Understanding Environmental Impact and Human Development

Understanding the Environment

The environment is a set of physical, chemical, biological, and social components and their interactions.

Environmental Impact

Environmental impact refers to the changes, both direct and indirect, caused by human activity on the environment, such as farming or building highways.

Environmental Problems

An environmental problem occurs when human aggression toward the environment leads to negative repercussions for ecosystems, human health, or the integrity of natural systems. These problems often arise from the extraction of resources to satisfy the needs of an exponentially growing human population.

Natural Resources

A resource is any natural component of the environment, including energy and raw materials, used by people. Resources are classified as:

• Renewable Materials: Materials that replenish at a high or low rate.
• Non-Renewable Materials: Materials that do not replenish.
• Renewable Energy: Energy derived from natural sources.
• Non-Renewable Energy: Energy from sources that deplete over time.

Contamination

Contamination is any change in the characteristics of water, soil, air, or food that negatively affects health or the survival of living beings. There are two types of contaminants: chemical substances and energy.

The Greenhouse Effect

1. Increased consumption of fossil fuels.
2. Combustion produces CO2.
3. Increased concentration of CO2 in the atmosphere.
4. CO2 and other gases prevent heat output, increasing the Earth's average temperature.

Acid Rain and Ozone Depletion

Acid Rain: Air emissions of nitrogen oxides and sulfur fall as acid rain.

Ozone Depletion: The presence of CFC gases in the stratosphere combines with and destroys the ozone layer.

Human Reproduction and Development

Fecundation: The fusion of an egg and sperm results in the first cell of a new individual, the zygote.

Nesting: The embryo enters the uterus and implants into the uterine lining.

Placentation: Through the placenta, there is an exchange of substances between maternal blood and the embryo.

Stages of Gestation

• 1 Month: Measures 1mm; the heart starts beating.
• 2 Months: Brain creation starts; the fetus grows to 30mm and takes on a human aspect.
• 3 Months: Fetus is 56mm, can move, sex is recognizable, and the circulatory system is active.
• 4 Months: The body is formed and skeletal maturation begins.
• 5 Months: The nervous system matures and fetal movements are perceived.
• 6 Months: Bronchi and lungs are created.
• 7 Months: Possesses the organs necessary to live outside the mother's womb.
• 8 Months: Completes fetal growth.