3° Human adaptations

HUMAN ADAPTATIONS

Innovation and Science

What is?

Scientific evidence shows that the physical and behavioral traits shared by all people originated from ape-like ancestors and evolved over a period of approximately six million years.

what is natural selection?

Natural selection is the process by which populations of living organisms adapt and change. This means that some individuals have traits that are better adapted to the environment than others.

Charles Darwin: Father of the theory of natural selection

Over time, these advantageous traits become more common in the population. Through this process of natural selection, favorable traits are passed down through the generations.

Natural selection can lead to "SPECIATION", in which one species gives rise to a new and different species. It is one of the processes that drives evolution and helps explain the diversity of life on Earth.

HUMAN ADAPTATIONS

The human body readily responds to changing environmental stresses. This ability to adapt quickly to different environmental conditions has enabled us to survive in most regions of the world. Humans normally respond to environmental stresses in four ways:

• Developmental Adjustment

• Genetic Change

• Cultural Practices and Technology

• Acclimatization

• Genetic change

Individuals who inherit a trait that offers an advantage in responding to certain stresses are more likely to survive longer and pass on more of their genes to the next generation.

An example of a genetic solution to environmental stress is our ability to produce sweat to help cool our bodies in hot environments.

This occurs in childhood and usually results in anatomical and/or physiological changes that are mostly irreversible in adulthood.

• Developmental Adjustment

An example was the custom of tightly wrapping or binding girls' feet. This resulted in permanent and disabling deformities to the bones of the feet

Anatomical and/or physiological adjustments can also develop over even shorter periods of time.

• Acclimatization

Many people acquire skin tanning during the summer months and lose it during the winter. This change in skin coloration is a seasonal acclimation to the destructive effects of ultraviolet radiation from the sun.

• Cultural Practices and Technology

For the last half a million years, we have invented technological aids that have allowed us to occupy new environments without first having to evolve biological adaptations to them.

For example, houses, clothing and fire allowed us to live in temperate regions

Let's watch the next video!

Activity

TREE FELLING

1. One forester and three lumberjacks will be selected, the other students will be trees.
2. The lumberjacks will have one minute to cut down the trees, if they touch them they will stay on the ground while the forester plants another tree.
3. The trees will have to stand up in parts, first sitting, then kneeling and finally standing up again.
4. As they stand up, the foresters will be able to cut them down again.
5. A forester will be added every minute until the 5 minutes are up. Finally, the number of variations will be counted: Number of trees felled VS number of foresters.