evolution: natural selection, mutations, information

History of Darwin

In 1831, Charles Darwin set sail on the HMS Beagle on a 5 year voyage around the world. He served as a naturalist (scientist who studies nature), and kept detailed notes of his findings. On the Galapagos Islands, Darwin noticed that the finches on one island were similar, but not identical to the finches on another island.

History of Darwin

The large ground finch has a heavy, strong beak for cracking large seeds.

The cactus finch has a tough beak that is good for eating cactus and nectar.

The warbler finch has a small, pointed beak - good for poking into cracks to get small insects.

History of DarwinWhy are the finches different on each island?

Start with the parent generation of finches. The parents have several baby finches. Some of them have larger beaks, some of them have smaller beaks, just like the pea plants (some are tall, some are short.)

Each island has a different food supply.Island #1: only has big, hard seeds. Which babies will do the best on island #1?

History of DarwinIsland #2 has no seeds, but has lots of insects

who like to hide in cracks in rocks and logs.

Which babies do you think would do best on island #2?

On island #1, the small beak babies would die, leaving only big-beaked finches. When those big-beaked finches have babies, what kind of babies do you think they will have?

History of DarwinOn island #2, the small-beaked babies would

thrive, and the big-beaked finches would die.What kind of beaks will the the babies of the

small-beaked finches have?

On each island, we see a change in the population of finches because of the difference in available food.

What happens to the “big-beak” genes on island #2 with the ants?

History of Darwin What happens to the “small-beak” genes on island #1

where the only food are the large seeds?

On both islands:Nature has selected the best beak.

“Natural Selection:” a process where animals (or plants) with favorable traits survive, and animals without those traits die.

“Survival of the fittest:” those who are the strongest, or best equipped for the environment survive. They pass their genes down to their offspring.

What is Natural Selection? Before natural selection takes place, dogs have lots of

genetic variety. Some of them are big, some are small. Some are faster, some are better diggers, etc…


genetic variety. Some of them are big, some are small. Some are faster, some are better diggers, etc…Some of them are born with thick fur, some are born with

short, thin hair.



short, thin hair. The population of dogs move to a place where it is much

colder.



short, thin hair. The population of dogs moves to a place where it is much

colder. What will happen to the dogs with short, thin hair?




colder.What will happen to the dogs with short, thin hair?Which dogs are “naturally selected” to carry on their genes

to their puppies?




colder. What will happen to the dogs with short, thin hair?Which dogs are “naturally selected” to carry on their genes

to their puppies?

Which gene is passed on, and which gene is lost?

What is Natural Selection?Note:

They are now adapted to their environment.

What is Natural Selection?This has

occurred through natural selection.

What is Natural Selection?There have

been no new genes added.

Genes have been lost.

What is Natural Selection?The dogs are

less able to adapt to future evironmental changes. If the climate were to become hot, there is no genetic information for short hair, so the dogs would probably overheat.

What is Natural Selection?So we see that

natural selection is not an information-gaining process, but an information-losing process.

Natural selection is different than large-scale evolution.

Large Scale Evolution:

Textbook’s definition: Evolution is the process by which populations accumulate inherited changes over time.

The theory of evolution states that all life arose from a single cell over 3.7 billion years ago.

What is Large-Scale Evolution? (Macroevolution)

• Evolution states that the first cell was assembled through random movements in random chemicals and amino acids bumping into one another and forming a simple cell that began to make copies of itself.


• According to the theory, this new population of cells were able to absorb nutrients, process the nutrients to create usable energy (ATP), repair broken parts of themselves, and replicate themselves using this energy.

• Scientists have been trying to build a machine that will do this…

Self-repairing, Self-replicating Machines

A self-replicating machine would need to have the capacity to gather energy and raw materials, process the raw materials into finished components, and then assemble them into a copy of itself. Further, for a complete self-replication, it must, from scratch, produce its smallest parts, such as bearings, connectors and delicate and intricate electronic components. It is unlikely that this would all be contained within a single structure, but would rather be a group of cooperating machines or an automated factory that is capable of manufacturing all of the machines that comprise it.The factory could produce mining robots to collect raw materials, construction robots to assemble new machines, and repair robots to maintain itself against wear and tear, all without human intervention or direction. The advantage of such a system lies in its ability to expand its own capacity rapidly and without additional human effort.

http://en.wikipedia.org/wiki/Self-replicating_machine

Self-repairing, Self-replicating Machines

This is one of the biggest problems with the theory of evolution – the first cell – the beginning of life.

We’ve learned that each cell is just as complex (if not MORE complex) than a modern city.

Evolution theory states that this city was accidentally assembled through the random movement of chemicals bumping up against one another.


• Over the next 3.7 billion years or so, these simple cells gradually became more and more complex until we have all of the plants, trees, animals and humans we see today.

Going From Simple to Complex

• How do you go from simple to complex?

• How much information is needed to build a trash can?

How much information is needed to build a skyscraper?

Information

• To go from random chemicals to a giant sequoia tree, A LOT MORE information is needed, and NEW information is needed.

• Where did the information come from?

• Where do you get MORE information, and where do you get NEW information?

• Evolutionary theory teaches that this has been achieved through mutations in the DNA code.

• Evolution says that mutations in DNA make MORE information, and NEW information.

Going From Simple to Complex

Quotes about DNA:

• Francis Crick (co-discover of DNA’s structure):– “[DNA] sequence is a code for the amino acid

sequence of a particular protein.”

• Bill Gates (founder of Microsoft):– “DNA is like a computer program but far, far more

advanced than any software ever created.”

What Are Mutations, and Do They Create MORE and NEW Information?

• Mutation: A copying error during DNA replication.

• Are mutations ever helpful,

like with antibiotic resistant bacteria?


• Environmental agents such as nuclear radiation can damage DNA by breaking the bonds between oxygens (O) and phosphate groups (P).


• Mutations also result when the DNA polymerase makes a mistake, which happens about once every 100,000,000 bases.

Actually, the number of mistakes that remain incorporated into the DNA is even lower than this because cells contain special DNA repair proteins that fix many of the mistakes in the DNA that are caused by mutagens. The repair proteins see which nucleotides are paired incorrectly, and then change the wrong base to the right one.


• Imagine a wireless transmission of a secret message gets sent to a spy:

• The teacher’s tie is a confetti bomb.

• But another spy scrambles the message by shooting a disruptor beam at the transmission, while the message is being copied and sent.


• So the message gets “mutated,” or scrambled by the disruptor beam:

• “Tie confetti Bomb’s the teacher is.”

• Or: • “Is a the confetti Tie Bomb teacher.


• Here are some other combos:

• Het rateehc’s eit si a ectitonf bbmo.• “tecitsiohentti’Tamabesecehrbfo.”• “The The The teacher’s teacher’s teacher’s tie

tie tie is is is a a a confetti confetti confetti bomb bomb bomb.

• Did this last one add MORE information?

• Did it add NEW information?

Mutated Building Instructions• ORIGINAL INFORMATION:• Using 100 3-16d schedule nails, face nail ceiling joists to

parallel rafters in a rectangular pattern.

• MUTANT VERSIONS:• Using 100 3-16d schedule ceiling joists joists, face nail to

nails parallel rafters in a rectangular pattern.• Nail rafter 100 ceiling face rectangular 3-16d pattern to

nails nails schedule, parallel using in a joists.• Unsig 010 36d-1 dscelueh anlis, cfae nila necliig jstsio ot

palreall frretas ni a gnartcauelr pntetra.

• Meet the Fruit Fly, a small fly that likes to eat fruit!

• Scientists like this little fly, because it’s easy to study.

They’ve been studying fruit flies for over 100 years.

They started in 1910!


• Fruit flies are easy to feed and keep alive.

• Their genetic code is also relatively simple, (it’s still millions of base pairs long) and scientists have been able to pinpoint most of what parts of the DNA code for what part of the fly.

What Are Mutations, and Do They Create MORE and NEW

Information?

• They know which part of the fly’s DNA codes for how to build legs, for example.

• They wanted to mutate the flies’ DNA to study how mutations would change the flies.

• They were successful.

• They made mutant fruit flies.


MUTANT FRUIT FLIES! AAHH!

• This is a normal fruit fly, or a "wildtype." Notice the shape and length of its wings. Normal Fruit Fly


• Notice the shortened wings of these flies. Flies with vestigial wings cannot fly: they have a defect in their "vestigial gene," on the second chromosome.

Normal Fruit Fly

Short Winged Fly

Harmful, Helpful, Neutral?


• Notice the curled wings of these flies. They have a defect in their "curly gene," which is on the second chromosome. Having curled wings is a dominant mutation, which means that only one copy of the gene has to be altered to produce the defect. In fact, if both copies are mutated, the flies do not survive.

Normal Fruit Fly

Curly Winged Fly



• Notice that these flies are yellower than normal flies. They have a defect in their "yellow gene," which is on the X chromosome. Since the yellow gene is needed for producing a fly's normal black pigment, yellow mutant flies cannot produce this pigment.

Normal Fruit Fly

Yellow Fruit Fly



• Notice that these flies have a dark, almost black, body. They carry a defect in their "ebony gene," on the third chromosome. Normally, the ebony gene is responsible for building up the tan-colored pigments in the normal fruit fly. If the ebony gene is defective, the black pigments accumulate all over the body.

Normal Fruit Fly

Black Fruit Fly



• Notice that these flies have orange eyes. They have a defect in their "white" gene, which normally produces the red pigments in the eye. In these flies, the white gene only works partially, producing fewer red pigments than it should.

Normal Fruit Fly

Orange Eyes Fruit Fly



• These flies have white eyes. Like the orange-eyed flies, they also have a defect in their "white" gene. But in these flies, the white gene is totally defective: it produces no red pigment at all.

Normal Fruit Fly

White Eyes Fruit Fly



• Notice that these flies have no eyes. They have a defect in their "eyes absent" gene, which normally instructs cells in the larvae to form an eye.

Normal Fruit Fly

Eyeless Fruit Fly



• Notice that these flies have abnormal, leg-like antennas on their foreheads. They have a defect in their "antennapedia" gene (Latin for "antenna-leg"), which normally instructs some body cells to become legs. In these flies, the antennapedia gene falsely instructs cells that would normally form antenna to become legs instead.

Normal Fruit Fly

Leg-headed Fruit Fly




• What do the fruit fly experiments tell us about mutations?

• Scientists were able to come up with thousands upon thousands of mutant flies.

• Was any new information added to the flies’ DNA? No.

• DNA information was switched around, turned off, scrambled, and duplicated.

• No NEW information was added. • In every example, the DNA mutations:

– Made wings that didn’t work.– Turned off a gene that made the fly a

certain color.– Made the fly blind, or with no eyes at all.– Removed the antenna and put non-

functioning legs in their place.

• Every mutation was either NEUTRAL or HARMFUL.


What’s the difference?

• Evolution (Sometimes called Macroevolution): Populations change because of copying errors in their DNA due to mutation. They pass their mutated genes on to their offspring, which become more and more complex. There has been a gain of new information through mutations – this is a problematic concept – remember the fruit flies?

• What is Natural Selection?(Sometimes called Microevolution): Organisms change because of their environment. The most “fit” survive, and pass on their genes to their offspring. The less fit die, taking their genes to the grave with them. As a result, the offspring populations have less genetic variety - there has been a loss of information - not a gain.

• The theory of Large-Scale Evolution relies upon mutations, a little bit at a time, to bit-by-bit change populations of organisms into populations of something else:

• Water, mud, a few chemicals to a self-reproducing molecule.

• Self-reproducing molecule to a single cell.• Cells to tiny multicellular organisms.• Tiny multicellular organisms to larger multicellular

organisms (like tiny worms).• Worms to fish.• Fish to reptiles.• Reptiles to birds.• Reptiles to dogs.

• Dogs to bears.

• Bears to elephants.

• Elephants to whales.

• Chimpanzees to humans.

Conclusion• Natural selection was Darwin’s idea.• Natural selection is an information-losing process.• Mutations don’t add any new information.• For life to go from simple to complex, you need MORE

information (DNA), and you need NEW information.

• “the problem of the origin of life is clearlybasically equivalent to the problem of the origin of biological information” [7, pp. 170-72].

Bernd-Olaf Kuppers (evolutionist)

evolution: natural selection, mutations, information

Education

history of darwin island

smallbeaked finches

small beak babies

bigbeaked finches

smallbeaked babies

smallbeak genes

population of finches

bigbeak genes