Transcript Prentice Hall Biology
Section 17-1
Interest Grabber Half of a Half of a Half . . .
Some forms of chemical elements are unstable —that is, they break down into other substances. Like the decay of leftovers in your refrigerator, this breakdown takes place over time. Unlike those leftovers, however, the breakdown of unstable forms of an element progresses in a very orderly way —by decaying into halves.
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Section 17-1
Interest Grabber
continued
1. Using your ruler, draw a line 24 cm in length on a sheet of paper. Make a mark at the halfway point (12 cm).
2. Then, divide this 12-cm segment in half, making a mark at 6 cm. Continue in this way, dividing each progressively smaller segment in half (ignoring all of the other segments) until it becomes too small to accurately measure.
3. Now count each progressively smaller half-segment. How many segments did you count?
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Section 17-1
Section Outline 17 –1 The Fossil Record
A. Fossils and Ancient Life B. How Fossils Form C. Interpreting Fossil Evidence 1. Relative Dating 2. Radioactive Dating D. Geologic Time Scale 1. Eras 2. Periods Go to Section:
Compare/Contrast Table
Section 17-1
Comparing Relative and Absolute Dating of Fossils
Relative Dating Absolute Dating
Can determine Is performed by Age of fossil with respect to another rock or fossil (that is, older or younger) Comparing depth of a fossil’s source stratum to the position of a reference fossil or rock Age of a fossil in years Determining the relative amounts of a radioactive isotope and nonradioactive isotope in a specimen Drawbacks Imprecision and limitations of age data Difficulty of radioassay laboratory methods Go to Section:
Section 17-1
Figure 17-2 Formation of a Fossil
Water carries small rock particles to lakes and seas.
Dead organisms are buried by layers of sediment, which forms new rock.
The preserved remains may later be discovered and studied.
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Section 17-1
Figure 17-5 Geologic Time Scale
Era Period
Quaternary Tertiary Cretaceous Jurassic Triassic
Time
(millions of years ago) 1.8
–present 65 –1.8
145 –65 208 –145 245 –208
Era Period
Permian Carboniferous Devonian Silurian Ordovician Cambrian
Time
(millions of years ago) 290 – 245 360 –290 410 –360 440 –410 505 –440 544 –505
Era Period
Vendian
Time
(millions of years ago) 650 –544 Go to Section:
Section 17-1
Figure 17-5 Geologic Time Scale
Era Period
Quaternary Tertiary Cretaceous Jurassic Triassic
Time
(millions of years ago) 1.8
–present 65 –1.8
145 –65 208 –145 245 –208
Era Period
Permian Carboniferous Devonian Silurian Ordovician Cambrian
Time
(millions of years ago) 290 – 245 360 –290 410 –360 440 –410 505 –440 544 –505
Era Period
Vendian
Time
(millions of years ago) 650 –544 Go to Section:
Section 17-1
Figure 17-5 Geologic Time Scale
Era Period
Quaternary Tertiary Cretaceous Jurassic Triassic
Time
(millions of years ago) 1.8
–present 65 –1.8
145 –65 208 –145 245 –208
Era Period
Permian Carboniferous Devonian Silurian Ordovician Cambrian
Time
(millions of years ago) 290 – 245 360 –290 410 –360 440 –410 505 –440 544 –505
Era Period
Vendian
Time
(millions of years ago) 650 –544 Go to Section:
Section 17-2
Interest Grabber Mystery Detective
Earth is billions of years old. There were not any witnesses to those early years. How, then, can scientists determine the conditions on Earth long before there were any scientists?
Think about how you draw conclusions about occurrences that you did not witness. If you saw the charred remains of a house, for example, you could infer that it burned down.
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Section 17-2
Interest Grabber
continued
1. On a sheet of paper, list things that you can observe around you that lead you to infer about events you did not see. For example, what do skid marks in the roadway tell you? 2. Now, think about and list the evidence all around you that scientists might analyze when trying to piece together a history of Earth. How would finding the fossil of a sea animal in the middle of a desert tell a scientist something about the past?
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Section 17-2
Section Outline 17 –2 Earth’s Early History
A. Formation of Earth B. The First Organic Molecules C. How Did Life Begin?
1. Formation of Microspheres 2. Evolution of RNA and DNA D. Free Oxygen E. Origin of Eukaryotic Cells F. Sexual Reproduction and Multicellularity Go to Section:
Concept Map
Section 17-2
Evolution of Life Early Earth was hot; atmosphere contained poisonous gases.
Earth cooled and oceans condensed.
Simple organic molecules may have formed in the oceans..
Small sequences of RNA may have formed and replicated.
First prokaryotes may have formed when RNA or DNA was enclosed in microspheres.
Later prokaryotes were photosynthetic and produced oxygen.
An oxygenated atmosphere capped by the ozone layer protected Earth.
First eukaryotes may have been communities of prokaryotes.
Multicellular eukaryotes evolved.
Sexual reproduction increased genetic variability, hastening evolution.
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Section 17-2
Figure 17-8 Miller-Urey Experiment
Mixture of gases simulating atmospheres of early Earth Spark simulating lightning storms Condensation chamber Water vapor Cold water cools chamber, causing droplets to form Liquid containing amino acids and other organic compounds Go to Section:
Figure 17-12 Endosymbiotic Theory
Section 17-2
Chloroplast Aerobic bacteria
Ancient Prokaryotes
Nuclear envelope evolving Photosynthetic bacteria Mitochondrion
Ancient Anaerobic Prokaryote
Plants and plantlike protists
Primitive Aerobic Eukaryote Primitive Photosynthetic Eukaryote
Animals, fungi, and non-plantlike protists Go to Section:
Section 17-3
Interest Grabber Team, Team, Team!
The first living things were unicellular. You, however, are multicellular. Is there an advantage to being multicellular?
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Section 17-3
Interest Grabber
continued
1. Make a list of at least six different organs in your body, and next to each, write the main function of that organ. 2. Now, examine your list. Do any main functions overlap? Do two or more organs do exactly the same thing?
3. Use your list to jog your memory, and write down the functions that must be performed by a unicellular organism. For example, you may have written that your nerves help you sense your environment. Doesn’t a cell need to sense its environment, too?
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Section Outline
Section 17-3
17 –3 Evolution of Multicellular Life
A. Precambrian Time B. Paleozoic Era 1. Cambrian Period 2. Ordovician and Silurian Periods 3. Devonian Period 4. Carboniferous and Permian Periods C. Mesozoic Era 1. Triassic Period 2. Jurassic Period 3. Cretaceous Period D. Cenozoic Era 1. Tertiary Period 2. Quaternary Period Go to Section:
Geologic Time Scale with Key Events
Section 17-3 Era Cenozoic Mesozoic Paleozoic Precambrian Time Period
Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian
Time
(millions of years ago) 1.8
–present 65 –1.8
145 –65 208 –145 245 –208 290 –245 363 –290 410 –363 440 –410 505 –440 544 –505 650 –544
Key Events
Glaciations; mammals increased; humans Mammals diversified; grasses Aquatic reptiles diversified; flowering plants; mass extinction Dinosaurs diversified; birds Dinosaurs; small mammals; cone-bearing plants Reptiles diversified; seed plants; mass extinction Reptiles; winged insects diversified; coal swamps Fishes diversified; land vertebrates (primitive amphibians) Land plants; land animals (arthropods) Aquatic arthropods; mollusks; vertebrates (jawless fishes) Marine invertebrates diversified; most animal phyla evolved Anaerobic, then photosynthetic prokaryotes; eukaryotes, then multicellular life Go to Section:
Section 17-4
Interest Grabber Birds of a Feather
Darwin was surprised by the number of similar but not identical species that he observed. Look around you –can you make the same observation?
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Section 17-4
Interest Grabber
continued
1. Choose a type of animal in your area that is represented by several species, such as songbirds.
2.
Make a list of examples of this type of animal. If you don’t know the name of an animal, write a brief description instead.
3. Count the number of different examples you have identified. Then, write down characteristics found in all of the examples. Do the examples in your list seem to be more closely related to each other or to other types of animals? Go to Section:
Section 17-4
Section Outline 17 –4 Patterns of Evolution
A. Extinction B. Adaptive Radiation C. Convergent Evolution D. Coevolution E. Punctuated Equilibrium F. Developmental Genes and Body Plans Go to Section:
Flowchart
Section 17-4 Species
that are form Inter relationshiops can undergo Coevolution Unrelated Related in Similar environments can undergo Convergent evolution under Intense environmental pressure can undergo under in Small populations can undergo Extinction Punctuated equilibrium in Different environments can undergo Adaptive radiation Go to Section:
Videos
Click a hyperlink to choose a video.
Geologic Time
Evolution of Cells
Video 1
Geologic Time Click the image to play the video segment.
Video 2
Evolution of Cells Click the image to play the video segment.
Go Online
Career links on fossil preparators Interactive test For links on the fossil record, go to www.SciLinks.org
Web Code as follows: cbn-5171.
and enter the For links on eukaryotic cells, go to www.SciLinks.org
Code as follows: cbn-5172.
and enter the Web For links on extinction, go to www.SciLinks.org
as follows: cbn-5174.
and enter the Web Code
Interest Grabber Answers
1. Using your ruler, draw a line 24 cm in length on a sheet of paper. Make a mark at the halfway point (12 cm).
2. Then, divide this 12-cm segment in half, making a mark at 6 cm. Continue in this way, dividing each progressively smaller segment in half (ignoring all of the other segments) until it becomes too small to accurately measure.
3. Now count each progressively smaller half-segment. How many segments did you count?
Student answers will vary. Have students retain their paper and refer to it when the half-life of radioactive isotopes is discussed.
Interest Grabber Answers
1. On a sheet of paper, list things that you can observe around you that lead you to infer about events you did not see. For example, what do skid marks in the roadway tell you? Students’ lists will vary. Remind those having trouble that they can list everyday events, such as finding a half-eaten pizza in their refrigerator. Skid marks tell you that a car stopped or started very quickly.
2. Now, think about and list the evidence all around you that scientists might analyze when trying to piece together a history of Earth. How would finding the fossil of a sea animal in the middle of a desert tell a scientist something about the past?
Students may say that a trained observer can see the remains of a past event, and some may know that geology provides many clues to Earth’s past. For example, finding a fossil of a fish in a desert would indicate that the area had once been under water.
Interest Grabber Answers
1. Make a list of at least six different organs in your body, and next to each, write the main function of that organ. Students’ answers may include lung, skin, heart, stomach, kidney, and so on.
2. Now, examine your list. Do any main functions overlap? Do two or more organs do exactly the same thing?
To get students started, suggest an organ/function pair such as stomach/digest food or kidneys/remove wastes from blood.
3. Use your list to jog your memory, and write down the functions that must be performed by a unicellular organism. For example, you may have written that your nerves help you sense your environment. Doesn’t a cell need to sense its environment, too?
Students should be aware that unicellular organisms use food, exchange gases, get rid of wastes, make new cell components, and for some cells, actively move.
Interest Grabber Answers
1. Choose a type of animal in your area that is represented by several species, such as songbirds.
2.
Make a list of examples of this type of animal. If you don’t know the name of an animal, write a brief description instead.
3. Count the number of different examples you have identified. Then, write down characteristics found in all of the examples. Do the examples in your list seem to be more closely related to each other or to other types of animals? Possible answers may include the following: Songbirds are small, perching birds that eat seeds or insects. They seem more closely related to each other than to other birds (and to other animals in general).
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