Ecological Principles and Concepts

Prepared by:SERENE GRACE A. LACEA, BSEd 3- Phy SciUniversity of Bohol

Components of Ecosystem

• Ecosystems are ecological units that include all the living or biotic factors and the non-living abiotic factors in an area.

• The biotic factors include the following:– Producers or autotrophs– Consumers or heterotrophs– Decomposers

COMPONENTS OF ECOSYSTEMS

• Producers, such as plants, make food through a process called _____________.

• Producers, such as plants, make food through a process called photosynthesis.

• Producers, such as plants, make food through a process called photosynthesis.

• This food is used by the plants for its own energy or may be eaten by consumers.

• Consumers need to eat food that autotrophs have produced.

• There are different types of consumers:– Herbivores eat plants– Carnivores eat animals– Omnivores eat both plants and animals

• Decomposers are heterotrophs that break down dead tissue and waste products.

• They play a very important role in the ecosystem because they recycle nutrients.

Energy flow through ecosystem

Abiotic Factors

• Abiotic factors such as solar radiation, the atmosphere, the ocean, climate and fire also affect ecosystems.

• For a given abiotic factor, each organism living in an ecosystem has an optimal range in which it survives and reproduces.

1. Solar Radiation

• It is the electromagnetic radiation, including X-rays, ultraviolet and infrared radiation, and radio emissions, as well as visible light, emanating from the Sun.

• The Sun provides almost all the heat and light Earth receives and therefore sustains every living being.

• Solar Collecting Panels Panels on a rooftop collect energy from sunlight

and convert it directly into electricity. The solar panels contain semiconducting materials. When light strikes the material, electrons move from one layer of the material to another, forming an electric current.

• Solar energy travels to Earth through space in discrete packets of energy called ______.

• Solar energy travels to Earth through space in discrete packets of energy called photons.

• On the side of Earth facing the Sun, a square kilometer at the outer edge of our atmosphere receives 1, 400 megawatts of solar power every minute.

• Only half of that amount reaches the Earth’s surface.

• The atmosphere and clouds absorb or scatter the other half of the incoming sunlight.

• The amount of light that reaches any particular point on the ground depends on the time of day, the day of the year, the amount of cloud cover, and the latitude at that point.

• The most significant local variations in Earth’s temperature are produced because the sun’s energy does not uniformly reach all places.

2. The Atmosphere

• The atmosphere is an invisible layer of gases that envelops Earth.

• It is composed of oxygen (21%) and nitrogen (78%) or 99% of dry air.

• Other gases including argon, carbon dioxide, neon, and helium make up the remaining 1%.

Divisions of the Atmosphere

• In addition, water vapor and various air pollutants, such as methane, ozone, dust particles, pollen, microorganisms and chlorofluorocarbons (CFC) are present.

• The atmosphere protects the Earth’s surface from sun’s ultraviolet radiation and x-rays and from lethal amounts of cosmic rays from space.

3. The Ocean

• The ocean surrounds the continents and covers almost three fourths of the Earth’s surface.

• The pacific ocean is largest covering one third of the Earth’s surface and contains more than half of the Earth’s water.

• The prevailing winds blowing over the ocean produce mass movements of surface ocean water known as ocean currents.

• The prevailing winds generate circular ocean currents called gyres.

• The Coriolis forces cause ocean currents to move clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

Major surface currents of the world’s oceans

4. Climate

• Climate is the average conditions, and the extremes that occur in a given place over a period of years.

• The two most important factors that determine an area’s climate are:– Temperature– Precipitation

• Other climate factors include wind, humidity, for, cloud cover, and fire.

• Unlike weather, climate generally changes slowly, over hundreds or thousands of years.

• Latitude, elevation, topography, vegetation, distance from the ocean and other large bodies of water, all influence temperature, precipitation, and other aspects of climate.

• Precipitation varies from one location to another and has a profound effect on the distribution and kinds of organism present.

• One of the driest place on Earth is in the Atacama Desert in Chile, where the average annual rainfall is 0.05 cm and the wettest portion on Earth is in Mount Waialeale in Hawaii with an average annual precipitation of 1200cm.

5. Microclimates

• The differences in elevation, in the steepness and direction of slopes and their exposure to sunlight and prevailing winds may produce local variations in climate known as microclimates.

• Microclimates are sometimes quite different from the overall surroundings.

• The patches of sun and shade on a forest floor, produce a variety of microclimates for plants, animals, and micro-organisms living there.

• The microclimate of an organism’s habitat is of primary importance because that is the climate an organism actually experience and most cope with.

6. Fire

• Fires have several effects on organism.

• First, combustion frees the nutrient minerals that were locked in dry organic matters.

• The ashes remaining after the fire are rich in potassium, phosphorus, calcium, and other nutrient minerals essential for plant growth.

• Secondly, fire removes plant cover and exposes the soil.

• This change stimulates the germination and establishment of seeds requiring bare soil, as well as encourages the growth of shade- tolerant plants.

• Thirdly, fire causes increased in soil erosion because it removes plant cover, leaving the soil more vulnerable to wind and water.

Factors that influence the distribution of plants and animals

1. Temperature- the ability to withstand extremes in temperature widely vary among animals.

• Animals respond to variation in temperature both physiologically and behaviorally.

• Birds and mammals are endotherms and maintain relatively high blood temperatures using the heat by their own metabolism

• Ectotherms use sources of heat such as solar radiation and conduction to help adjust their body temperature.

• Endotherms maintain body temperature by:– Changing the position of fur or feathers sweating

and panting– Shivering– By behavioral means such as seeking shade or

water, burrowing, or varying periods of activity.

• Endotherms may avoid extended periods of low or high temperature by hibernating or estivating.

• Hibernation is winter dormancy.

• Estivation is summer dormancy.

• Plants cannot move to escape high and low temperatures.

• Photosynthesis slows down or stops when temperature get too high or too low.

• Plants that are adapted to withstand low temperatures may have hairs on leaves or stems.

• These plants tend to be short and grow closely together to resist the cold temperature and wind.

• They tend to be dark colored to absorb as much of the sun’s heat as possible.

2. Water

• Precipitation along with mean temperature determines the distribution of biomes.

• The primary problem of plants in areas like desert is lack of water.

• Plants adapted for arid conditions include:– xerophytes such as cacti usually have special means of

storing and conserving water– Phreatophytes, plants that grow extremely long roots,

allowing them to acquire moisture at or near the water table.

3. Light

• Light is necessary for photosynthesis which in turn is the source of energy in almost all ecosystems

• Light affects animals directly since they are able to detect their prey or enemies through the sense of sight.

• Body organs that are sensitive to light, like the eyes are present in almost all animals from the simplest forms to the highest forms.

• The penetration of light into the ocean determines the depth at which plants can grow.

• Algae and phytoplanktons are most abundant at the water surface where light is available.

• Only animals that depend on animals can live at the bottom of the ocean.