10.7 4.2.8 - exercises

Exercises

Question 1

1. In each of the following cases, write down the LETTER of the most correct alternative:
   1. Which of the following fossils have been found in Namibia ?
      1. Mammal-like reptiles
      2. Glossopteris leaves
      3. Soft-bodied animals
      4. Early mammals
   2. What was the importance of stromatolites ?
      1. They released oxygen into the air.
      2. They absorbed oxygen and prevented animals being poisoned.
      3. They are the closest ancestors of modern plants.
      4. They were algae trapped in sediment.
   3. A problem in determining the accuracy of radiometric dating is that …
      1. scientists are not sure that radioactive decay actually occurs.
      2. the decay rate of the minerals can change without warning.
      3. the rocks that contain the fossils can’t be dated.
      4. only organic samples can be dated radiometrically.
   4. Continental drift accounts for the fact that people have found …
      1. fern-like fossils in Africa.
      2. the fossils of subtropical plants in Antarctica.
      3. tectonic plates under the continents.
      4. trilobite fossils in almost all continents.
   5. Which statement below DOES NOT apply to the Paleozoic era?
      1. Trilobites and algae were the dominant life forms.
      2. Coal swamps were formed in many areas.
      3. It started with the Cambrian explosion.
      4. Birds developed during this era. [10]

Question 2

Match the terms in the first column with the phrases / descriptions in the second column. Write down only the correct LETTER next to the question number:[5]

Question 3

Give the correct biological TERM for each of the following. Write down only the question number and the answer.

1. The era during which ferns and cycads were the dominant plants
2. The ancient supercontinent
3. A scientists who studies fossils
4. The type of rock that may contain fossils
5. An ancient fish type found in very deep water at Sodwana Bay [5]

Question 4

Examine the two images below:

1. Suggest THREE things that fossil footprints like those in picture A can tell scientists about the animal that made them.(3)
2. Identify the fossil in picture B. (1)
3. Explain briefly how this fossil was formed.(8)
4. What can we conclude about the area where this fossil is located millions of years ago? Give a reason for your answer.(2)
5. Why is it that fossils are not found in igneous rock?(2) [16]

Question 5

Examine the fossil and graph below and answer the questions:

1. To which class of the Chordata does the fossil shown here belong? Choose from: Pisces, Amphibia, Reptilia, Aves or Mammalia.(2)
2. What does the term the “half life” of a radioactive element mean? (2)
3. When the fossil was subjected to radiometric dating, it was found to contain 90% Uranium. If the half life of Uranium 235 is 704 million years, how old is thisfossil? Show all your working.(4)
4. If another fossil was found and dated to 1408 million years, how much Uranium did it contain? Explain how you obtained your answer. (5) [13]

Question 6

Read the information below and answer the questions: Therapsid fossils from the late Permian have been found in South Africa. These animals had teeth differentiated into incisors, canines and molars, unlike reptilian teeth, which are all the same. Their legs were held more vertically, i.e. under the body, compared to what is usual in reptiles. It seems that they survived into the Mesozoic, but died out when the dinosaurs became to dominant life form.

1. Where in South Africa have therapsid fossils been found?(1)
2. Tabulate TWO ways n which therapsids are different from reptiles. (5) [6]

TOTAL 55

Suggested answers

Question 1

1. C
2. A
3. C
4. B
5. D[10]

Question 2

1. E
2. A
3. H
4. C
5. D [5]

Question 3

1. Mesozoic
2. Pangaea
3. Paleontologist
4. Sedimentary
5. Coelacanth[5]

Question 4

1. Mark 1st 3 only: Animal’s species, approximate length of leg, stride length approximate body weight, speed it moved at(3)
2. part 2
   1. Ammonite
   2. Ammonite died, sank into mud. Mud was covered by more sand and excluded oxygen. Body decayed, shell was slowly mineralized over time. Mud was compressed andbecame harder, turning to stone. Later uncovered by erosion. (max 8)
   3. It was under the sea. Ammonites were marine creatures(2)
3. Igneous rock is volcanic - lava is too hot to preserve fossils OR heat from lava destroys remains of animals(2) [ 16]

Question 5

1. Amphibia(2)
2. The amount of time needed to reduce the amount of (parent) element to half of what it was (OR the time needed for half of the element to decay / break down)(2)
3. 0,2 x 704 million = 140,8 million years(4)
4. 1408 million years ÷704 million years = 2 half lives, so the fossil had 25% Uranium 235.(5) [ 13]

Question 6

1. Karoo(1)
2. Table comparing therapsids and reptiles : (5) [6]

TOTAL 55