General Biology I Lecture 04 PDF

B A ZE UN IVERSITY A B UJA BAZE UNIVERSITY ABUJA DEPARTMENT OF BIOLOGICAL SCIENCES General Biology I BIO 101 LECTURE 04...

B A ZE UN IVERSITY A B UJA BAZE UNIVERSITY ABUJA DEPARTMENT OF BIOLOGICAL SCIENCES General Biology I BIO 101 LECTURE 04 By MRS FATIMA MAIRAMI INERRELATIONSHIP OF ORGANISM CONTENTS 4.0 – Introduction 4.1- Interrelationship of Living Organisms 4.2- Producers, Consumers, and Decomposers. 4.3- Food Chain and Food Web 4.4- Pyramid of Energy and Pyramid of Biomas 1 4.0 – Introduction This is a study of the interrelationships between living organisms and the non-living components and processes that make up the global environment. Ecology is study of the interrelationships between living organisms and the non-living components and processes that make up the global environment. Living organisms do not exist in isolation; they interact with each other and their environment in various ways, creating complex relationships that shape ecosystems. Biosphere: The worldwide system within which all life functions. It includes the atmosphere (air), hydrosphere (water) and the lithosphere (soils, rocks) Biome: The biome is the major ecological region within which plant and animal species are similar in general characteristics and in their relationships to the physical environment. E.g. Tundra, Deserts, Forests Grasslands etc. 4.1- Non feeding relationship between Living Organisms All living organisms interact and are interdependent on each other and their environment for food, shelter, energy, survival, reproduction, and to establish a stable ecological balance. No living organism can survive in isolation. An Ecological relationship: - is the relationship between organisms in an ecosystem. All organisms in an ecosystem are connected to one another. Each interaction depends on the one before it. Each population interacts with one another in a complex web of relations. Ecological relationships help better describe how they are connected. There are six ecological relationships in which two are oppositional and four are symbiotic.The oppositional relationships are predation and competition. The symbiotic relationships are mutualism, commensalism, amensalism, and parasitism. The ecological relationship an organism has depends on the way the organism adapted to its environmental pressures on evolutionary bases. The environment or ecosystem is an area where all the biotic (the living components of the environment i.e., plants, animals and micro-organisms) and abiotic (the non-living components of the environment i.e., soil, water, elements of weather etc.,) parts interact. 2 These types of relationship may be of interspecific or intraspecific categories. The different types of associations are discussed below.  Saprotropism: Saprotrophalso called saprophyte or saprobe, organism that feeds on nonliving organic matter known as detritus at a microscopic level.Saprotrophic organisms are considered critical to decomposition and nutrient cycling and which include fungi, certain bacteria, and funguslike organisms known as water molds (phylum Oomycota).In this type of association one type of organism is living, while the other is dead organic matter. Living organisms grow on the dead and decaying organic bodies like wood, bread, lemon etc. and take their nutritive elements from those dead organic materials. Saprophytic nutrition is found in non-green plants which draw their nourishment from dead matters. Saprophytes may be of two types: Total and Partial. Total saprophytic organisms (fungi) completely depend on the dead and decaying substances for nutrition. E.g., Mucor, Agaricus.  Antagonism: In ecology is an association between organisms in which one benefits at the expense of the other. As life has evolved, natural selection has favoured organisms that are able to efficiently extract energy and nutrients from their environment. Because organisms are concentrated packages of energy and nutrients in themselves, they can become the objects of antagonistic interactions. Although antagonism is commonly thought of as an association between different species, it may also occur between members of the same species through competition and cannibalism.In this type of interaction either one or both type of organisms are harmed. This association is subdivided into following categories: 1.Parasitism: Parasitism is a type of symbiotic relationship, or long-term relationship between two species where one member, the parasite, gains benefits that come at the expense of the host member. In this type of relationship one type of organism is benefited and other is harmed. In this category of heterospecific association one organism (Parasite), lives at the expense of other associated organism (Host). Among plant kingdom Dodder (Cuscuta reflexa) collects its nutritive elements from the host plant with the help of sucking root called Haustoria. Among kingdom Animalia two types of parasites are found: ectoparasite (living outside the host body) and endoparasite (living inside the host body). Round worm is an 3 endoparasite living inside the human small intestine and draw nutrition as endoparasite, but Louse is an ectoparasite and it lives outside the human body i.e. on the outer body surface. 2. Exploitation: Exploitation is defined as the act of using resources or the act of treating people unfairly in order to benefit from their efforts or labor. Making use of natural resources to build a city is an example of the exploitation of those resources. In this type of relationships one organism enslaves the other organism. 3. Predation: Predation is the ecological process by which energy is transferred from living animal to living animal based on the behaviour of a predator that captures and kills a prey before eating it. Predators occupy the upper levels of food chains. This top position helps explain their generally low density, frequently spaced distribution, and usually small total biomass. In terms of conservation, this is sometimes critical for the survival of local predator populations. In this type of association one organism catches and kills the other organism for food. E.g., as tiger catches deer, Pitcher plant catches insects for food, Human catches fishes, etc. 4. CommensalismIs any relationship between organisms of different species in which one organism is inhibited or destroyed while the other organism remains unaffected.In this type of relationship the chemical secretion of an organism's body harms the other, but no nutrition takes place. The chemical secretion in some microorganisms is called Antimicrobial. Penicillin is an antibiotic produced from the fungus Penicillium notatum that kills the bacterium Staphylococcus. 5. Competition: In this type of nutrition two organisms when living in a specific ecosystem compete with each other for food and shelter.Competition is when organisms compete for the same resources. This is a negative relationship because both organisms are harming each other.There are two types of competition with living organisms:- Interspecies competition Intra species competition is the competition between members of the same species over limited resources such as food, water, shelter, or mates. 4  Members of the same species have similar needs, thus they frequently fight for these resources. 1. Limited Resources: Individuals from the same species require the same resources for survival and reproduction. When these resources are scarce, competition develops. 2. Natural selection: is driven by intra species competition, which ensures that only the fittest individuals survive and reproduce, passing on their advantageous features to the next generation. 3. Impact on Population: This form of rivalry has the potential to limit population growth. If resources are excessively few, the population may decline. Organisms competing can be from within the same species for example, two male elk fighting for a female mate. Elephants also fight each other so that the dominant elephant will get to breed with the female. Interspecies Competition Interspecies competition occurs when individuals from various species fight for limited resources in an ecosystem, such as food, water, space, or light. This form of rivalry can be detrimental to the survival and reproduction of both competing species. 1. Different Species: Interspecies competition occurs when two or more species fight for the same resource, potentially leading to one species being outcompeted or pushed to adapt. 2. When resources are scarce, species compete to acquire enough to survive and reproduce. This often results in a struggle for domination or specialization. 5  3. Niche Differentiation: To lessen competition, species may evolve to occupy slightly different ecological niches, utilizing different resources or residing in separate locations. Examples: a. Lions and hyenas competing for prey in the same habitat. b. Different plant species competing for sunlight in a dense forest. Interspecies competition plays a critical role in shaping community structure and can drive evolutionary changes as species adapt to reduce competition. Competition can be also found in two different species. A lizard and a frog can compete for a similar food they eat such as a small insect. This type of competition is only found when two different species share an ecological niche that they must compete over.  Symbiosis: In this type of relationship living organisms live together and help one another. It is mainly of three categories: 1. Commensalism: In this type of association one organism may be benefited and the other may remain neutral but no one is harmed. Fireasfer fish lives inside the cloacal cavity of Sea cucumber to protect itself from the attack of predators. Here no one is harmed, but the Fireasfer fish is protected. 2. Mutualism: It is an obligatory relationship between two organisms where both individuals benefit from each other and are interdependent on one another. The association between the algae Zoochlorella and hydra is an example of mutualism where both mutually benefit from each other. Lichen is the result of a union between a green alga and a fungus. The fungus gains oxygen & carbohydrates from the alga, while the alga also obtains water, carbon dioxide and mineral salts from the fungus. 6 3. Protocooperation: Is a facultative relationship between two organisms, where both individuals benefit from each other, but can also live independently. The association between hermit crab and sea anemone is an example of protocooperation.  Neutralism: This is one type of relationship between / among two or more type (s) of organism (s) where they live together but neither are they benefited nor harmed. In the freshwater bodies this type of relationship is found between Hydra and Phytoplankton. 4.2- Categories of Organisms in the ecosystems. All ecosystems contain three basic types of organisms: producers, consumers and decomposers. Each type of organism plays a vital role in the ecosystem. If one of the three types of organisms were to disappear, all living things would die as the cyclical flow of life-giving energy collapsed.In most ecosystems living organisms are categorized based on the roles(ecological niche) they play in their habitata particular environment within the ecosystem in which an organism lives. Ecological nicheis defined as the role of a species in an ecosystem. Based on that living organisms could be classified into:  Producers (authotrophs):Although the three types of organisms work together in a cycle of energy, it is easiest to think of producers as the organisms that begin the cycle. Producers take energy from inorganic sources and convert it into sugars. Green plants are producers that take energy from the sun and create sugars through photosynthesis. Deep-sea bacteria are also producers; they live near vents in the ocean’s floor and convert chemicals into sugar. Producers are autotrophs because they are at the base of the food chain (also known as trophic levels).  Consumers (heterotrophs): Consumers are the organisms that consume energy from producers. Insects and animals are consumers, and there are 7  three types within this category. Herbivores are primary consumers because they eat only autotrophs (plants). Carnivores then consume these herbivores (insects and animals). If a carnivore only eats herbivores, it is a secondary consumer. A carnivore that eats the secondary consumer would be a tertiary consumer. Omnivores, such as humans, consume both autotrophs and herbivores.  Decomposers (saprothrophs): Decomposers are the final type of organism in an ecosystem. All producers and consumers eventually die and become detritus. The decomposers then consume this lifeless detritus and convert it into vital inorganic material. Decomposers return this inorganic material to the environment where it provides important nutrients for producers. Thus, the cycle begins again as nutrients provided by decomposers sustain producers, consumers feed on the producers and decomposers reintroduce the remaining energy.organisms that obtain nutrients and chemical energy by breaking down the remains of dead plants and animals. They pole very vital roles in the biogeochemical cycle of elements, by converting organic compounds into inorganic compounds and elements. Examples include fungi, bacteria, etc. 4.3- Feeding Relationship amongh Organisms Food Chain and Food Web 8 A food web is a series of interacting food chains. Food chains show the order in which animals consume food.Within an ecosystem, there is a pathway of energy flow that always begins with the producers, and ends with the consumer, forming a food relationship. A food chain – is a series of organism through which food energy is passed. A food chain only follows just one path of energy flow as animals find food. Food chain While a food web – consists of many food chains connected together, showing the several paths of energy flow among organisms. 9  Food web 4.4-Pyramid of Energy and Pyramid of Biomass The amount of energy available in a food web decreases with each higher feeding level, as a result of loss in form of heat; incomplete digestion and absorption. Hence only about 10% of the energy taken in any feeding level is passed to the next feeding level. A pyramid of energy: shows the amount of energy present in an ecosystem. Where the greatest amount of energy is present at the base of the pyramid (producers), and the least energy is present at the top of the pyramid (highest level consumers). 10  Graphic diagrams of pyramids Energy Pyramid of Biomass: shows the relative mass of organisms (biomass) at each feeding level. Since the total amount of energy available decreases with each higher feeding level, the total biomass that can be supported at each level decreases, too Graphic diagrams of pyramidsBiomass Maintenance in an Ecosystem: For an ecosystem to be stable and self- sustaining the following conditions must exist - there must be: 11  1. Constant source of energy (sunlight, chemosynthesis); 2. Organisms that can synthesis incoming energy into organic compounds; 3. Cycle of materials between organisms and the environment. Ecological Succession: is the process by which an existing community is slowly replaced by another community. Change occurs because some of the living organisms present in the ecosystem alter the environment to suit themselves. Succession could be: (i) primary – when succession occurs in an area that has no existing life, e.g., bare rocks; and (ii) secondary – is succession that occurs in an area in which an existing community has been partially destroyed, and its balance upset. Questions. 1. Write short notes on the following  Antagonism  Mutualism  Protocooperation 12   Commensalism  Neutralism 2. Explain the term symbiosis. Mention examples of this association. 3. Statethe difference between food chain and food web? 4. List and explain the categories of organismsin ecosystems. 5. What is ecological relationship in an ecosystem? List the different types of ecological relationship in an ecosystem. 6-Write short notes on the following:-  Intraspeciescompetition  Interspeciescompetition 13