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Happy EARTH Day, Happy BIRTHday!
It's BIRTH TIME across the Northern Hemisphere. As spring unfolds, Nature welcomes billions of babies--some of them in your own backyard.
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It's no coincidence that so many baby animals are born in the spring. Reproductive cycles are timed to maximize the chance of survival.
- Baby owls and hawks hatch when receding snows are exposing mice just the right size for their little mouths. By the time the babies are learning to hunt on their own a few weeks after hatching, there are lots of inexperienced other baby animals around to practice on.
- Baby hummingbirds hatch later, when there is an abundance of flowers to provide nectar and tiny insects. Think about how much food a mom and dad need every day just to feed themselves. Now imagine another whole batch of mouths to feed. For many species, spring birthdays are best.
- Many baby caterpillars hatch out right when buds are opening, when tiny leaves are very soft and succulent.
- Baby cranes hatch when vegetation is short enough that they can see their parents easily to follow them. The babies grow as fast as or faster than the grass.
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Natural
Laws: Populations and Ecosystems
Why isn't the world overrun with hummingbirds, monarchs, manatees or caribou--or
any other wild creature? Given adequate resources, and no disease or predators,
all populations increase exponentially. But throughout the natural world,
the growth of all populations are limited in specific niches in the ecosystem
by lack of resources and factors such as predation, disease, climate fluctuations,
etc.
Gaylord Nelson, founder of Earth Day, was asked his vision of the environmental
challenges facing the nation and the world. Without pause, he replied:
"Achieving stability in population growth in the U.S. and elsewhere is the most important of the hundreds of challenges facing us."
Among all species, humans have the greatest capacity to shape and adapt to our physical environment, but ALL species have one thing in common: we all depend on the Earth for survival. So on Earth Day consider what human resource use and population growth mean to all living things.
Sharing The Planet: 200,000 More People Every Day
How many people live on the planet?
How fast are humans being added to the planet? Listen carefully:
Every
time you hear a beat, it means there's another person on the planet. (This
is not the birth rate, but the "net gain," which means births
minus deaths.)
If you were to count the beats for 24 hours, 200,000 more people would
have been added to the planet.
Humankind:
The World's Most Successful Species
For hundreds of thousands of years, the human population was almost stable.
Birth and death rates were nearly even, but as this timeline shows, as
human inventions improved and extended life, birth rates increased, death
rates dropped, and the human population began to grow exponentially.
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Can
you find these historic events on the timeline?
In pre-historic times, about 5 million people lived on earth. With the
introduction of agriculture in 10,000 BC, food supplies increased, but
death rates were still high, so population growth was slow and steady.
By the year 0 there were 250 million people. Massive numbers of people
were killed when the bubonic plague struck during the 14th and 15th centuries,
and the human population declined. Suddenly, the Industrial Revolution
improved the standard of living so dramatically that the human population
began to grow exponentially. The balance was broken. In less than 200
years, the world population went from 1 billion to 6 billion people.
Inequities: Four Billion Have, Two Billion Have Not
The world is becoming an ever smaller place, making us more aware of a global ethical dilemma: Of the world's 6.3 billion people, an estimated one third live in poverty. That's 2 billion people, more people than were alive in the year 1900. (See graph.) How does an ever-growing human population makes environmental, social and political problems fundamentally harder to solve? These are complex issues with no clear answers, yet they are the most important for students to learn about the world they will inherit.
Try This! Activities and Journaling Questions
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Are humans born in specific seasons? Collect a data sample to help you find out. Ask everyone in the room what month they were born. Interview as many people as you can. Record all answers and graph the data by months. Look at the graph to see whether humans are born in specific seasons. Discuss whether the birth season is as important in the life cycle of humans as it is in the life cycle of animals. Explain your thinking.
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If there are 200,000 more people each day, how many days does it take for a million people to be added to the human population?
- What kind of footprint do you leave on Earth's resources? Take this online Ecological Footprint quiz to find out:
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2004 Journey North. All Rights Reserved.
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