Unit notes and practice questions

Grade 11 Geography unit 4: Global population dynamics and challenges

Everything here is for unit 4 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.

3
Cards: 10
Practice questions on unit 4: 96–122
The textbook pages for unit 4

What unit 4 covers

1.The growth of world population
2.Factors responsible for accelerated population growth
3.International migrations
4.Population policies

Short notes for unit 4

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

Geological Eras of the EarthReference tablePrecambrian · Paleozoic · Mesozoic · +1

Geological Era	Age Range (Ma)	Major Characteristics and Life Forms
Precambrian	$4500\text{ to }600$	Earth solidification, oldest basement complex rocks, continental shields, covers 85 percent of Earth time.
Paleozoic	$600\text{ to }250$	Ancient life, trilobites, age of fish, assembly of supercontinent Pangaea, mass amphibian extinction.
Mesozoic	$250\text{ to }70$	Middle life, age of dinosaurs, Pangaea rifting into Laurasia and Gondwanaland, first mammals and birds.
Cenozoic	$70\text{ to present}$	Recent life, age of mammals, flowering plants, mountain building, Ice Age, modern humans.

When you use it

Use to review the major divisions of Earth history, their age boundaries, and their evolutionary milestones.

Watch out

Precambrian is the oldest and longest era, taking up about 85 percent of geological time, not Paleozoic.

Drafted from Grade 11 Geography, page 1 onwards, then checked twice before it went up

Principles of Relative DatingReference tableOriginal Horizontality · Superposition · Cross-Cutting Relationships

Principle	Definition
Original Horizontality	Sedimentary rock layers are originally deposited horizontally under the action of gravity.
Superposition	In an undisturbed sedimentary sequence, overlying beds are younger than underlying beds.
Cross-Cutting Relationships	A rock layer or igneous intrusion that cuts across another rock layer is younger than the rock it cuts.

When you use it

Use to determine the chronological order of rock layers without using numerical ages.

Watch out

The principle of superposition applies strictly to undisturbed rock sequences.

Drafted from Grade 11 Geography, page 1 onwards, then checked twice before it went up

Radioactive Decay ProportionsReference table0 · 1 · 2 · +1

Half-lives	Parent Isotope (%)	Daughter Isotope (%)
$0$	$100$	$0$
$1$	$50$	$50$
$2$	$25$	$75$
$3$	$12.5$	$87.5$

When you use it

Use to track the remaining parent and accumulating daughter isotope percentages through successive half-lives.

Watch out

With each half-life cycle, the parent isotope decreases by half while total daughter percentage increases to keep the sum at 100 percent.

Drafted from Grade 11 Geography, page 1 onwards, then checked twice before it went up

Practice questions on unit 4

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 Big Bang theory presented in the textbook, about how many billion years ago was the Earth formed from a mixture of gas and dust particles?

A.4.5 billion years ago
B.10.0 billion years ago
C.15.5 billion years ago
D.20.0 billion years ago

Show the answer and why

Answer: A 4.5 billion years ago

Why

The textbook states that Earth was created from the mixture of gas and dust particles moving in space around the Sun about 4.5 billion years ago.

Question 2

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

A.Principle of original horizontality
B.Principle of superposition
C.Principle of cross-cutting relationships
D.Principle of radioactive decay

Show the answer and why

Answer: B Principle of superposition

Why

The principle of superposition asserts that in an undisturbed sequence of sedimentary layers or lava flows, each overlying bed is younger than the rock layer beneath it.

Question 3

What is the deepest point in the world, located in the Pacific Ocean?

A.Challenger Deep
B.Puerto Rico Trench
C.Java Trench
D.South Sandwich Trench

Show the answer and why

Answer: A Challenger Deep

Why

The deepest point in the world is the Challenger Deep within the Mariana Trench in the Pacific Ocean, reaching a depth of about 10,924 meters.

Question 4

In the ancient Greek climate classification, which zone represents the warm tropical area south of the Mediterranean Sea?

A.Frigid Zone
B.Torrid Zone
C.Temperate Zone
D.Polar Zone

Show the answer and why

Answer: B Torrid Zone

Why

The ancient Greeks used the Torrid Zone to represent the tropics, which were the warm areas south of the Mediterranean Sea.

Question 5

What is the name of the early supercontinent that gathered together at about 750 Ma before the formation of Pangaea?

A.Laurasia
B.Gondwanaland
C.Rodinia
D.Baltica

Show the answer and why

Answer: C Rodinia

Why

According to the textbook, the initial landmasses gathered to form the early Neoproterozoic supercontinent called Rodinia at about 750 Ma.

Question 6

During radioactive decay, what stable daughter isotope does Potassium-40 (⁴⁰K) convert into?

A.Argon-40 (40Ar)
B.Nitrogen-14 (14N)
C.Lead-206 (206Pb)
D.Strontium-87 (87Sr)

Show the answer and why

Answer: A Argon-40 (40Ar)

Why

The decay table shows that the parent isotope Potassium-40 (⁴⁰K) decays into the daughter isotope Argon-40 (⁴⁰Ar) with a half-life of 1.25 billion years.

Question 7

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

A.1:1.5
B.1:4
C.4:1
D.1:1

Show the answer and why

Answer: B 1:4

Why

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

Question 8

According to the Köppen climate classification, which temperature condition defines a Tropical climate (Type A)?

A.All months have an average temperature above 18 degrees Celsius
B.The warmest month has an average temperature below 10 degrees Celsius
C.The coldest month average drops below -30 degrees Celsius
D.Average temperature remains below freezing throughout the entire year

Show the answer and why

Answer: A All months have an average temperature above 18 degrees Celsius

Why

In Köppen's system, a Tropical climate (A) is defined by all twelve months having an average temperature above 18 degrees Celsius (64 degrees Fahrenheit), meaning there is no real winter.

Question 9

A student in Addis Ababa analyzes a rock sample in a laboratory. The test shows that 25% of the original parent isotope remains and 75% has converted into daughter isotopes. How many half-lives have passed?

A.1 half-life
B.2 half-lives
C.3 half-lives
D.4 half-lives

Show the answer and why

Answer: B 2 half-lives

Why

After 1 half-life, 50% of the parent isotope remains. After 2 half-lives, the parent isotope is halved again to 25%, while the daughter isotope reaches 75%.

Question 10

During which geological era did Pangaea split into Laurasia and Gondwanaland, accompanied by the dominance of dinosaurs?

A.Precambrian era
B.Paleozoic era
C.Mesozoic era
D.Cenozoic era

Show the answer and why

Answer: C Mesozoic era

Why

The Mesozoic era (250 to 70 Ma) is known as the age of dinosaurs and was the time when Pangaea split into Laurasia and Gondwanaland.

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

The textbook pages for unit 4

Unit 4 runs from page 96 to page 122 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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