Solved Human Population Worksheet Estimated Human Population ... - Free Printable

Let’s go step by step to solve this worksheet.

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Step 1: Graph the Human Population Over Time (Question 1)

You are given a table with years and population in millions. You need to plot these points on the graph provided.

Here’s how to do it:

- The x-axis is labeled “Year” — from 0 to 2100.
- The y-axis is labeled “Population (in Millions)” — from 0 to 8000.
- For each row in the table, find the year on the x-axis, then go up to the correct population number on the y-axis, and put a dot there.
- Then connect the dots with a smooth line (or straight lines between points).

Example:
- Year 1 → Population 170 million → Find “1” on x-axis (very close to 0), go up to 170 on y-axis → mark point.
- Year 200 → 190 → find 200 on x-axis, go up to 190 → mark point.
- Continue for all rows.

Note: Some numbers like 6060 (year 2000) or 7965 (2025) are very high — they’ll be near the top of the graph.

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Step 2: Add a dashed line projecting to 2100 (Question 2)

We need to estimate what the population might be in 2100.

Look at recent growth:

- 2000: 6060
- 2007: 6625 → increase of 565 in 7 years → about 80 per year
- 2025*: 7965 → from 2007 to 2025 is 18 years → increase of 1340 → about 74 per year

So growth rate has slowed slightly but still increasing.

From 2025 to 2100 = 75 years.

If we assume average growth of ~70 million per year (a bit less than before, since growth slows as population gets huge):

70 × 75 = 5250

Add that to 2025 population:
7965 + 5250 = 13,215 million

But wait — the graph only goes up to 8000! That means our projection will go OFF the chart if we use linear growth.

Actually, most experts believe human population will peak around 10–11 billion (10,000–11,000 million) by 2100, then maybe stabilize or decline.

The UN projects about 10.4 billion (10,400 million) by 2100.

Since the graph stops at 8000, you can’t draw 10,400 — so perhaps the teacher expects you to extend the trend *within* the graph? But that wouldn’t be accurate.

Wait — look again at the data:

From 1950 (2556) to 2025 (7965) — that’s 75 years, growth of 5409 → avg ~72/year.

If we keep that same rate until 2100 (another 75 years):

7965 + (72 × 75) = 7965 + 5400 = 13,365

Still way over 8000.

BUT — here’s the key: population growth is slowing down. It’s not linear anymore — it’s curving downward (logistic growth). So we should NOT just add the same amount every year.

Better approach: Look at the pattern.

From 1900 to 2000: 1625 → 6060 → big jump
From 2000 to 2025: 6060 → 7965 → smaller jump relative to size
So future jumps will get even smaller.

Many scientists think population will reach about 10,000–11,000 million by 2100, then stop growing.

Since your graph only goes to 8000, you have two choices:

A) Draw the dashed line going off the top of the page (if allowed)
B) Assume the teacher wants you to project within the scale — which would mean underestimating.

But looking at the instructions: “Add a dashed line of your projection for the size of the human population through the year 2100.”

It doesn’t say “stay on the graph,” so you can draw it going above 8000 — just label it clearly.

However, since the grid stops at 8000, maybe you’re supposed to estimate based on visible trend?

Alternative idea: Maybe the student is expected to notice that growth is slowing and project a curve that flattens out.

Let me check actual projections:

According to United Nations (as of 2024), world population is projected to reach:

- 9.7 billion in 2050
- 10.4 billion in 2100

That’s 10,400 million.

So for Question 2: Draw a dashed line starting from 2025 (7965) and curving upward more slowly, reaching about 10,400 by 2100 — even though it’s off the chart. If you must stay on the chart, write “>8000” at the end.

But since the instruction says “through the year 2100”, and the graph includes 2100 on x-axis, probably you’re meant to extrapolate beyond 8000 visually — just don’t worry about exact scaling past 8000.

In class, teachers often accept reasonable estimates.

I’ll go with 10,400 million as a realistic projection.

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Step 3: Reasons for your projection (Question 3)

Why did I choose 10,400 million?

Because:

- Birth rates are falling worldwide — especially in developed countries.
- More people are living longer, but fewer babies are being born.
- Countries like Japan, Italy, Germany already have shrinking populations.
- Even in Africa, where growth is fastest, birth rates are dropping due to education and family planning.
- Experts (like the UN) study this carefully and predict slow growth after 2050, peaking around 2100.
- Resources like food, water, space may limit further growth.
- Climate change and disease could also affect population.

So my reason: “I used current trends showing slower growth and expert predictions that population will peak around 10–11 billion by 2100.”

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Now, let’s double-check everything.

Graphing: Just plot the points — no math needed there.

Projection: From 2025 (7965) to 2100 — 75 years.

If we assume growth slows:

- Next 25 years (to 2050): maybe +2.4 billion → 7965 + 2400 = 10,365
- Then next 50 years (to 2100): almost no growth → stays around 10,400

Yes, matches UN projection.

Final Answer for Q2: Dashed line to ~10,400 million by 2100.

Final Answer for Q3: Because birth rates are declining globally, many countries are aging, and experts predict population will peak around 10–11 billion by 2100 due to limited resources and social changes.

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Final Answer:

For Question 1: Plot all given data points on the graph and connect them with a solid line.

For Question 2: Draw a dashed line starting from 2025 (7965 million) and rising gradually to approximately 10,400 million by 2100. Since the graph only goes to 8000, extend the line above the grid and label it “~10,400”.

For Question 3: My projection is based on global trends showing declining birth rates, increased access to education and healthcare, and expert forecasts (like the UN’s) that human population will peak around 10–11 billion by 2100 due to resource limits and societal changes.