Evolution. Evolution p. 369 Inherited change in organisms over time.
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Transcript of Evolution. Evolution p. 369 Inherited change in organisms over time.
Evolution
Evolution p. 369
•Inherited change in organisms over time
Definition: Evolution
• Scientific (more accepted now): the change in the relative frequency of alleles in a population
Did Darwin ever use the word evolution?
•NOPE
•He used instead “descent with modification”
Charles Darwin (1809-1882),
• In 1831, Charles Darwin sailed to the Galapagos Islands in the HMS Beagle.
• “Father of Evolution”
• Natural Selection
Alexander Oparin
• proposed that life began in the early oceans where a rich "primordial soup" of chemical compounds could build up. He suggested that energy from UV light and lightening could form these compounds.
Miller-Urey Experiment
Ammonia + nitrogen + methane + hydrogen + water + Voltage Voltage …after some time amino acids and organic compounds (BUT NOT LIFE) VIDEO of Miller Explaining
the Experiment
http://www.ucsd.tv/miller-urey/miller1.mpg
James Hutton: The Father of Modern
Geology
• The earth had to be much more than a few thousand years old (6,000) and more like millions.
• (ie., lava pushed up land for volcanoes)
Charles Lyell
• Principles of Geology
• The processes that occurred in the earth in the past still occur today.
Accepted Age of the Earth
• 4.5 - 4.6 billion years old
• LIFE AROSE
• 3.5 billion years ago
Lamarck (1744 -1829)• theory of
inheritance of acquired characteristics
• FALSE
Why do Giraffes have long necks?
Then according to Lamarck…
• Pass on longer necks.
• Or if you lift weights, your children will be big-muscled!
• BUT…
So…Lamarck was wrong!
•Passed-on-traits must be in the chromosomes in the sex cells
Malthus 1766-1834
Population would outrun food supply, leading to a decrease in food per person.
Darwin’s 5 Year JourneyDarwin observed and collected thousands of wildlife specimen he had never before encountered.
Galapagos Islands• Galapagos islands St
ock Footage and Video Clips. 39 Galapagos islands videos and movies available to search from over 20 royalty free motion brands.
H.M.S. Beagle
Galapagos: Off S.Am. Coast
Did Darwin know about genes?
•No•So what he compared were outward characteristics
Main Ideas of Darwin
• 1. The mechanism of evolutionary change was natural selection (survival of the fittest) –see Darwin’s finches
Darwin’s
Proposed mechanism for evolution = natural selection
Artificial Selection
• Bred to produce more meat Humans select
the variations they find useful
Natural Selection
• Also “Survival of the Fittest”
• Individuals that are better suited to their environment survive and reproduce most successfully
Orchids fool wasps into "mating" with them.
Natural Selection
•“Survival of the fittest”
Darwin's Theory of Sexual Selection
Natural Selection
• nature selected the best adapted varieties to survive and to reproduce.
• Video: Evolution: Library: Evolution of Camouflage
Why is this natural selection?
• Which color beetles’ genes are more likely to be passed on?
Natural Selection
• the driving force behind the process of evolution.
• “Survival of the fittest”
Elk Rivalry Animation Elk Rivalry
• Describe how natural selection works here.
• Opponents lock antlers
One extreme phenotype is most successful
Middle phenotype is most successful
Extreme phenotypes are most successful
English peppered moths• directional selection?
Does Natural Selection depend
• On genotype or phenotype?
•PHENOTYPE
VIDEO
• Evolution: How Does Evolution Really Work? Click on Video for Students
Fitness
• Ability of an organism to survive and reproduce in its specific environment
DESERT: Sleep in cool dens
Adaptations
Inherited characteristics that increases an organisms chance to survive
Big ears dissipate heat
Leafcutter carries 50x’s its weight
Western Grebe Courtship
• Western Grebe Courtship Movie
In the “rushing” display, the mating pair swim side-by-sidewith their wings held back, their long necks arched, and their yellow beaks angled upward.
Take the Blue-Footed Booby
Blue-Footed Booby Adaptations
• 1. Large webbed feet to propel in water at high speeds
Blue-Footed Booby Adaptations
• 2. Body and bill are streamlined
Blue-Footed Booby Adaptations
• 3. Large Tail to pull them out of a dive
Blue-Footed Booby Adaptations
• 4. Nostrils close so in a dive they won’t get water in their lungs
Blue-Footed Booby Adaptations
• 5. Specialized glands to manage salt intake and secrete oils
Chameleon: What adaptations?
Peacock LINK: Peacock Call
What adaptation did each beak allow it to eat these foods?
Do Beak Lab
• What effect does the size and shape of the bird’s beak have on the amount and type of food it can eat?
Darwin Agreed with:
•every species since the
first cells emerged from one common organism (probably some bacteria) = Common Descent
Tree of Life
• Links all living things
Geologic Time Scale
• BACTERIA
Common Descent
Common Descent
• theory of universal common descent = all organisms on earth are descended from a common ancestor.
Darwin thought the Galapagos finches descended from finches of
what country?
• Ecuador
We are more different than thought!
• Previous estimates of genetic similarity between humans and chimpanzees suggested they were 98.5–99% identical. However, after the sequencing of the chimpanzee genome 2005, the DNA similarity was fixed at 96%.
• Nature, the Chimpanzee Sequencing and Analysis Consortium, which is supported in part by the
National Human Genome Research Institute (NHGRI), one of the National Institutes of Health (NIH),
Factors Affecting Natural Selection
• Food supply
• Disease
• Unable to mate
• Weather natural selection
• Fitness of organisms
Where to find fossils?
• Most fossils are found in
sedimentary rock.
• Examples of sedimentary rock are limestone, shale, and sandstone.
Geologic Column
Sedimentary Layers)
Rod Sheldon:Rod Sheldon:
Historical Record of Organisms
• Youngest (on top) mammals/birds
• Next reptiles• Next amphibians• Next fish• Oldest (on bottom) prokaryotes
Assume that
• Sedimentary rock is laid down with the oldest rock layer on the bottom and the youngest rock layer on the top
Which is the most probable assumption about species A, B, and C
( In undisturbed rock layers)?1. Species B is more abundant than species C. 2. Species C existed before species B. 3. Species A and B are genetically identical. 4. Species B descended from species A.
ANSWER
#2 Species C existed before B
• When the industrial revolution arrived in England, the pollution had turned the bark of the trees a much darker color. Since light colored moths are much easier for birds to see on a dark background, they were preferentially eaten.
Some say this is not true!• 1. Moths fly at night (so color
would not be a factor).
• 2. Moths don’t land on tree trunks; they hang on upper canopy tree limbs.
Sexual Dimorphism
• Secondary sexual characteristics: color, size, etc. different in males and females
Main Ideas of Darwin
• 2. descent with modification
See “gradualism” and “punctuated equilibrium”
Descent with Modification: Hawaii honeycreepers
So…descent with modification
•Evolution is a remodeling process
•Do you agree?
Darwin’s Ideas (cont.)
• 3. Living species have arisen from earlier life-forms (common descent)
Common Descent Theories
• Phyletic Gradualism Punctuated Equilibrium
Phyletic Gradualism
• Gradual changes
• You would see transitional fossils (in-between forms)
Transitional Fossils (in-between forms)
Transitional Fossils
• The “missing link” or transitional forms may have features common to both species
Punctuated Equilibrium
• Speciation can occur very quickly, with long periods of little change (equilibria) in between.
• Proposed by Niles Elderidge and Stephen Jay Gould
Compare These
Several origins
How do we get “proof” of our ideas of evolution?
• Fossils
• Biogeography
• Comparative Anatomy
• Comparative Embryology
• Molecular Biology
Fossils
• Imprints or remnants of organisms that lived in the past
Also find in Tar Pits
• One of best finds of Pleistocene (1.8 million to 11,000 years ago) vertebrates in La Brea (Los Angeles)
Imprints (shape of organism embedded in soft soil)
• Fern Sycamore
More fossilsFish fossil
Crab
Horseshoe Crab
• Often referred to as a living fossil
• has remained unchanged for approximately 500 million years.
Frozen Fossil
Australopithecus afarensis
• Humans have much shorter arms compared to their legs than chimpanzees do, and Lucy falls roughly in the middle
Bones, teeth, shells preserve well
Jaw bone
Horn coral shell
Leg bone of amphibian
Petrified Wood
• Minerals dissolve in groundwater seep into the tissues of dead organisms and replace organic matter
Let’s Go...
Preserved: ice The world's oldest and best-preserved mummy (Oetzi), believed to be 5,300 years old
Shark tooth
Preserved: Amber fossil
• amber is the pitch of conifer trees
• This is a 95 million year old fossil insect
Trace Fossils
• 1. Tracks
• 2. Trails
• 3. Burrows
• Dino Foot
Dinosaur Tracks (Colorado)
My Favorite
• Coprolite
• Petrified Poop (Dung)
Healed Wolf Thigh Bone
Weathering Has Exposed Sedimentary Layers
• Utah
Lucy: Man or Ape?
Adult female - 25 yrs About 40% of her skeleton foundHer pelvis, femur (the upper leg bone) and tibia show her to have been bipedal. About 107 cm (3'6") tall(small for her species)About 28 kg (62 lbs) in weight.
Where did Lucy get her name?
• When the bones were found, the Beatles' song "Lucy in the Sky With Diamonds" was playing over during a night of dancing and drinking.
Dr. Donald Johanson recollects
• "I happened to glance over my right shoulder . . .and there on the surface of the ground was a little bit of an elbow, I recognized it immediately as belonging to a human ancestor.” (good eyes?)
November 30, 1974, in Hadar, Ethiopia.
Not A Human Arguments
• Lucy’s DNA found she was indeed an ape (Cell magazine)
-few skeletal bones which were usually fragmentary and often poorly preserved.-bones found far apart (1.5 miles away)
Other questions on Lucy
• Present day orangutan and spider monkeys have the same angle (pelvic and knees) as humans yet are extremely adept tree climbers.
And...
• Her brain size is still small, ape-like in proportion
• The jaw, in particular, is distinct in that it is V-shaped, totally unlike human jaws.
Population• Group of individuals of the
same species living in the same place at the same time.
What is...• The smallest unit that
can evolve?
•population
SPECIES
Similar -looking organisms that breed with one another and produce fertile offspring
SPECIATION
• Formation of a new species
Is a mule a new species?
•+
Did Darwin know about…
•Genes?
• No
Homologous Structures
• Different Function but Internal Anatomy is similar means same evolutionary origin
Biogeography
• Islands of the Galapagos were geographically isolated and the species of finches on these islands were different, also.
Homologous Structures
Pterodactyl
Bat
Bird
Compare Evolution Theories
• MODERN SYNTHESIS
• genes (alleles and mutations)
• phenotypes• populations (and
genetic drift)
• DARWINISM• Organisms• Speciation• Individuals.
Homologous Structures
Bat Mouse Humanwing forelimb arm
Embryology Compared
Haeckel’s Hoax"ontogeny recapitulates phylogeny".
Real Embryos Compared With Haeckel’s
Gills?
• In fact embryos never have true gills, and calling features of human embryos 'gill slits' is merely to read Darwinian theory into the evidence.
Comparative Molecular Biology: Number of Amino Acid
Differences with humans• Human 0
• Gorilla 1
• Gibbon 2
• Rhesus monkey 8
• Dog 15
• Horse, cow 25
• Mouse 27
DNA Cladistic Diagram
Molecular Biology Homologies:
• Similarities in blood, proteins and DNA and RNA sequences that indicate species relatedness; the greater the similarities, the more closely related two organisms are thought to be
Comparative Molecular Biology: Number of Amino Acid
Differences with humans• Human 0
• Gorilla 1
• Gibbon 2
• Rhesus monkey 8
• Dog 15
• Horse, cow 25
• Mouse 27
So organisms with similar DNA or proteins would be more closely related
Darwinian Fitness
• Contribution an individual makes to the gene pool of the next generation relative to the contribution of other individuals
Gene Pool
• The total collection of all genes in a population at one time.
Contrast• Microevolution
• Changes within a species
• EXAMPLE: humans are getting taller
• Macroevolution
• Species change into other species
• EXAMPLE: reptile into a bird
Microevolution
• Darwin did in fact observe small changes, such as changes in the size and shape of finch beaks etc.
Macroevolution?
• Darwin never did see a finch turn into an iguana or visa versa (or any other such major change).
• Major changes are theorized to take millions of years.