Who Came Up With Evolution?

Describe historical scientific developments that happened in evolutionary thought. For example, Lamarck and Darwin and Mendelian Genetics.


History of Evolution

Once scientists started noticing that the best organisms were surviving and the weak were dying, they called this natural selection. This part was clear to all scientists, as natural selection happened in all parts of their daily lives. What scientists did not agree upon, though, was how organisms got more advantageous characteristics, like long necks, specially adapted noses, or short beaks.

There is now a lot of evidence for the type of evolution that Darwin\"');" onmouseout="tooltip.hide();">Charles Darwin first proposed. It is not a fact that evolution happens this way, as the theory is always changing very slightly. Unlike natural selection, evolution is actually a fairly complicated theory that takes some time to truly understand. However, evolution takes into account all of the current evidence that scientists have brought to light.

Evolution: The Ride

Evolution basically means that groups of organisms change over time. These groups, or populations, get more and more advantageous characteristics for their environment over the course of many generations. Short-trunked elephants were not suddenly taken over by one mysterious long-trunked elephant. What most likely happened with elephants is that the elephants in each generation with the longest necks were the ones to survive.

Evolution does not happen to individual organisms. Individual organisms can change, but unless that change gives them an advantage and they can pass it on to their offspring, it will not matter. If the male elephant with a longer neck is unattractive and smelly, then it’s possible he won’t be able to find a lady elephant and will never pass on his longer neck to any offspring. How sad!

Evolution is not just a series of accidents. Unless a change has some advantage, the organism will not survive as well and die. It is also not a series of events to get to some end animal. Evolution didn’t happen to elephants because elephants were destined to have long trunks.

Evolution happens for a reason: The changes in the population help the organisms survive better. Since there can be millions of different possible changes, there is no “correct” change that has to happen. Nobody can predict how evolution will change bacteria, elephants or even humans over the next million years.

Evolution is not just a theory about humans, it’s about all living things. Evolution is also not a system of beliefs! Evolution just happens to be the best explanation for what scientists can observe about the world. Therefore, evolution says nothing about the presence or absence of God, or about what you should or should not believe.

There are many misconceptions about evolution. Scientists do not think that humans evolved from monkeys; rather, humans and monkeys are thought to have a common ancestor some many millions of years ago. This ancestor was not necessarily like today’s monkeys and also not exactly like a human. But because evolution means that organisms are constantly improving themselves over time, this ancestor of ours does not exist any more because some of their offspring evolved into monkeys and some into humans.

Another misconception about evolution is that humans and dinosaurs lived at the same time. Well, it is true that ancient ancestors of humans, about the size and shape of a large mouse, lived at the same time as dinosaurs. However, it took millions of years after dinosaurs went extinct for most of the mammals that are around today to evolve, including humans!

Questions
Remember
1. Complete this phrase in your own words: Evolution means that _________________________________________________________________________
2. Did humans evolve from monkeys? Explain!
3. Is evolution happening right now?
Put it together
4. Is there such a thing as scientific fact? Why or why not?
5. Infer what would have happened if the common ancestor between monkeys and humans had never been able to reach the ground from the trees it lived in. Come up with at least two points to support your hypothesis.
Think about it
6. Think about the small mammal that was described at the end of the reading. After the dinosaurs went extinct, how do you think this population of mouse-like mammals started to evolve? Come up with three different populations of organisms that you feel must have evolved from this one mouse-like population. Describe each one in one paragraph that explains why they evolved the way that they did and make a quick sketch of each one.
Review
7. How was Earth formed?

9. Why doesn't it matter what scientists think about natural selection?

Lamarck vs. Darwin

Early mammal evolution. All sizes are relative to each other!

Lamarck\"');" onmouseout="tooltip.hide();">Jean-Baptiste Lamarck (1744-1829) and Darwin\"');" onmouseout="tooltip.hide();">Charles Darwin (1809-1882) both thought and had ideas about how life on earth got to be the way it is now. They had some similar and some very different ideas.

How They Agreed

Unlike most other people at that time, Darwin and Lamarck both thought that life had changed gradually over time and was still changing, that living things change to be better suited and adapted to their environments, and that all organisms are related. Darwin and Lamarck also agreed that life evolved from fewer, simpler organisms to many, more complex organisms.

What Lamarck Thought

Lamarck is best known for his Theory of Inheritance of Acquired Characteristics, first presented in 1801 (Darwin’s first book dealing with natural selection was published in 1859): If an organism changes during life in order to adapt to its environment, those changes are passed on to its offspring. He said that change is made by what the organisms want or need. For example, Lamarck thought that elephants all used to have short trunks. When there was no food or water that they could reach with their short trunks, they stretched their trunks to reach the water and branches, and their offspring inherited long trunks. Lamarck also said that body parts that are not being used, such as the human appendix and little toes are gradually disappearing. Eventually, people will be born without these parts. Lamarck also thought that evolution happens according to a predetermined plan and that the results have already been decided.

What Darwin Thought

An elephant. His name might be Bob.

Darwin thought that the desires of animals have nothing to do with how they evolve, and that changes in an organism during its life do not affect the evolution of the species. He said that organisms, even of the same species, are all different and that those which happen to have variations that help them to survive in their environments survive and have more offspring. The offspring are born with their parents’ helpful traits, and as they reproduce, individuals with that trait make up more of the population. Other individuals, that are not so well adapted, die off. Most elephants used to have short trunks, but some had longer trunks. When there was no food or water that they could reach with their short trunks, the ones with short trunks died off, and the ones with long trunks survived and reproduced. Eventually, all of the elephants had long trunks. Darwin also thought that evolution does not happen according to any sort of plan.

Why We Agree With Darwin

Darwin’s theory has been supported by a lot of evidence. Lamarck’s Theory of Inheritance of Acquired Characteristics has been disproved. This was done in two major ways. The first is by experiment. We have seen through many real examples and observations that changes that occur in an animal during life are not passed on to the animal’s offspring. If a dog’s ears are cropped short, its puppies are still born with long ears. If someone exercises every day, runs marathons, eats well, and is generally very healthy, the fitness is not passed on and the person’s children still have to work just as hard to get that fit and healthy. These and other examples show that Lamarck’s theory does not explain how life formed and became the way it is.

The other way that Lamarck’s theory has been proven wrong is the study of genetics. Darwin knew that traits are passed on, but he never understood how they are passed on. During the time when Darwin’s first book first came out, Gregor Mendel, who discovered genetics, was just starting his experiments. However, now we know a lot more about genetics, and we know that the only way for traits to be passed on is through genes, and that genes can not be affected by the outside world very well. The only thing that can be affected is which gene sets there are in a population, and this is determined by which individuals die and which ones live. This is the other way that we have learned that the fruits of an animal’s efforts can not be inherited by its offspring.

Respond

  1. What did Darwin think?
  2. What did Lamarck think?
  3. Who was more correct? Why?
  4. If evidence came along suggesting that evolution was wrong, what would scientists do?
Nature’s Pharmacy

This lab activity will offer a chance for you to get to know the many naturally found antibacterial

substances… sitting right on your kitchen shelves.

  1. Form groups of 3 – 4. Assign an equipment manager, scribe and leader. If there’s a fourth person, then they should be the official reader.
  2. You will be preparing an agar plate with four spices from the spice options offered by your teacher. Choose the four that you want to test.
  3. What is a zone of inhibition? Why is it important to the results of this experiment?
  4. Put on your safety equipment. Divide the agar plate in four quadrants (on the bottom) with the marker. Label the top of the agar plate with the spices that you have chosen.
  5. Inoculate your plate with the liquid bacteria, according to the teacher’s instructions.
  6. Apply the chosen spices to the quadrants on the agar plate. Close up the plate so that the top and bottom line up. Leave them in a safe place, at room temperature for three days.
  7. Write down your hypothesis about what you think you will see in three days, and why.
  8. At the end of three days, look at your results. Draw your plate as accurately as possible.
  9. Measure any zones of inhibition around the spices and record the data. Share the data with the entire class on the board.
  10. Do the sizes of the zones vary from each other, or other groups?
  11. Do your results match your hypothesis? Why or why not?
  12. Prepare a one-minute report for the entire class. Include which spices you used, which you think are the best and which you think are the worst at resisting this particular bacteria.
Graphing Opinions
  1. Using the class’ responses from the 15 true/false questions at the beginning of this chapter, create a tally of how many people got the right answer for each question.
  2. Calculate the percentage of students who were correct for each question and place that number next to the tally.
  3. Create a line or bar graph that represents the percentages that you just calculated.
  4. Which question(s) were most correctly responded? Why?
  5. Which question(s) were least correctly responded? Why?
Evolution: What Do You Think?
  1. Ask family and friends for at least three questions that they have about evolution. For each question, write down exactly what question they asked.
  2. In addition to the three questions you got from friends and family, look up the answers to two more questions that you would like to know the answers to.
  3. Using each of the answers you got in #2, explain in your own words what you could tell other people in order to fully answer the question.
Beetles: Part 1

This is an introduction to evolution and an activity that you can do with other people.
http://2.bp.blogspot.com/-N1kAsJPMLs8/TeUeOX1vI5I/AAAAAAAAAuo/CsFFtelPNcI/s1600/Step+3+illus.jpg

  1. You will take a single piece of paper and fold it in half four times and then cut along all of the folds. You should now have sixteen pieces of paper.
  2. On each of those pieces of paper, you will draw a beetle. Each beetle should have the following features:
    1. A body
    2. Antennae, either short or long
    3. Six legs, either short or long
    4. Eyes, either small or big
    5. Beak (mouth), either small or big


http://img.oncoloring.com/beetle_497ad4053f62c-p.gifTry your best to make each beetle different; this means that if one beetle has short antennae, short legs, small eyes and a small beak, then your next beetle might have short antennae, short legs, small eyes and a big beak.

  1. The next step is where you will need another person. Ask the person to come up with an imaginary environment for your beetles and ask them the following questions:
    1. Do the beetles need to feel things that are very tall?
    2. Do the beetles need to be able to run very quickly?
    3. Do the beetles need to see things from far away?
    4. Do the beetles need to eat things that are very big?
  2. Given this environment from #3, decide which four of your sixteen beetles are best suited for their environment. Indicate on the individual beetles which four those are.
  3. Write a paragraph of at least 5 sentences that explains why those four beetles are best suited for the environment.
  4. Turn in your beetles and the answers to the above questions. Keep in mind that you will use your beetles for the next homework assignment!

 

Hide a Butterfly

From Jennifer Weiss

  1. Get three butterflies and colored pencils.
  2. Your objective is to color the butterflies in such a way that they will not be eaten by birds (played by other students or faculty members). Observe places in the room that might make an excellent hiding place. Play close attention to borders, corners, places where there are many colors all in the same location, and rarely-used spaces. Keep in mind that your butterfly must be visible, even if it’s hard to see.
  3. Color your butterflies and tape it in the appropriate place.
  4. Before the “bird” finds butterflies, respond:
    1. What were the places you found?
    2. Why did you choose these places?
    3. What sorts of adaptations do real butterflies make in order to not be seen?
  5. Once the “bird” finds butterflies, respond:
    1. How many of your butterflies did the bird find?
    2. Why did they find the ones they found, and why did they not find the ones they didn’t find?
    3. What did you learn about hiding butterflies in the room?