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Unit notes and practice questions

Grade 11 Geography unit 1

Everything here is for unit 1 of the Grade 11 Geography textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.

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3
Cards
10
Practice questions on unit 1
1–26
The textbook pages for unit 1

What unit 1 covers

  1. 1.Formation of the continents and oceans
  2. 2.Geological timescale
  3. 3.Distribution of the continents and oceans
  4. 4.Changing position of the continents and oceans

Short notes for unit 1

The cards filed under this chapter on the Grade 11 Geography page. Open one at a time.

Geological EraTime Span (Ma)Dominant Life and Key Events
Precambrian4500−6004500 - 600Earth solidified, oldest rocks formed, basement complex and shields created
Paleozoic600−250600 - 250Ancient life, trilobites, age of fish, Pangaea supercontinent formed by the end
Mesozoic250−70250 - 70Age of dinosaurs, first mammals and birds, Pangaea split into Laurasia and Gondwanaland
Cenozoic70−070 - 0Age of mammals and modern humans, orogenic folding, continents attained present positions

When you use it

Use this to classify Earth history into major eras and link each era to its characteristic life forms and tectonic events.

Watch out

Pangaea assembled at the end of the Paleozoic era, but broke apart during the Mesozoic era.

Drafted from Grade 11 Geography, pages 2-27, then checked twice before it went up

OceanRank by SizeDeepest PointDeepest Depth
Pacific Ocean1stMariana Trench (Challenger Deep)10924 m10924\text{ m}
Atlantic Ocean2ndPuerto Rico Trench8605 m8605\text{ m}
Indian Ocean3rdJava Trench (Sunda Trench)7258 m7258\text{ m}
Southern Ocean4thSouth Sandwich Trench7235 m7235\text{ m}
Arctic Ocean5thNansen Basin (Central Basin)4665 m4665\text{ m}

When you use it

Use this to compare the five ocean basins by surface area ranking and match each ocean with its deepest trench.

Watch out

The Southern Ocean is delimited from parts of the Pacific, Atlantic, and Indian Oceans, making it the fourth largest, not the smallest.

Drafted from Grade 11 Geography, pages 2-27, then checked twice before it went up

PrincipleCore Rule
Original HorizontalitySedimentary layers are originally deposited in nearly horizontal beds under gravity.
SuperpositionIn undisturbed rock layers, the overlying bed is younger than the underlying bed.
Cross-cutting RelationshipsA rock layer or igneous intrusion that cuts across another is younger than the rock it cuts.

When you use it

Use these principles to determine the chronological sequence of sedimentary rock layers and igneous intrusions.

Watch out

Superposition applies only to undisturbed strata. Deformed or overturned layers do not follow the bottom-is-older rule.

Drafted from Grade 11 Geography, pages 2-27, then checked twice before it went up

Practice questions on unit 1

10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.

Question 1

According to the textbook, about how many billion years ago was the Earth formed from gas and dust particles around the Sun?

  1. A.2.5 billion years ago
  2. B.3.5 billion years ago
  3. C.4.5 billion years ago
  4. D.10.0 billion years ago
Show the answer and why

Answer: C 4.5 billion years ago

Why

The Earth was formed from a mixture of gas and dust particles moving in space around the Sun about 4.5 billion years ago.

Question 2

Which geological principle states that in an undisturbed sequence of sedimentary rock layers, the overlying bed is younger than the underlying rock?

  1. A.Principle of original horizontality
  2. B.Principle of superposition
  3. C.Principle of cross-cutting relationships
  4. D.Principle of radioactive decay
Show the answer and why

Answer: B Principle of superposition

Why

The principle of superposition asserts that in undisturbed rock layers, older rocks lie at the bottom and younger rocks lie on top.

Question 3

Which continent is the only one in the world crossed by the equator, the Tropic of Cancer, and the Tropic of Capricorn?

  1. A.Asia
  2. B.South America
  3. C.Africa
  4. D.Australia
Show the answer and why

Answer: C Africa

Why

Africa is the second largest continent and the only continent crossed by all three lines: the equator, the Tropic of Cancer, and the Tropic of Capricorn.

Question 4

Which ocean contains the Challenger Deep inside the Mariana Trench, which is the deepest point in the world?

  1. A.Atlantic Ocean
  2. B.Indian Ocean
  3. C.Pacific Ocean
  4. D.Arctic Ocean
Show the answer and why

Answer: C Pacific Ocean

Why

The Pacific Ocean is the largest ocean and contains the Challenger Deep within the Mariana Trench at a depth of about 10,924 meters.

Question 5

During radioactive decay, what percentage of the original parent isotope remains after two half-lives have passed?

  1. A.50%
  2. B.25%
  3. C.12.5%
  4. D.75%
Show the answer and why

Answer: B 25%

Why

After one half-life, 50% of the parent isotope remains. After two half-lives, the remaining parent amount is halved again to 25%.

Question 6

What is the ratio of land to ocean in the Northern Hemisphere compared to the Southern Hemisphere?

  1. A.1:1.5 in the Northern Hemisphere and 1:4 in the Southern Hemisphere
  2. B.1:4 in the Northern Hemisphere and 1:1.5 in the Southern Hemisphere
  3. C.1:2 in the Northern Hemisphere and 1:3 in the Southern Hemisphere
  4. D.1:1 in the Northern Hemisphere and 1:5 in the Southern Hemisphere
Show the answer and why

Answer: A 1:1.5 in the Northern Hemisphere and 1:4 in the Southern Hemisphere

Why

The ratio of land to ocean is about 1:1.5 in the Northern Hemisphere and 1:4 in the Southern Hemisphere.

Question 7

According to the textbook, at about what time did the supercontinent Pangaea divide into Gondwanaland and Laurasia?

  1. A.At about 750 Ma
  2. B.At about 390 Ma
  3. C.At about 160 Ma
  4. D.At about 65 Ma
Show the answer and why

Answer: C At about 160 Ma

Why

At about 160 Ma, Pangaea divided into two large landmasses called Gondwanaland and Laurasia through continental drift.

Question 8

What does the principle of cross-cutting relationships state about rock layers?

  1. A.Sediments are always deposited horizontally under gravity.
  2. B.A rock layer that cross-cuts another rock layer is younger than the rock it cuts.
  3. C.The bottom layer of sedimentary rock is always the oldest.
  4. D.Unstable parent isotopes decay into stable daughter isotopes at a constant rate.
Show the answer and why

Answer: B A rock layer that cross-cuts another rock layer is younger than the rock it cuts.

Why

The principle of cross-cutting relationships states that any feature or intrusion that cuts across another rock layer must be younger than the rock it cuts.

Question 9

In the geological timescale, which period of the Paleozoic era was rich in fish species and is often called the age of fish?

  1. A.Cambrian
  2. B.Silurian
  3. C.Devonian
  4. D.Permian
Show the answer and why

Answer: C Devonian

Why

The Devonian period, the fourth period of the Paleozoic era, was rich in fish species and is referred to as the age of fish.

Question 10

Which radioactive parent isotope converts into Argon-40 (40Ar) with a half-life of 1.25 billion years?

  1. A.Potassium-40 (<sup>40</sup>K)
  2. B.Rubidium-87 (<sup>87</sup>Rb)
  3. C.Uranium-235 (<sup>235</sup>U)
  4. D.Carbon-14 (<sup>14</sup>C)
Show the answer and why

Answer: A Potassium-40 (<sup>40</sup>K)

Why

Potassium-40 (40K) decays into Argon-40 (40Ar) with a half-life of 1.25 billion years.

The app holds 12 questions on this unit, marked as you go. These are the first 10.

The textbook pages for unit 1

Unit 1 runs from page 1 to page 26 of the Ministry of Education edition.

Ministry of Education edition, English, 254 pages

Download the PDF

All Grade 11 Geography short notes

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