Ecology: Food Chains, Trophic Levels & Populations

• Part 1 of the environmental science class discusses the environment and its components.
• The environment consists of ecosystems, human population, and urbanization.

What is Environmental Science?

• Environmental science involves the interaction of the earth through how it works.
• It deals with environmental problems and ways to live more sustainably.
• It is an interdisciplinary study that involves science, ethics, economics, and other fields.
• Environmental science differs from Environmentalism, which a social movement dedicated to protecting Earth's life, found more in politics and ethics.
• Sustainability is the ability of the Earth's natural and human systems to survive and adapt to changing environmental conditions indefinitely.

Principles of Sustainability

• Three important lessons from nature
• Solar energy warms the earth and enables food production for plants, humans and animals.
• Solar energy powers indirect forms of energy like wind and flowing water, which generates electricity.
• Biodiversity is the biological variety and variability of life on Earth, encompassing evolutionary, ecological, and cultural processes that sustain it.
• Many ecosystems exist, the world's species and ecosystems renew soil, purify air, and supply water.
• Chemical cycling involves natural processes that recycle nutrients, which is necessary because the Earth has a fixed nutrient supply.

Natural Capital and Degradation

• Natural capital is a combination of natural resources and natural services.
• Natural resources are materials and energy in nature essential or useful to humans, and which can be classified as renewable, nonrenewable, or inexhaustible.
• Natural services are processes in nature, like purification, pollination, or nutrient cycling, that support life.
• Ecosystem services are vital for sustaining human life and maintaining ecosystem balance, the services include supporting, provisioning, cultural and aesthetic, and regulating.
• Processes in nature such as purification or air, water and pollination. Nutrient cycling is one of the vital natural services.
• Ecological footprint measures how fast we consume resources and generate waste compared to how fast nature can absorb our waste and generate new resources.
• Ecological deficit exists if a country's total ecological footprint exceeds its biocapacity to replenish resources and absorb pollution.
• Tipping point between unsustainable practices and environmental effects can cause environmental problems to build slowly until the threshold, which is known as ecological tipping point.

Ecosystems

• Biomes are categorized into terrestrial and aquatic types.
• Terrestrial biomes are based on land, while aquatic include both ocean and freshwater biomes.
• There are 8 major terrestrial biomes, distinguished by temperature and amount of precipitation.
• Freshwater ecosystems include rivers, streams,lakes, ponds, and wetlands.
• Marine ecosystems include oceans and estuaries.

Productivity

• This depends on how much solar energy that the producers can capture and store as chemical energy, and determining biomass that a ecosystem supports.
• Gross primary productivity is the rate at which ecosystems' producers convert solar energy into chemical energy, measured over a given time.
• Net primary productivity measures how fast producers can produce stored chemical energy, potential energy available to other organisms.
• Trophic levels refer to producers (autotrophs), consumers (heterotrophs) and decomposers.
• Terrestrial producers: plants (photosynthesis) .
• Aquatic producers: algae and aquatic plants near shorelines, phytoplankton dominant producers in open waters
• Primary consumers are herbivores, secondary and tertiary consumers are carnivores.
• Omnivores can eat plants and other animals.
• Decomposers release nutrients from dead organic matter.
• Biomass is the dry weight of all organic matter in organisms.

Human Population and Urbanization

• Human population growth continues and it is unevenly distributed.
• 95% of 2.6 billion people likely to be added to the world's population between 2011 and 2050, come from Least Developed Countries.
• Cultural carrying capacity is the maximum number of people that live in indefinite comfort without decreasing Earth's sustainability for future generations.

Population Trends of the Philippines

• As of August 22nd, 2020, the approximate population of the Philippines based on UN data is 109,782,500.
• The Philippines' population in 2020 was estimated at 109,581,078.
• Equivalent to 1.41% of the entire world population.
• The Philippines is 13th in the list of countries by its population.
• The population density in the Philippines is 368 per Km².
• Total land area is 298,170 Km2.
• 47.5% of population is urban.
• The median age in the Philippines is 25.7 years.

IPAT Model

• The IPAT equation (I = P x A x T) shows the key factors causing environmental degradation.
• Impact = Population x Affluence (consumption per person) x Technology (impact per unit of concumption).

Factors That Affect Population Size

• Birth rate.
• Death Rate.
• Total fertility rate estimates the average number of children per woman of childbearing age (15-44).
• Migration refers to the increase in population size due to people moving into a certain geographical area, Immigration is the traveling into a place. Emigration is the traveling out of a place.
• Availability of family planning and birth control methods.
• Cultural norms surrounding family planning and sex.
• The pandemic.

Economic Factors That Affect Natality and Fertility

• Include the importance of children as labor, the cost of raising children, the availability of public pension systems, educational and employment opportunities for women, urbanization, average marriage age, access to legal abortions and reliable birth control, and religious and cultural beliefs.

Economic Factors Affecting Death Rates

• Best measure a society's quality of life because it reflects a country's general level of nutrition and health care.
• Infant mortality rate: the average number of years a newborn infant can be expected to live

Age Structure

• A population's age structure helps create projections.

Slowing Population Growth

• Reduce poverty.
• Elevate the status of women.
• Encourage family planning and reproductive health care.

Urbanization Trends

• Cities and Migration - An increasing percentage of the world's people live in urban areas.
• Urban Development.
• Urbanization is the process by which large people becomes permanently concentrated in relatively small areas.
• Urban areas increase rapidly–births and immigration.
• Numbers and sizes of urban areas.
• Urban sprawls affect rural and forested areas, causing natural Capital Degradation.

Explore energy flow in food chains and the roles of producers, consumers, and decomposers. Investigate trophic levels, biomass transfer, and human impact. Understand the relationship between urbanization and natality rates, as well as factors influencing quality of life and population growth.