Part2 ecosystem

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The premier University in historic Cavite recognized for excellence in the development of globally competitive and morally upright individuals.

CvSU Mission

Cavite State University shall provide excellent, equitable and relevant educational opportunities in the arts, sciences and technology through quality instruction and responsive research and developmental activities. It shall produce professional, skilled and morally upright individuals for global competitiveness.

CAVITE STATE UNIVERSITY(CvSU)

Imus Campus

General EcologyPART II: ECOLOGICAL PRINCIPLES & CONCEPTS

I. CHARACTERISTICS

Living organisms and their nonliving environment are inseparably interrelated and interact upon each other. Any unit that includes all of the organisms (biotic) in a given area interacting with the physical environment (abiotic) which leads to clearly defined trophic structure, biodiversity, and material cycles in a system is known as Ecological System or Ecosystem.

Biosphere is the global ecosystem or the sum of all the planet’s ecosystems. Biodiversity is the degree of variation of life forms within a given species, ecosystem,

biome, or planet. It includes genetic diversity, species diversity, and ecosystem diversity.

Types of Ecosystem1. Aquatic Ecosystem

Marine Freshwater

2. Terrestrial Ecosystem Forest Grassland Dessert Urban

II. STRUCTURAL COMPONENTS OF AN ECOSYSTEM

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Minerals

EcosystemEcosystem

Abiotic

Climatic

Rain

Light

pH

TemperatureSoil

pH

Edaphic

Topography

Producers

Consumers

Biotic

Decomposers

CvSU Vision

The premier University in historic Cavite recognized for excellence in the development of globally competitive and morally upright individuals.

CvSU Mission

Cavite State University shall provide excellent, equitable and relevant educational opportunities in the arts, sciences and technology through quality instruction and responsive research and developmental activities. It shall produce professional, skilled and morally upright individuals for global competitiveness.

CAVITE STATE UNIVERSITY(CvSU)

Imus Campus

Abiotic Components

Abiotic components (also called abiotic factors) are non-living chemical and physical factors in the environment which affect ecosystems.

Example: There is a significant difference in access to water as well as humidity between temperate rainforests and deserts. This difference in water access causes diversity in the types of plants and animals that grow in these areas.

Energy Source Lack of sunlight is seldom the most important factor limiting plant growth for

terrestrial ecosystems. Although shading by trees does create intense competition for light among plants growing on forest floor.

In many aquatic environments, light cannot penetrate beyond certain depths and as a result, most photosynthesis in a body of water occurs near the surface.

Hydrothermal vents are strange ecosystems that lie deep under the ocean. They are adjoining edges of giant plates of Earth’s crust where molten rocks and hot gases surge upward from Earth’s interior. This ecosystem is powered by chemoautotrophic bacteria that drive energy from oxidation of inorganic chemicals such as hydrogen sulfide (pictures available on the site).

Temperature Temperature is an important abiotic factor because of its effect on metabolism.

Metabolism refers to the total of all chemical reaction of an organism. Few organisms can maintain a sufficiently active metabolism at temperatures

close to 0oC, and temperatures above 45oC destroy the enzymes of most organisms.

Thermopiles are organisms that thrive at relatively high temperatures, between 45 and 122 °C. Thermophilic bacteria are suggested to have been among the earliest bacteria and are found in various geothermally heated regions of the Earth such as hot springs and see deep hydrothermal vents (pictures available on the site).

Water For terrestrial organisms, the primary threat is drought. Many land species have

watertight coverings that reduce water loss. A waxy coating (cuticle) on the leaves and other aerial parts of most plants helps prevent dehydration (pictures

available on the site). Aquatic organisms are surrounded by water, but they face problems of water

balance if their own solute concentration does not match that of their surroundings (application of the principle of osmosis).

Nutrients Plants obtain inorganic nutrients such as compounds of nitrogen and phosphorus

from the soil. Soil structure, pH and nutrients play major roles in determining the distribution of plants.

In aquatic ecosystems, low levels of nitrogen and phosphorus limit the growth of producers like algae and photosynthetic bacteria.

Oligotrophic environment refers to ecosystems which have very little nutrients to sustain life.Eutrophic environment refers to ecosystems which are rich in nutrients to sustain life.

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CvSU Vision

The premier University in historic Cavite recognized for excellence in the development of globally competitive and morally upright individuals.

CvSU Mission

Cavite State University shall provide excellent, equitable and relevant educational opportunities in the arts, sciences and technology through quality instruction and responsive research and developmental activities. It shall produce professional, skilled and morally upright individuals for global competitiveness.

CAVITE STATE UNIVERSITY(CvSU)

Imus Campus

Other Aquatic Factors Dissolved oxygen in water Salinity Currents Tides

Other Terrestrial Factors Wind Natural / Phenomenal Disturbances

Biotic Components

Trophic (trophe which means feeding or nourishment) level of organisms is the position it occupies in a food chain.

1. Producers They are autotrophic organisms. Autotrophs are organism that produces complex

organic compounds from simple substances present in its surroundings, generally using energy from light (photosynthesis) or inorganic chemical reactions (chemosynthesis).

Photoautotrophs / Phototrophs are autotrophic organisms that use the energy from light to carry out various cellular metabolic processes. In terrestrial environments, plants are the predominant phototrophic variants while aquatic environments include a range of phototrophic organisms such as algae (kelp or seaweeds), other protists (euglena), phytoplankton, and bacteria (cyanobacteria or blue-green algae).

Chemoautotrophs use inorganic energy sources, such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia. These are the chemoautotrophic bacteria in Hydrothermal vents and thermophilic bacteria.

2. Consumers They are also called macroconsumers or phagotrophs (phago means to eat)

which ingest other organisms or particulate organic matter. They are either directly or indirectly dependent on Autotrophs.

Classification of Consumers (Food Chain Perspective)2.1. Primary Consumers are Herbivores or animals which are directly

dependent and feed on autotrophs. 2.2. Secondary Consumers are carnivores or animals which feed on primary

consumers. Carnivores derive its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue. Omnivore which feeds on both plants and animals, can also be considered a secondary consumer.

2.3. Tertiary Consumers also known as an Apex Predator are usually on top of food chains capable of feeding on secondary consumers and primary consumers. Tertiary consumers can be either fully carnivorous or omnivorous. Humans are example of a tertiary consumer.

Consumers are also heterotrophic organisms. Heterotrophs are organisms that cannot fix carbon and uses organic carbon for growth.

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CvSU Vision

The premier University in historic Cavite recognized for excellence in the development of globally competitive and morally upright individuals.

CvSU Mission

Cavite State University shall provide excellent, equitable and relevant educational opportunities in the arts, sciences and technology through quality instruction and responsive research and developmental activities. It shall produce professional, skilled and morally upright individuals for global competitiveness.

CAVITE STATE UNIVERSITY(CvSU)

Imus Campus

Classification of Heterotrophs (Depending on Energy Source)2.1. Photoheterotrophs are heterotrophic organisms that use organic

compounds from the environment to satisfy their carbon requirements.2.2. Chemoheterotrophs utilize organic compounds both as a carbon source

and an energy source. They break down complex organic compounds like carbohydrates, fats, and proteins produced by autotrophs into simpler compounds like glucose, fatty acids and glycerol, and amino acids. Examples of these are animals.

Saprotrophic nutrition is a chemoheterotrophic digestion which involves breaking down dead or decaying organisms (known as detritus)

3. Decomposers They are also called Saprotrophs that carry out the natural process of

decomposition. Decomposers use dead organisms and non-living organic compounds as their food source.

Detritivore utilizes decomposing material. Examples of these are bacteria and fungi. Bacteria are vital in the recycling of nutrients such as nitrogen by Nitrogen-fixing bacteria.

Scavenger eats decaying flesh. Examples of these are vultures, scavenging birds. Worms can also act as scavengers.

III. PRODUCTION AND DECOMPOSITION IN NATURE

Biomass is the mass of living biological organisms in a given area or ecosystem at a given time.

Production or Productivity refers to the rate of generation of biomass in an ecosystem. Primary production is the synthesis of new organic material from inorganic molecules

such as H2O and CO2. It is dominated by the process of photosynthesis which uses sunlight to synthesis organic molecules such as sugars, although chemosynthesis represents a small fraction of primary production. Organisms responsible for primary production include land plants, marine algae and some bacteria (cyanobacteria)

Secondary production is driven by the transfer of organic material between trophic levels and represents the quantity of new tissue created through the use of assimilated food. Organisms responsible for secondary production include animals, protists, fungi and many bacteria.

Decomposition is the natural process of dead animal or plant tissue being rotted or broken down. The result of decomposition is that the building blocks required for life can be recycled. During the process of decomposition, the decomposers provide food for themselves by extracting

chemicals from the dead bodies or organic wastes using these to produce energy. The decomposers will then produce waste of their own. In turn, this will also decompose, eventually returning nutrients to the soil. These nutrients can then be taken up by the roots of living plants enabling them to grow and develop, so that organic material is naturally recycled. Virtually nothing goes to waste in nature. When an animal dies and decomposes, usually only the bones remain, but even these will decompose over a much longer period of time.

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CvSU Vision

The premier University in historic Cavite recognized for excellence in the development of globally competitive and morally upright individuals.

CvSU Mission

Cavite State University shall provide excellent, equitable and relevant educational opportunities in the arts, sciences and technology through quality instruction and responsive research and developmental activities. It shall produce professional, skilled and morally upright individuals for global competitiveness.

CAVITE STATE UNIVERSITY(CvSU)

Imus Campus

IV. PROCESSES IN ECOSYSTEM

Nutrient Cycling or Ecological Recycling is the reuse of chemical elements within the ecosystem. This includes Carbon Cycle, Nitrogen Cycle, Phosphorus Cycle, and Water Cycle.

Energy Flow is the passage of energy through the components of the ecosystem.

V. HOMEOSTASIS

Ecosystems are capable of self-maintenance and self-regulation as are their component populations and organisms.

Abiotic factors can increase or decrease the amount of environmental stress on an ecosystem and therefore can also affect the stability of that ecosystem.

Scene 1: High stress, less stable environmentThe intertidal zone is the shore area that is submerged at high tide and exposed at low tide. It is rich in oxygen and nutrients and provides a home for many different species. The organisms that live in this area are constantly exposed to a high stress, less stable environment. However, they have adapted to huge daily changes in moisture, temperature, turbulence (from the water), and salinity. They have to be used to living in both wet and dry conditions continually.

Scene2: Low stress, more stable environmentJungles are very stable environments that possess some 40% of all species. It is also a very diverse environment consisting of several layers of organisms using different parts of the ecosystem. As well as increasing biodiversity, jungles are beneficial to increasing our knowledge of medicinal plants and increasing oxygen output.

Disturbance, succession and biodiversity also affect ecosystem function.Disturbance is a temporary change in average environmental conditions.Ecological Succession is the observed process of change in the species structure of an

ecological community over time.

ADDITIONAL REFERENCE

1Simon, E.J., Reece, J.B., Dickey, J.L. 2010. Campbell Essential Biology, 4th ed. Pearson Education Inc

Prepared by

Ms. SHELA B. LEBASNONInstructor I

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CvSU Vision

The premier University in historic Cavite recognized for excellence in the development of globally competitive and morally upright individuals.

CvSU Mission

Cavite State University shall provide excellent, equitable and relevant educational opportunities in the arts, sciences and technology through quality instruction and responsive research and developmental activities. It shall produce professional, skilled and morally upright individuals for global competitiveness.

CAVITE STATE UNIVERSITY(CvSU)

Imus Campus

Date: June 28, 2013

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