Unit notes and practice questions

Grade 11 Geography unit 8: Geo-spatial information and data processing

Everything here is for unit 8 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 8: 216–246
The textbook pages for unit 8

What unit 8 covers

1.Representations of relief features on topographic maps
2.Basic concepts of Geographical Information System (GIS)
3.Arcmap and main tools

Short notes for unit 8

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

Koppen Major Climate TypesReference tableA · B · C · +2

Category	Climate Type	Defining Characteristics
A	Tropical	All months average temperature above $18^\circ\text{C}$ . No real winter.
B	Dry	Deficient precipitation for most of the year. Governed by dryness.
C	Meso-thermal (Mid-latitude Mild)	Coldest month average temperature below $18^\circ\text{C}$ and above $-3^\circ\text{C}$ .
D	Micro-thermal (Mid-latitude Cold)	Warmest month exceeds $10^\circ\text{C}$ , coldest month drops below $-3^\circ\text{C}$ .
E	Polar	Average temperature of warmest month is below $10^\circ\text{C}$ . No real summer.

When you use it

Use to classify terrestrial climates into five major categories based on monthly and annual temperature and precipitation.

Watch out

Types A, C, D, and E are determined by temperature thresholds, whereas Type B is governed strictly by dryness and moisture deficit.

Drafted from Grade 11 Geography, page 2 onwards, then checked twice before it went up

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

Principle	Description
Original Horizontality	Sediments are originally deposited in horizontal beds under gravity. Non-horizontal layers indicate deformation.
Superposition	In an undisturbed sequence of sedimentary rock layers, the overlying bed is younger than the underlying bed.
Cross-Cutting Relationships	An igneous intrusion or fault that cross-cuts another rock layer is younger than the rock it cuts.

When you use it

Use when determining the chronological sequence of rock layers and geological events without exact numerical ages.

Watch out

Superposition applies strictly to undisturbed sedimentary strata. Verify if the sequence has undergone tectonic tilting or deformation.

Drafted from Grade 11 Geography, page 2 onwards, then checked twice before it went up

Radioactive Isotopes and Half-LivesReference tableUranium-238 (^238U) · Rubidium-87 (^87Rb) · Potassium-40 (^40K) · +2

Parent Isotope	Daughter Isotope	Half-Life
Uranium-238 ( $^{238}\text{U}$ )	Lead-206 ( $^{206}\text{Pb}$ )	4.5 billion years
Rubidium-87 ( $^{87}\text{Rb}$ )	Strontium-87 ( $^{87}\text{Sr}$ )	48.8 billion years
Potassium-40 ( $^{40}\text{K}$ )	Argon-40 ( $^{40}\text{Ar}$ )	1.25 billion years
Uranium-235 ( $^{235}\text{U}$ )	Lead-207 ( $^{207}\text{Pb}$ )	704 million years
Carbon-14 ( $^{14}\text{C}$ )	Nitrogen-14 ( $^{14}\text{N}$ )	5,730 years

When you use it

Use to calculate absolute numerical ages of rocks based on radioactive decay of parent isotopes into daughter products.

Watch out

Do not confuse Uranium-238, which decays to Lead-206, with Uranium-235, which decays to Lead-207.

Drafted from Grade 11 Geography, page 2 onwards, then checked twice before it went up

Practice questions on unit 8

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, approximately how many billion years ago was the Earth created from a mixture of gas and dust particles?

A.4.5 billion years ago
B.10 to 20 billion years ago
C.1.25 billion years ago
D.250 million 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

What was the name of the early supercontinent formed by the assemblage of initial landmasses around 750 Ma?

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

Show the answer and why

Answer: A Rodinia

Why

Initial landmasses gathered to form the early Neoproterozoic supercontinent called Rodinia at about 750 Ma.

Question 3

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

A.Africa
B.Asia
C.South America
D.Australia

Show the answer and why

Answer: A Africa

Why

Africa is the only continent in the world that is crossed by all three lines: the equator, the Tropic of Cancer, and the Tropic of Capricorn.

Question 4

Which oceanic trench contains the Challenger Deep, the deepest point in the world?

A.Mariana Trench
B.Puerto Rico Trench
C.Java Trench
D.South Sandwich Trench

Show the answer and why

Answer: A Mariana Trench

Why

The Mariana Trench in the Pacific Ocean contains the Challenger Deep, which is about 10,924 m deep and represents the deepest point in the world.

Question 5

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

Show the answer and why

Answer: A Principle of superposition

Why

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

Question 6

After two half-lives of radioactive decay, what percentage of the total isotopes is converted into daughter isotopes?

A.75%
B.25%
C.50%
D.87.5%

Show the answer and why

Answer: A 75%

Why

After two half-lives, 25% of the parent isotope remains, while 75% has decayed into daughter isotopes.

Question 7

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

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

Show the answer and why

Answer: A 1:4

Why

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

Question 8

Which period of the Paleozoic era was rich in fish species and is known as the age of fish?

A.Devonian
B.Cambrian
C.Silurian
D.Permian

Show the answer and why

Answer: A Devonian

Why

The Devonian period was the fourth period of the Paleozoic era and is referred to as the age of fish due to its rich abundance of fish species.

Question 9

According to the radiometric dating data in the textbook, what is the half-life of Potassium-40 (⁴⁰K) decaying into Argon-40 (⁴⁰Ar)?

A.1.25 billion years
B.4.5 billion years
C.704 million years
D.5,730 years

Show the answer and why

Answer: A 1.25 billion years

Why

Table 1.1 states that Potassium-40 (⁴⁰K) decays into Argon-40 (⁴⁰Ar) with a half-life of 1.25 billion years.

Question 10

The separation of the Indian landmass from Gondwana at about 140 Ma and its subsequent collision with Eurasia initiated the formation of which mountain range?