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Lesson 1: Ecosystem (Fourth Quarter Period)
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- 3. Living things likeus depend on other living and nonliving things found in your environment for food, shelter, protection, and reproduction. Our environment is made up of everything that surrounds us.
- 5. BASIC COMPONENTS OFAN ECOSYSTEM All the living and nonliving things that you interact with in your environment make up an ecosystem. The living things are known as the biotic components while the nonliving things are the abiotic components of the ecosystem.
- 7. BIOTIC COMPONENTS The bioticcomponents of an ecosystem include the producers, consumers, and decomposers.
- 8. PRODUCERS Organisms capable ofmaking their own food. Thus they are also called autotrophs or “self – feeders”. They only require inorganic nutrients and the energy from the sun to synthesize sugar and other organic compounds in their bodies.
- 10. CONSUMERS Organisms that cannotmake their own food. Thus, they are also called heterotrophs or “other feeders”. They depend on the food made by other organisms for their survival.
- 12. Organisms that feeddirectly on producers are called first order. Animals that eat first – order consumers are called second order. Consumers that feed on second – order consumers are called third order consumers.
- 13. The succession ofconsumers from the producers is one of the most complex networks of interaction among organisms in an ecosystem.
- 14. Herbivores, such ascows and horses, feed on plants. Carnivores, such as tigers and lions, eat the flesh of other animals. Omnivores, like humans, feed on both plants and animals. Scavenger is a consumer that feeds on the tissues of dead animals.
- 15. DECOMPOSERS Also called saprotrophs,are microorganisms that cause plants and animals to decay and release substances that are reused by green plants or producers. Many inorganic compounds needed by producers may not be readily available if there were no decomposers.
- 17. ABIOTIC COMPONENTS Ecosystem donot only involve interactions among living organisms. They also constitute the nonliving or abiotic components that influence these interactions. They include physical factors of of the environment.
- 18. For instance, producerslike plants and other chlorophyll – bearing organisms need solar energy to make their own food through the process called photosynthesis.
- 19. Animals and non– chlorophyll – bearing organisms are also influenced by abiotic factors. Other abiotic factors such as soil, rocks and minerals depend on water, the universal solvent, for them to be used by living things.
- 20. ECOLOGICAL RELATIONSHIPS IN ANECOSYSTEM A relationship may be beneficial or harmful to the ecosystem, but the overall effect is dynamic balance among the organisms and the populations that make up the ecosystem. Some interactions tend to over – lap with one another; some are part of a larger interaction.
- 21. AMENSALISM The relationship inwhich one population is inhibited while the other one is not affected. The antibiotic inhibited the growth of one species but did not affect the growth of the other species.
- 23. COEVOLUTION Occurs when twoor more interacting members of a community evolve in such a manner that they end up matching one another in terms of physical features.
- 25. COMPETITION Takes place whenmembers of the same or different species attempt to use resources that are limited in supply and end up competing for these resources.
- 27. HERBIVORY The process wherebyan animal eats a plant or plantlike organisms. Organisms that feed on plants are called herbivores or grazers.
- 29. PREDATION Involves a violent fightbetween predator and prey, with one killing the other to survive. The predator seeks, kills, and eats its prey to prolong his own life. The prey is the organism that the predator takes as food.
- 31. SCAVENGING A unique relationshipbetween two organisms and takes place when a living organism feeds on the remains of a dead animal.
- 33. SYMBIOSIS Most species survive because oftheir “amicable” relationships with other species. One such relationship is symbiosis, in which a close and permanent association exists between organisms of different species.
- 35. MUTUALISM A mutual relationshipis one in which both organisms benefit from the relationship.
- 37. PARASITISM With parasitism, anorganism lives on or in another organism that is typically bigger. There is a parasite and a host.
- 39. A parasite that livesoutside its host’s body is an ectoparasite. The one that lives within the host body is an endoparasite.
- 40. COMMENSALISM The relationship whereinone organism benefits without harming nor affecting another organism.
- 42. ENERGY TRANSFER INAN ECOSYSTEM The existence of an ecosystem is entirely dependent on the energy that circulates among the producers and consumers in it. To be able to function, an ecosystem has to have energy, which is derived from the sun.
- 43. THE FOOD CHAIN Thesequence that shows the feeding relationships between the organisms in the different trophic levels of an ecosystem. The trophic levels are the positions that different organisms occupy in the food chain. These levels are divided into the first, second and third levels.
- 45. Producers form thefirst trophic level of the biotic community. These plants are eaten by consumers, the second trophic level made up of animals that eat the producers.
- 46. Herbivores make upthe primary consumers while carnivores, which eat herbivores, are considered secondary consumers. The latter consumers are eaten by higher – order animals called tertiary consumers.
- 47. THE FOOD WEB Anorganism in one food chain can belong to other food chains. In turn, different food chains can be grouped to form a complex interrelationship called food web. Unlike the food chain, the food web shows that organisms have more than one source of food.
- 49. THE ENERGY PYRAMID Fewerorganisms are found as you go higher in the food chain. A pyramid of numbers shows this clearly. Some organisms may be small but very numerous, so population size may not be a good measure of how much of an organism there is in a habitat.
- 52. The energy inthe pyramid, also called food pyramid, illustrates the distribution of energy in an ecosystem.
- 53. It shows thatenergy is maximized at the producer level, and decreases with increasing consumer levels. Generally, the amount of energy transferred from one organism to another is reduced to about 10%.
- 54. This can beexplained by the fact that organisms use some of the energy to maintain life processes, while releasing some energy into the environment as heat. The energy pyramid further suggests that due to the minimal amount of energy received, only few carnivores are sustained in a food web.