27.14
Founder Effect
•Rare alleles occur at
higher frequency in a
population isolated
from general
population
•Amish in Lancaster,
PA
•Polydactylism and
Fig. 27.15
dwarfism
6
Co-evolution
•Two species exert selective pressures on each other and
adapt
•Predator-prey relationships
•Bumblebees and flowers
•Mimicry is extension of co-evolution
Monarch butterfly
Viceroy butterfly
Natural Selection
--process by which organisms with the
most favorable phenotypes reproduce
more and pass on those traits
•A driving force behind evolution
•Selective pressure by environment
•“survival of the fittest”
•Acts on phenotype to change allele frequencies
•Acts on individuals in a population to eventually
change the population as a whole
7
Darwin
Modern Evolutionary
Theory
Requirements for Natural Selection
1. Variation
2. Inheritance
3. Overproduction
4. Differential Reproductive Success
Natural Selection--Antibiotic
Resistance
•Used against bacteria since 1928
(Alexander Fleming--penicillin)
•Great genetic variability (mutations)
•Most bacteria die; some live (short
treatment by Ab)
•“maladapted” bacteria reproduce
•Repeat exposure to Ab increases
resistance
•Widespread use and misuse of Ab
•MRSA-methicillin resistant
staphylococcus aureus
•WASH YOUR HANDS!!!
8
Figure 27A
Stabilizing Selection
•Most common
•Average individuals
selected (no
extemes)
•Intermediate
phenotype
•Lowers frequency of
“undesirable alleles”
•Human birth weight
Fig. 27.16
9
Directional Selection
•Extreme phenotype (allele with greater fitness)
•Adapting to changing environment
•Ab resistance (TB)
•Horses, peppered moth, sickle cell Fig. 27.17
Speciation
What is a Species?
•Similar physical traits
•Interbreed (shared gene pool)
•Reproductively isolated (no gene flow)
•Dogs, cats, corn, dolphins, chimps
How does speciation occur?
Fig. 27.21
•One species
two species
•Geographic isolation, then reproductive
isolation
•Genetic drift, natural selection, etc
•Mass extinction (punctuated
equilibrium)
•Slow and steady (phyletic gradualism)
10
What’s in a name?
TAXONOMY--Classification of living organisms
•Hierarchical (become more specialized)
•Domain, kingdom, phylum, class, order, family, genus,
species (mnemonic)
•Carolus Linnaeus(1707-1787)
•Based on physical characteristics
•Binomial nomenclature-- Homo sapiens
•Modernized and modified
•Domain concept introduced 1990
•Phylogenetics (1960’s)--Darwinian common descent
Name that organism!
1. Canis familiaris
2. Canis lupus
3. Escherichia coli
4. Bufo bufo
5. Ginkgo biloba
6. Haliaeetus leucocephalus
7. Ursus horribilis
8. Felis catus
9. Toxicodendron radicans
10. Strigophilus garylarsonii
11
Three Domain Classification System
Eukaryotic
EUKARYA
Prokaryotic
BACTERIA
ARCHAEA
Fig. 27.23
Six Kingdom Classification System
1. Plant:
2. Animal:
3. Fungi:
– cell type
– # of cells
– food?
–reproduction
4. Protists:
5. Bacteria:
6. Archebacteria:
12
Phylogenetics
--timescale of evolution-latest
earliest
•Cladogram (evolutionary
tree)
Traditional
1.mammals
2.turtles
3.snakes/lizards
4.crocs/dinos/birds
*
*
*
*
* common ancestor
junction
Cladistic
*
1.mammals
2.turtles
3.snakes/lizards
4.crocodiles
5.dinosaurs/birds
*
*
*
*
13
The Animal Kingdom
1.
2.
3.
4.
5.
6.
Level of Organization
Symmetry
Body Plan
Body Cavity
Segmentation
Jointed Appendages
5
3&4
2
1
The Green Sheet
or
How are humans related to other
organisms evolution-wise?
Multicellular
bilateral symmetry
complete digestive
system
endoskeleton
warm-blooded/hair
placental
opposable thumb
bipedal
still living
14
Plant and Animal Behavior
What is Behavior?
Plant Behavior
Phototropism
GROWTH
•Light
•Day length
•Gravity
•Touch
Negative Gravitropism
15
Animal Behavior
• Animals have brains (BIG difference
from plants!)
•Learning (change in behavior through
experience)
•Innate (instinct--knowing how to
respond without prior exposure to the
stimulus)--essential to life and survival
•Genetic and environmental influences
•Complex interactions between all the
body’s systems (hormonal, biochemical,
senses, neuromuscular system)
Learned Behavior
Imprinting
•
•
•
•
•
Baby ducks, geese follow first moving object
Instinctive (natural selection--recognition of kin)
Narrow window of time for it to occur
Hard-wired (genetic; follow anything)+ learning
Konrad Lorenz (Nobel Prize Med. Physio. 1973)
Classical Conditioning
•
•
•
•
Associative learning
Pavlov’s dogs
Learned behavior because of stimulus
Advertising
imprinting
Operant Conditioning
•
•
•
B.F.Skinner
Rewards; positive reinforcement
Stimulus-response gets stronger
Operant conditioning
16
Innate Behavior
http://www.cals.ncsu.edu/course/ent425/tutorial/Behavior/index.html
Reflex
• Basic unit of innate behavior
• Neural pathway: sensory neuron
motor neuron
Orientation Behavior: coordinated movements (walking,
swimming, flying) in response to an external stimulus
•
Taxis
1) Dorsal light reaction
•
Fixed Action Pattern (FAP)
1) Praying Mantis
2) Courtship displays, hunting, nest-building
3) Attack or escaped behaviors
4) Behavioral cascade
How is Behavior Adaptive?
1. Feeding Behavior
• Black Heron and minnows
• Garter snakes
2. Reproductive Behavior
• Sexual selection
3. Anti-Predator Behavior
• Monarch and Viceroy
• Hoary marmot (Alaska)
• Meerkat
ADAPTIVE BEHAVIOR=CONTINUATION OF THE SPECIES
17