CHAPTER-2-THE-ENVIRONMENT-AND-ORGANISMS.pdf

CHAPTER 2 THE ENVIRONMENT AND ORGANISMS OVERVIEW In the previous chapter, you have learned about the nature of environmental science. In this chapter, the topics will focus solely on the environment and organisms. It consists o...

CHAPTER 2 THE ENVIRONMENT AND ORGANISMS OVERVIEW In the previous chapter, you have learned about the nature of environmental science. In this chapter, the topics will focus solely on the environment and organisms. It consists of two modules. In module one, you will familiarize yourself with the different ecological concepts. You will use some of your creativity for you to attain the desired outcomes. Specifically, you should creatively present the relationships between the organisms and their surroundings. In the second module, you will perform an activity that will allow you to probe the different organism’s interactions. Lastly, included in the module, and the most important part is the series of activities that will reflect the connection between organisms and the environment. Photo credit: labeltech.biz Chapter Content: ❖ Ecological Concepts ❖ Organisms Interactions CHAPTER 2 Module 1 Ecological Concepts Duration: 2 hours INTRODUCTION Photo Credit: 123RF.com The environment is dynamic because of the physical processes that drive change in the earth's features over time. In this module, you will learn about the concepts in ecology. This module deals specifically with the components of the ecosystem, which are presented within an interdisciplinary context. Also, clear linkages with the concepts from other major disciplines will be given importance. OBJECTIVES Photo Credit: Vectorstock.com Upon completion of this module, you will be able to: 1. describe the ecological hierarchy; 2. distinguish between biotic and abiotic components; and 3. explain the importance of abiotic factors to biotic components. LESSON PROPER Ecological Concepts Ecology indicates the relationship between organisms and their environment. It is the study of the ways organisms interact with each other and with their non-living surroundings.  Ecology supplements our world and is crucial for humanity. It provides resources and services vital for sustaining biodiversity, food production, quality of air, clean water, etc. Ecological Hierarchy Biosphere (The global ecosystem) Biomes (A groups of ecosystems that share similar climates and typical organisms) Ecosystem (Different communities working as a unit, interacting with both its physical and biological environment) Community (A group of different populations distributed into a specific geographical area) Population (A group of same species occupying a specific geographic area and time) Species (A group of individuals with the same genetic characteristics and is capable of interbreeding with one another)  Ecosystem refers to an interacting group of natural elements and the organisms in a given environment. It is a unit of interrelationships between biotic and abiotic factors. Thus, all living organisms depend on, influence, and adapt to nonliving components to maintain their steady-state conditions (homeostasis). Biotic Components Biotic components encompass all living organisms present in the ecosystem. These organisms are autotrophs and heterotrophs. Autotrophs are also called "self-feeders" or the “producers”. They use the energy from the sun (light energy) or chemical energy to make their food. There are two types of autotrophs. 1. Photoautotrophs are organisms that use the energy from sunlight to make their food in the process called photosynthesis. Some examples are plants, algae, and certain bacteria. Photo Credit: sactree.com 6CO + 6H O + sunlight & chlorophyll →C H O + 6O 2 2 6 12 6 2 2. Chemoautotrophs are organisms that use chemical energy from compounds to make their food in the process called chemosynthesis. Examples are some bacteria and also archaea – a microorganism that resembles bacteria.  On the other hand, Heterotrophs are called "consumers." These organisms cannot make their food, primarily animals; and get their energy from other plants and animals, and classify as: Classification Description Examples Herbivores -feed directly on plants Rabbit, Goat, -1st order/ primary consumers Cow, sheep Carnivores - that feed directly on animals Snake, Tiger -2nd order/ Secondary Eagle consumers Lion Omnivores -feed both on plants and Bears, birds, animals dogs, foxes, -1st or 2nd order consumers humans Photo Credit: Pinterest.com Furthermore, the Decomposers are also unable to make their food. They decompose waste products and dead organisms for food and are returned to the soil to be recycled and used by plants again. Bacteria and fungi are decomposers. Decomposers are classified based on the type of organic matter they break down. 1. Scavengers feed on the soft tissues of dead animals. Examples include vultures, raccoons, and blowflies. 2. Detritivores that feed on detritus - remains of plants, animal feces, and other organic debris. They can be found on the soil like earthworms, millipedes, dung beetles; and at the bottom of bodies of water such as sea cucumbers and catfish. The Abiotic Components Abiotic factors are the nonliving features of the environment that influence an organism or group of organisms. They can be organized into several categories. 1. Energy is required by all organisms to sustain life. The light energy is the ultimate source of energy for almost all organisms in ecosystems. The visible light is of the greatest importance to plants because it is essential for photosynthesis. The following factors play a crucial function in an ecosystem. 2. Atmospheric gases. The most vital gases are oxygen, carbon dioxide, and nitrogen utilized by plants and animals. Oxygen is used during animals' respiration, carbon dioxide on plant photosynthesis, and nitrogen made available by certain bacteria through various fixation processes. 3. Physical Characteristics. It includes wind or air currents, soil, pH, and temperature. 4. Physiographic factors (nature of land surface). It is associated with the physical nature of the land surface/area. It includes altitude, the slope of the land, and the area's position with the sun or rain-bearing winds. CHAPTER 2 Module 2 Organisms Interaction Duration:2 hours INTRODUCTION Photo Credit: 123RF.com Interactions among organisms come in several different forms. Organisms compete for resources, consume each other, shelter other exchange resources, etc. It denotes that organisms are part of each individual’s environment that may change species distributions and can alter ecological interactions within communities. This module is focused on ecological relationships. It will help you acquire concepts and skills in identifying the kinds of interrelationships among living organisms. Several activities and discussions are included. OBJECTIVES Photo Credit: Vectorstock.com Upon completion of this module, you will be able to: 1. identify the kinds of interrelationships among living organisms; and 2. describe how organisms interact with each other and with their environment. LESSON PROPER Photo Credit: Amazon.com ORGANISMS INTERACTION All organisms play a critical role in the ecosystem. Different categories were involved. A. Obtaining food and energy. Some organisms can make their own food (producers), and other organisms have to get their food by eating other organisms(consumers). The species that can eat many different types of foods is called a generalist. For example, raccoons eat many things, including human garbage. A specialist is a species that consumes only a specific type of food. For example, koalas only eat eucalyptus plants. B. Competition between organisms arises when more than one organism struggles to obtain the same essential resources in the same habitat. Both participants in the interaction are potentially harmed. The one who is harmed less is considered the winner, and the one who is harmed more is the loser. It controls the population size by limiting the number of organisms that can survive on the area's resources. There are two types of competition. 1. Interspecific competition happens between members of two or more different species over various limiting resources such as food, water, light, soil resources, or space. It often leads to extinction, specifically with the species that are less well-adapted, less likely to survive, and the species may go extinct. For example, predators of various species might compete for the same prey just like lions and leopards that compete for similar prey; and a farm of rice paddies with weeds growing in the field. 2. Intraspecific competition arises between members of the same species and may compete over mates, water, sunlight, territory, or food energy sources. This type of competition is a basic factor in natural selection that leads to the evolution of better adaptations. For example, two individuals of the same zooplankton species compete for nutrients in the ocean. There are three mechanisms of competition. 1. Interference competition occurs when one species directly affects the ability of another to consume resources. For example, (a) an animal may chase other individuals away from a potential food source; and (b) in some species, individuals or groups maintain and defend territories. 2. Exploitative competition occurs when one species makes a resource unavailable for consumption to another species. It is the most common mechanism of competition in nature. Examples of exploitative competition include (a) lions and cheetahs competing for gazelles on the African plains, and (b) two species of prairie grasses competing for light, soil moisture, and soil nutrients. Multiple species may compete to obtain resources that are often limited within a given habitat. As such, diverse species cannot cohabit or coexist in a community if they are competing for the same resources. According to the Competitive Exclusion Principle, “No two similar species occupy the same niche at the same time. A habitat is a place where an organism lives. It is characterized by the physical environment, including distinctive physical features, vegetation, and the group of species living in it. Conversely, each species' niche is defined by the sum of activities and relationships in which it engages to secure and use the resources necessary for its survival and reproduction. C. Predation occurs when one species uses another species as food. The organism that hunts other living things for food is called the predator, and the prey is the animal hunted by a predator. Predators have evolved various techniques to catch, subdue, or exploit their prey like fast running speed, sharp teeth and talons, and camouflage. Consequently, the prey has developed various defense mechanisms to allow them to escape and reduce their desirability as prey to their predators. Examples of these are: a. Mechanical defenses include the presence of armor in animals (spines) or thorns in plants to discourage predation and herbivory by preventing physical contact with the predator. b. Chemical defenses include odors and toxins released by plants and animals. c. Warning colors indicate aposematic coloration. d. Camouflage is protective coloration in which an animal resembles its background. e. Mimicry is when organisms resemble other species. Batesian mimicry is where a harmless species imitates a harmful one. Mullerian mimicry occurs when various species share the same warning coloration and resemble each other but have their own defenses. Watch the YouTube video entitled “Animal Defense Against Predators - Wildlife Defense (Nat Geo)” at the link https://www.youtube.com/watch?v=uqXjHw7_pAQ. D. Symbiosis describes a close and often long-term relationship between two or more different organisms. This relationship may be beneficial or harmful, or it may not affect the other organisms. The term symbiosis was first by the mycologist Heinrich Anton de Bary, who termed it "the living together of unlike organisms". Specifically, there are three basic types of symbiosis: mutualism, commensalism, and parasitism. 1. Mutualism is an interaction between two species in which both organisms benefit. An example of this is the pollination of plants by bees and other pollinators. 2. Commensalism is a type of symbiosis where one organism benefits, but the other is unaffected. For example, numerous orchids, mosses, and ferns that grow atop higher plants benefit from structural support and greater access to sunlight.  3. Parasitism is a relationship where one organism, termed the parasite, benefits at the expense of the host. Some parasites live on the surface of their host called an ectoparasite. Others live inside their host called endoparasite. Examples include tapeworms, lice, and fungus. Watch the YouTube video entitled “Extreme Animal Relationships” at the link https://www.youtube.com/watch?v=doB6fyzoO68.