Did we come from monkeys?

Clarifying Some Common Misconceptions about Evolution

So what is evolution anyway?Evolution in its simplest definition is just a change in a species over a period of time. These changes are introduced into a population through random mutations. Evolution is an explanation for the vast diversity of different organisms found in the world.

So what is evolution anyway?Evolution in its simplest definition is just a change in a species over a period of time. These changes are introduced into a population through random mutations. Evolution is an explanation for the vast diversity of different organisms found in the world.

But it’s just a theory!A theory is a highly reliable explanation of a natural phenomenon that is based on many experiments. A theory is never proven right; new evidence will either continue to support it or disprove it. Darwin’s theory of evolution has withstood the test of time and continues to be supported even when new technology uncovers new evidence.

Lamarck Jean Baptiste Lamarck (1774-1829) was a French scientist who

proposed the theory of:

Theory of Acquired Characteristics

He thought an individual could change its physical characteristics in response to the environment and then be able to pass those traits along to any offspring. He also thought that if a structure or organ was not being used, it would shrink or even disappear.

Lamarck’s famous example was that if a giraffe needed a longer neck to reach leaves on the top of trees, it could stretch its neck as needed. He then thought the longer neck would be passed on to the giraffe’s offspring.

Lamarck was wrong!

So the child of a body builder isn’t going to be born with automatically large muscles.

That’s my boy!Dada?

Maybe it’s a good thing we can’t pass along acquired traits…..

DarwinCharles Darwin (1809-1882) was a naturalist who traveled the world and ended up at the Galapagos Islands. He observed the vast variety of living things on those islands and developed his theory of evolution by natural selection. He also came up with the idea that all living things evolved from a common ancestor.

Serious Darwin

Party Darwin

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Conservation of DNA

Some evidence that supports a common ancestry among living things includes our DNA. We know that the DNA of all living organisms from bacteria to humans is made up of the same four bases: adenine, thymine, cytosine and guanine.

This chart shows the conservation of DNA between some species. Conservation of DNA means that this is the amount of DNA base sequences different species have in common.

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So….did we come from monkeys or not?No, evolution does not say we evolved from monkeys, gorillas or chimpanzees. Evolution does say we share a common ancestor somewhere along the way, which makes us related. Chimpanzees are actually our closest relative. Scientists believe our common ancestor existed about 5-8 million years ago. From there, humans and apes diverged into two separate lineages.

If we compare our evolutionary history to a family tree,it looks like this:

Common Ancestor

Monkey Orangutan Gorilla Chimpanzee

Human

Natural Selection

Natural selection is a mechanism for how evolution occurs. An individual that has a beneficial characteristic, called an adaptation, that allows it to survive in a particular environment is more likely to live long enough to reproduce and pass on its genes for that adaptation. Over time, this can change the genetic variation of a population.

● Physical adaptations are body structures that allow an animal to find and consume food, defend itself, and to reproduce its species.

● Physical adaptations help an animal survive in its environment.

Hey! I’m a walking

stick. I look just like a

stick you’d find on the

ground.

© A. Weinberg

Physical adaptation

Camouflage (use of color in a surrounding)

The chameleon can change its color to match its surroundings. Can you do that?

Mimicry (looking or sounding like another living organism)

The Viceroy butterfly uses mimicry to look like the Monarch butterfly. Can you tell them apart?

Poisonous

Not poisonous

Physical adaptation

I’m the Monarch!

I’m the Viceroy!

Chemical defenses (like venom, ink, sprays)

Physical adaptation

Body coverings & parts (claws, beaks, feet, armor plates, skulls, teeth)

Physical adaptations

The elephant’s trunk is a physical adaptation that helps it to clean itself, eat, drink, and to pick things up.

Each organism has unique methods of

adapting to its environment by means

of different actions.

Behavioral Adaptations are animals’ actions.

Behavioral Adaptations allow animals to respond

to life needs.

“Survival of the Fittest”

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The population, not the individual, evolves.

Evolution depends on random, pre-existing traits in an individual that end of making it better adapted for its environment. Just because an organism needs a certain characteristic to survive does NOT mean it will spontaneously be able to develop it.

Artificial Selection - Selection conducted under human direction. The intentional selection of individual with specific traits to get the desired results in the offspring.

How long does evolution take?Evolution does not occur instantly. It is a process that takes many generations for a change to start to show up in a population. An organism like bacteria can reproduce quickly, so twenty generations can be a short amount of time. An organism like an elephant reproduces slowly making twenty generations span a much longer time period.