1 The origin of life (pp )

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ST chapter only Checkup Chapter 10 1 The origin of life (pp. 300 305) 1. Earth took millions of years to form.

6 billion years ago c) How did the Moon form? From a large celestial body colliding with Earth 2. Look at the photos at right.

1 ST chapter only Checkup Chapter 10 1 The origin of life (pp ) 1. Earth took millions of years to form. a) Where did the matter that formed our planet come from? From a cloud of gas and dust that created our solar system. b) How long ago did Earth form? About 4.6 billion years ago c) How did the Moon form? From a large celestial body colliding with Earth 2. Look at the photos at right. a) What favourable condition for the emergence of life is illustrated in photo 1? The presence of liquid water b) What favourable condition for the emergence of life is illustrated in photo 2? The presence of an energy source B 89 CHECKUP OF CHAPTER 10

2 c) What are the other two favourable conditions essential for the emergence of life and that are not illustrated in these photos? The presence of essential chemical elements necessary for life and a very long period of time 3. a) Complex organic molecules are mainly made up of which chemical elements? Carbon (C), oxygen (O), hydrogen (H) and nitrogen (N) b) Where do scientists believe these organic molecules were when they first organized into living cells? In liquid water c) Why did it take so long for the first cells to form? The more time passed, the greater the number of molecular bonds formed and the greater the probability of producing living cells. d) When did life first appear on Earth? 3.5 to 3.8 billion years ago e) What were the first forms of life to appear on Earth? Cyanobacteria 2 The history of life on Earth (pp ) 4. A great number of species have appeared since the beginning of life on Earth. a) Name the very slow process that brings about modifications in living beings. Evolution b) Name the natural process that gradually results in the reproduction of living organisms better adapted to their environment. Natural selection CHECKUP OF CHAPTER B

3 5. Which of the four geological eras is described in each of the following examples? a) era in which we live at present Cenozoic era b) era when many dinosaur species lived, as well as when they all became extinct Mesozoic era c) the longest geological era of the four Precambrian era d) era during which most species of mammals appeared e) era that ended with the biggest extinction event ever Cenozoic era Paleozoic era 6. Here are a few important events in the history of life: Appearance of amphibians and insects Appearance of our species Appearance of dinosaurs First evidence of life Appearance of vertebrates Appearance of soft-bodied invertebrates Extinction of about 90 percent of all marine species Extinction of dinosaurs Appearance of fish In the table on the next page: a) In the first column, write the events in chronological order. b) In the second column, write the geological era in which each event occurred. c) In the third column, write the geological period in which each event occurred. Do not indicate anything for events that occurred during the Precambrian era B 91 CHECKUP OF CHAPTER 10

EVENT ERA PERIOD First evidence of life Precambrian Appearance of soft-bodied invertebrates Precambrian Appearance of vertebrates Paleozoic Ordovician Appearance of fish Paleozoic Ordovician

4 EVENT ERA PERIOD First evidence of life Precambrian Appearance of soft-bodied invertebrates Precambrian Appearance of vertebrates Paleozoic Ordovician Appearance of fish Paleozoic Ordovician Appearance of amphibians and insects Paleozoic Devonian Extinction of about 90 percent of all marine species Paleozoic Permian Appearance of dinosaurs Mesozoic Triassic Extinction of dinosaurs Mesozoic Cretaceous Appearance of our species Cenozoic Quaternary 7. Below is a photo of the fossil of a species of fish that lived 380 million years ago in an area that is now the Gaspé Peninsula. In which era and period on the geological time scale did this fish live? In the Devonian period of the Paleozoic era CHECKUP OF CHAPTER B

5 8. Jurassic Park, the first film of a science fiction trilogy about dinosaurs, was released in theatres in Why was this an appropriate title for a film about dinosaurs? The number of species of dinosaurs multiplied during this period. 9. Apes and humans are animals from the order of Primates. a) Which ape is our closest cousin? Chimpanzee b) What characteristic do paleontologists rely on to distinguish humans and apes in evolution? To be considered human, the species must rely on bipedalism more than 50% of the time to move around. 10. The human lineage contains many species, all of which are extinct except our own. a) What are the three main genera of the human lineage? Australopithecus Paranthropus Homo b) What is the scientific name of our species? Homo sapiens c) What are the names of the two human species that once lived at the same time as us? Homo neanderthalensis Homo floresiensis 11. Our species has undergone many adaptations since its appearance. Explain one advantage for each of the following adaptations. a) bipedalism This freed up our hands for other uses, such as making tools and clothes B 93 CHECKUP OF CHAPTER 10

6 b) our brain, which is highly developed compared to that of other species We have superior mental capabilities compared to other animals. For example, we are inventive and can communicate using complex languages. c) our hair, which is finer than that of other mammals This enables us to keep cool in hot environments. d) our many sweat glands This enables us to keep cool in hot environments. 12. Explain why it is difficult for scientists to establish exactly how the human species evolved. There are relatively few human fossils. 3 Fossils (pp ) 13. In what type of rock are fossils most often discovered? In sedimentary rocks 14. Look at the photos below. CHECKUP OF CHAPTER B

7 a) Identify the type of fossil illustrated in each one. b) Briefly describe how each fossil was formed. Write your answers in the table below. FOSSIL TYPE FORMATION Trace fossil A trace left by an organism that lived a long time ago and that has fossilized. 1 Petrified fossil The remains of an organism, primarily bones, that hardened into rock. 2 Cast fossil The impression of an organism moulded in rock a) What type of fossil is not included in the photos in question 14? Body fossil b) Provide two examples of this type of fossil and how each was formed. An insect trapped in resin that turned into amber An animal trapped in ice B 95 CHECKUP OF CHAPTER 10

8 16. True or false? If false, explain your answer. TRUE FALSE a) Geologists specialize in the study and research of fossils. Geologists specialize in rocks while paleontologists specialize in fossils. b) A tree trunk can become fossilized. c) Many fossils are found in Québec, mainly in magmatic rock. Fossils are found mostly in sedimentary rocks. d) All the organisms that die will one day become fossils. When an organism dies, it usually decomposes. CHECKUP OF CHAPTER B

9 TRUE FALSE e) On a fossil, parts of an organism can be petrified and others moulded. f) Relative dating is more accurate than absolute dating. These two methods are different. Depending on the case, either one can be more accurate. g) A fossil that formed 25 million years ago contains more carbon-14 than one that formed 60 million years ago. In both cases, the fossils are too old to measure the amount of carbon-14 they contain. 17. In your own words, explain the Laws of Continuity and Superposition of stratigraphic layers. According to the Law of Continuity, all the fossils contained in the same stratigraphic layer were formed in the same time period. According to the Law of Superposition, the deeper the stratigraphic layer, the older it is B 97 CHECKUP OF CHAPTER 10

18. What type of dating is referred to in each of the following examples? a) One tree is older than another because it is bigger. b) A tree is 12 years old because it has 12 growth rings.

10 18. What type of dating is referred to in each of the following examples? a) One tree is older than another because it is bigger. b) A tree is 12 years old because it has 12 growth rings. Relative dating Absolute dating 19. a) On what properties of certain elements is carbon-14 dating based? Radioactivity b) How can the age of a fossil be determined using this method of absolute dating? By measuring the proportion of carbon-14 it contains 20. Carefully study the illustration at right. It includes three stratigraphic layers and the fossils they contain. a) What colour is the oldest stratigraphic layer? Explain your answer using the principle on which it is based. According to the Law of Superposition, layer 3 is the oldest because it is the deepest. b) What species appeared first? Explain your answer. Species B appeared first because fossils of this species are found in a deeper stratigraphic layer than that of species A. CHECKUP OF CHAPTER B

11 c) What species disappeared last? Explain your answer. Species B disappeared last because fossils of this species are found in a shallower stratigraphic layer than that of species A. d) Did species B exist at the same time as species A? Explain your answer. Yes. Species B existed at the same time as species A because fossils of both species are found in the same stratigraphic layer. e) What type of dating helps determine the age of a stratigraphic layer according to its location with regard to other layers? Relative dating f) If fossils of species A and species B are estimated to be more than years old, what radioactive element could be used to determine the age of the two fossils? Uranium B 99 CHECKUP OF CHAPTER 10

1 The origin of life (pp )

1 The origin of life (pp ) ST chapter only Checkup Chapter 10 1 The origin of life (pp. 300 305) 1. Earth took millions of years to form. a) Where did the matter that formed our planet come from? b) How long ago did Earth form?