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.