Changes Over Time Chapter 5 p. 144-173

Darwin’s Voyage Lesson 5-1

By the end of the lesson, I will be able to…  State

how Darwin explained variations among similar species.  Explain how scientists say that natural selection leads to evolution and the role of genes in evolution.  Describe how scientists think that new species form.

I. Darwin’s Observations A.

B. C. D.

In 1831, Charles Darwin and crew set off to learn about living things around the world. He saw many creatures on the Galapagos Islands that seemed unusual. Today, scientists have identified over 1.7 million species. A species is a group of similar organisms that can mate with each other and produce fertile offspring.

II. Similarities and Differences A.

B.

Many of the plants and animals on the Galapagos Islands were similar to organisms on the mainland. Some differences included birds being able to fly or not, iguanas having larger or smaller claws, the shapes of tortoises’ shells, and the shape and sizes of finches’ beaks.

III. Natural Selection A. B.

C.

Darwin said that evolution occurs by means of natural selection. Natural selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species. Darwin said there are 3 factors that affect natural selection: overproduction, competition, and variations.

III. Natural Selection D.

E.

F.

Many species produce too many offspring, so there aren’t enough resources for all of them to live (overproduction). Because of competition, many organisms survive because of “first come, first serve.” A variation is any difference between individuals of the same species.

III. Natural Selection G.

H.

Problems with natural selection: Organisms are able to change from one species to an other (evolution) because it makes life easier for them. Biblical solution: God allows organisms to be different – no two creatures are identical. However, organisms cannot change into a different species in order to survive.

IV. Adaptations An adaptation is a trait that helps an organism survive and reproduce. B. Problems with adaptations: It would take a long time for these changes to occur, so how could they survive in the meantime? How would their bodies be able to genetically make these changes if it wasn’t already in their genes? C. Biblical explanation: God created all creatures with dominant and recessive traits. Based on the traits they receive, they live in areas suitable for them. When they reproduce, the other trait becomes more sparse, leaving only the one phenotype. A.

V. Evolution A.

B.

Evolution is the thought that species gradually changed over many generations and became better adapted to the new conditions. A scientific theory is a well-tested concept that explains a wide range of observations.

V. Evolution C.

D.

Problems with evolution: Evolution cannot be tested or proved in any way. Scientists claim they haven’t been able to make observations for long enough, so evolution is really “scientific history.” Biblical Explanation: God clearly explains how all things came into existence, and he even wrote a book about it. Remember, God was the only one around at creation.

VI. The Role of Genes in Evolution A.

B.

Problems with evolution: Evolution was said to have happened because of mutations and natural selection, causing variations. Both of those cause a loss of information in a genome. So, where did all this new information come from? Biblical Explanation: God created all genes and traits at creation. Because of sin, mutations have occurred resulting in a loss of information for some genomes.

VII. Evolution in Action? A. B. C.

D. E.

Let’s read p. 154. Is that really evolution? Scientists say that a new species might form when a group of individuals remains separated from the rest of its species long enough to evolve different traits. Let’s read p. 155. Is that really a new species?

VIII. Continental Drift A.

B.

Geographic isolation may have occurred on a worldwide scale through continental drift. All the continents may have been joined together, and at some time split apart, separating many different organisms.

VIII. Continental Drift C.

D.

Problems with continental drift: The continents spread out slowly over millions of years, allowing organisms to evolve independently. Biblical Explanation: If the continents were joined together, the flood could have separated them. Animals and humans may have traveled by land bridges and slowly spread out over thousands of years. People could have taken seeds with them. Ultimately, we may never know exactly.

Assignment 

Write a 250+ word essay comparing what we as Christians believe about how living organisms came to be, and what scientists think. Be sure to include the phrases: natural selection, adaptations, evolution, and continental drift. Underline those phrases.

The Fossil Record Lesson 5-2 “No fossil, rock layer, or dating method can ever prove that evolution did, or did not, happen. The same is true for creation.”

By the end of the lesson, I will be able to…  Describe

how most fossils form.  Explain how a scientist determines a fossil’s age.  Describe the main events of the Geologic Time Scale.  Distinguish between gradualism and punctuated equilibria.

I. The Fossil Record A fossil is the preserved remains or traces of an organism that lived in the past. B. Very few fossils are of complete organisms. C. Most fossils form when organisms that die become buried in sediments. A.

I. The Fossil Record D.

E. F. G.

H.

Over time, sedimentary rock (rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together) forms over the organisms. Petrified fossils form when minerals replace all or part of an organism. A hollow space in sediment in the shape of an organism is a mold. A cast is when a mold is filled with minerals. Organisms can also be preserved in ice, tar, or amber (hardened tree sap).

I. The Fossil Record Problems with Fossils: Organisms died and were slowly covered with sediment over millions of years. J. Biblical Explanation: The flood washed sediment over the organisms and piled it on quickly. Also, the pressure of all the water cemented the sediment together. I.

II. Determining a Fossil’s Age A.

B.

C. D.

Scientists determine a fossil’s age in two ways: relative dating and absolute dating. Scientists use relative dating to determine which of two fossils is older. Relative dating shows that the lower sediment is, typically the older it is. Relative dating can only be used when the rock layers are in their original sequence.

II. Determining a Fossil’s Age Using absolute dating, scientists try to determine the actual age of fossils. F. The rocks that fossils are found near contain radioactive elements, unstable elements that decay. G. The half-life of a radioactive element is the time it takes for half of the atoms in a sample to decay. E.

II. Determining a Fossil’s Age I.

J.

Problem’s with Absolute Dating: Biologists assume that geologists have correctly identified the age of rocks, geologists assume that the chemists have correctly identified the half-life of different isotopes, and chemists assume that the physicists have correctly identified the details of radioactive decay. Scientists assume everything happened according to uniformitarianism and that nothing was made with age. Biblical Explanation: The Earth is 6-10,000 years old, so rocks can only be that old. All living creatures were created in the first week of the world’s existence. The flood was a catastrophic event that rapidly changed many things.

III. What do Fossils Reveal? A.

B. C.

The fossils that scientists have collected are called the fossil record. The fossil record is incomplete. Almost all of the species preserved as fossils are now extinct, meaning no members of that species are still alive.

III. What do Fossils Reveal? D.

E.

Problems with the Fossil Record: It’s incomplete, even though creatures have been around for millions of years. There are no “transition fossils”. Also, fossils should increase in complexity as you move up the layers of the Earth. Biblical Explanation: God made it all, most was destroyed in the flood, nothing has evolved.

IV. The Geologic Time Scale Using absolute dating, scientists have calculated the ages of many different fossils and rocks, determining that Earth is 4.6 billion years old. B. This time is split into smaller units called eras and periods. C. The longest period is Precambrian Time, lasting 4 billion years. D. Let’s look at p.162-163! A.

IV. The Geologic Time Scale E.

F.

Problems with the Geologic Time Scale: Many creatures did not live together at the same time. Bacteria, algae, and jellyfish were the first creatures. Life evolved over billions of years. Biblical Explanation: All things were created in 6 days, plants were the first living creatures, and the Earth is only 610,000 years old with nothing evolving.

V. How Fast does Evolution Occur? Gradualism is the theory that evolution occurs slowly but steadily. B. Punctuated equilibria is the theory that species evolve during short periods of rapid change. C. Biblical Explanation: God said, “Let there be,” and it was. Some organisms may have changed slightly over time. A.

Assignment 

Write a 250+ word essay comparing what we as Christians believe about fossils, and what scientists think. Be sure to include the phrases: fossil record, relative dating, absolute dating, half-life, geologic time scale. Underline those phrases.

Other Evidence for Evolution Lesson 5-3

By the end of the lesson, I will be able to…  State

evidence from modern-day organisms that scientists use to show evolutionary relationships among groups.  Explain what a branching tree diagram is.

I. Similarities in Body Structure An organism’s body structure is its basic body plan, such as how its bones are arranged. B. Homologous structures are similar structures that related species have inherited from common ancestors. C. Let’s look at p. 166! D. Biblical Explanation: The Creator of all things included similar characteristics among his creatures. A.

II. Similarities in Early Development Scientists look at the early development of many organisms to see if they have a common ancestor. B. Let’s look at p. 167! C. Biblical Explanation: Most living things start as a sperm and egg joined together. It’s amazing how different each creature is, even though they start so similarly. A.

III. Similarities in DNA Scientists compare the sequence of DNA in an organism with other organisms to see if they are related. B. Biblical Explanation: There are only 4 different nitrogen bases in DNA, so it is understandable that some DNA would be similar, but still different from others. A.

IV. Combining the Evidence Scientists combined evidence from fossils, body structures, early development, and DNA to determine evolutionary relationships. B. A branching tree is a diagram that shows how scientists think different groups of organisms are related. C. Biblical Explanation: Branching trees are missing many links, because they are not accurate. God made all things according to their “kind.” A.

Assignment 

Write a 250+ word essay on this topic:You have a friend who believes in evolution. What would you say to them about evolution? Remember to do this in a loving, gospel-centered way.