Population Pyramids Answer Key
Teacher Answer Key & Scoring Guide Unit 2 • TEKS WG.7A & WG.22A
Population Pyramid Graphing Template
Master Solution Key & Comparative Benchmarks (Nigeria • USA • Japan)
Total Points
70 pts
(or scale to 50: score × 0.71)
1 Graph Rules & Quick Setup — Scoring Checklist
10 Points
1. Males on LEFT 3.5 pts
Shades horizontal bars left from center 0 line (blue/pencil).
Extends leftward only
2. Ages in CENTER 3.0 pts
0–14 at bottom tier; 75+ at top tier. No axis inversion.
0–14 base / 75+ top
3. Females on RIGHT 3.5 pts
Shades horizontal bars right from center 0 line (red/purple).
Extends rightward only
2 Graph Solutions & Visual Benchmarks (20 Points)
Scale accuracy: 10 pts • Proportions & bars: 10 pts
Option 1
NIGERIA
Stage 2 • Rapid
Wide base; acute tapered apex.
← M (Blue) AGE F (Red) →
75+
50-74
25-49
15-24
0-14
Key Targets:
• 0–14: Bars past 20% mark (22% M / 21% F).
• 75+: Tiny sliver (<1% each side).
Option 2
UNITED STATES
Stage 4 • Slow
Vertical column; steady tiers.
← M (Blue) AGE F (Red) →
75+
50-74
25-49
15-24
0-14
Key Targets:
• 0–14: ~9% (just below 10% marker).
• 75+: ~3.5%–4.5% (substantial senior tier).
Option 3
JAPAN
Stage 5 • Shrinking
Inverted cup; pinched youth base.
← M (Blue) AGE F (Red) →
75+
50-74
25-49
15-24
0-14
Key Targets:
• 0–14: Narrow base (~6%).
• 75+: Very broad apex (6.5% M / 9.5% F).
Common Student Graphing Deductions:
• Swapped Sexes: Females on left or males on right (-4 pts)
• Inverted Age Axis: 75+ plotted at base instead of top (-5 pts)
• Origin Drift: Starting bars from margins instead of center 0 (-4 pts)
• Missing Color Differentiation: Pencil only used for both sides (-2 pts)
World Geography Assignment • Unit 2 Human Geography Key Part 1 Solutions: Rules & Graph Grid Page 1 of 2
Teacher Scoring Rubric & Model Answers
Population Pyramid Analysis (Part 2)
Sections 3, 4 & 5
Part 2 Max: 40 pts
3 Shape Diagnosis & Growth Classification
10 Points
Triangle (Rapid) NIGERIA
Very wide base; sharp pointed top. Booming youth population.
✓ Correct match for Nigeria
Box / Column (Slow) USA
Straight vertical sides. Balanced births and deaths.
✓ Correct match for USA
Inverted Cup (Shrink) JAPAN
Pinched narrow base; bulging top of elderly seniors.
✓ Correct match for Japan
4 Government Advisor: Future Budget Needs
15 Points
1. Youth Needs: Build new elementary schools & pediatricians? 7.5 pts
Nigeria (YES - High Priority) 43% youth base requires massive investment in new schools, teacher hiring, vaccines, and pediatric clinics to serve rapid population expansion.
USA (MODERATE / STABLE) Stable youth cohort (~18%) needs steady maintenance and modernization of existing schools; no massive nationwide emergency expansion required.
Japan (NO - Surplus/Closures) Plummeting birth rates (<12% youth) cause school closures and consolidations. Budget should pivot away from building new elementary facilities.
2. Senior Needs: Nursing homes, pensions, or young workers as seniors retire? 7.5 pts
Nigeria (LOW IMMEDIATE NEED) Only ~1.8% over 75. Priority is jobs for youth. Family networks care for elders; national pension/nursing crises are not immediate fiscal threats.
USA (RISING PRESSURE) Baby Boomers retiring demand increased Social Security solvency, Medicare expansion, assisted living beds, and young replacement workers.
Japan (ACUTE CRISIS) 16% over 75 (29% over 65). Severe shortage of eldercare homes, pension deficits, and heavy reliance on caregiver automation and guest workers.
5 They Can't Leave Without... (Exit Ticket Rubrics & Exemplars)
15 Points
A. Why called a "pyramid," and why do some modern countries look like boxes or cups? 7.5 pts
Exemplar Answer: Historically, populations had high birth rates and high death rates at older ages, creating a wide base that sharply tapered upward like an Egyptian pyramid. Today, modern developed nations have lower fertility rates (family planning) and higher life expectancy (medicine/sanitation), equalizing cohorts into "boxes" (slow growth) or pinched "cups" (shrinking youth with large elderly bulges).
• Historical shape explained (2.5 pts) • Low birth rate impact explained (2.5 pts) • High life expectancy explained (2.5 pts)
B. Compare Nigeria & Japan: In 20 years, which country will have a bigger workforce shortage? 7.5 pts
Exemplar Answer: Japan will experience a severe workforce shortage. In 20 years, its large 50–74 age bracket will enter retirement, while its tiny youth cohort (only ~11.6% today) is far too small to replace them. In contrast, Nigeria's huge youth population (43% under 15) will enter prime working age, providing a vast labor supply (demographic dividend) rather than a worker shortage.
• Identifies Japan (2.5 pts) • Analyzes Japan's retiring bulge vs. tiny youth base (2.5 pts) • Explains Nigeria's large youth pipeline (2.5 pts)
Grading Conversion:
A: 63–70 pts (90–100%) B: 56–62 pts (80–89%) C: 49–55 pts (70–79%) Needs Revision: <49 pts (<70%)
World Geography Assignment • TEKS WG.7A & WG.22A Complete Teacher Scoring Guide & Exit Ticket Key Page 2 of 2