Environmental Biology and Toxicology Notes PDF

Quadrant II – Transcript and Related Materials Programme: Bachelor of Science (Third Year) Subject: Zoology Paper Code: ZOC 109 Paper Title: Environmental Biology and Toxicology Unit: 01 Introduction to Environmental Biology Module Name: Definition of Ecology and Environmental biology...

Quadrant II – Transcript and Related Materials Programme: Bachelor of Science (Third Year) Subject: Zoology Paper Code: ZOC 109 Paper Title: Environmental Biology and Toxicology Unit: 01 Introduction to Environmental Biology Module Name: Definition of Ecology and Environmental biology Name of the Presenter: Ms. Soniya Dessai Notes DEFINITION OF ECOLOGY: “It is scientific study of the relationship between organisms and their environment at different levels of biological organization” History of Ecology: The word ‘ecology’ (oekologie), first proposed by Earnst Haeckel (1869), a German Biologist, is derived from Greek words, oikos meaning the dwelling place or home and logos meaning the discourse or study; thus, the word ecology literally means the study of living organisms, both plants and animals in their natural habitats or homes. Danish botanist, Eugenius Warming elaborated the idea of Ecology. Ramdeo Misra is revered as the Father of Ecology in India CLASSIFICATION OF ECOLOGY: Ecology may be divided into autecology and synecology: Autecology: Autecology is concerned with the study of individual animal or plant species or its population throughout its life history in relation to the habitat in which it grows. In other words, it is a study of inter-relationship between individual species or its population and its environment. Ecology is the study of ecosystems or the totality of the reciprocal interactions between living organisms and their environment Synecology: The other area of ecology which deals with systems of many species—whole communities or major fractions of communities and ecosystems is termed Synecology in English speaking countries, or biocenology or bio- sociology by many Europeans. (Whittaker, R.H. 1970). It deals with the study of communities, their composition, their behavior and relation with the environment It is further divided into 3 types:  Population Ecology  Community Ecology  Ecosystem Ecology Types of Ecology Global Ecology: It deals with interactions among earth’s ecosystems, land, atmosphere and oceans. It helps to understand the large-scale interactions and their influence on the planet. Landscape Ecology: It deals with the exchange of energy, materials, organisms and other products of ecosystems. Landscape ecology throws light on the role of human impacts on the landscape structures and functions. Ecosystem Ecology: It deals with the entire ecosystem, including the study of living and non-living components and their relationship with the environment. This science researches how ecosystems work, their interactions, etc. Community Ecology: It deals with how community structure is modified by interactions among living organisms. Ecology community is made up of two or more populations of different species living in a particular geographic area. Population Ecology: It deals with factors that alter and impact the genetic composition and the size of the population of organisms. Ecologists are interested in fluctuations in the size of a population, the growth of a population and any other interactions with the population. In biology, a population can be defined as a set of individuals of the same species living in a given place at a given time. Births and immigration are the main factors that increase the population and death and emigration are the main factors that decrease the population. Organismal Ecology: Organismal ecology is the study of an individual organism’s behaviour, morphology, physiology, etc. in response to environmental challenges. It looks at how individual organisms interact with biotic and abiotic components. Ecologists research how organisms are adapted to these non-living and living components of their surroundings. Individual species are related to various adaptations like physiological adaptation, morphological adaptation, and behavioral adaptation. Molecular Ecology: The study of ecology focuses on the production of proteins and how these proteins affect the organisms and their environment. This happens at the molecular level. DNA forms the proteins that interact with each other and the environment. These interactions give rise to some complex organisms. COMPONENTS OF ECOLOGY The main aim of ecology is to understand the distribution of biotic and abiotic factors of living things in the environment. The biotic and abiotic factors include the living and non-living factors and their interaction with the environment. Abiotic components of ecosystem It includes inorganic and organic compounds of the environment or habitat of the organism. Most important abiotic components of an ecosystem are Light, Temperature, Water, Soil and Air Light:- Light is the most vital factor without which no life can exist. Light coming in the form of radiant energy from the sun is the source of energy for every ecosystem. Plants by the process of photosynthesis change this light energy into chemical energy which is needed by every living thing. Distribution of plants and animals is affected by the type, intensity and exposure time of light. Temperature:- Temperature decreases at higher altitudes and higher latitudes and fauna and flora changes accordingly. Temperature changes during the day and night and also varies from season to season. Its variation affects the land animals more than the aquatic animals where temperature changes are nominal Water: - It is the major part of protoplasm and maintains the turgidity of the cells. It acts as a solvent for the most of the metabolites. Inorganic substances enter the pants with water in dissolved form. It is the raw material for photosynthesis. SOIL: - Soil is the upper layer of earth’s crust. It consists of soil particles of varying size where microorganisms decompose the dead animals and plants to convert them into humus. Humus enriches the soil and increases its water and air holding capacity. Most of the plants are anchored in the soil and depend on it for their growth by absorbing water and inorganic substances. The type of soil and its fertility determine the flora hence, fauna of an ecosystem. AIR:- Air is a gaseous envelope which surrounds the earth. Air is a mixture of nitrogen, oxygen, carbon dioxides and water vapors. It plays an important role in the smooth running of an ecosystem. Nitrogen is an essential constituent of proteins. Oxygen is vital for respiration of all the living beings whereas carbon dioxide is a must for photosynthesis of carbohydrates. Biotic components of ecosystem The living organisms that interact in an ecosystem make up its biotic components. These living components include producers, all type of consumers, and the decomposers It can be further classified as: (i) Autotrophic component (ii) Heterotrophic component Further divided as: (a) Macroconsumers: herbivores, carnivores, omnivores (b) Microconsumers: bacteria, actinomycetes and fungi Autotrophs/Producers Autotrophs - use energy from the sun or energy stored in chemical compounds to prepare their own food. Producers are the primary source of energy for other organisms. Most producers capture sunlight to make carbohydrates (such as glucose) by photosynthesis. Heterotrophs/ Consumers Get their energy and nutrients by feeding on other organisms or their remains  I. Primary consumers (herbivores): Are those that eat producers (plants) as a source of food II. Secondary consumers (carnivores) :Eat other animals III. Tertiary Consumers : Large Carnivores which feed on secondary consumers IV. Quaternary Consumers: Largest Carnivores that feed on tertiary consumers. They are not eaten by any animals V. Omnivores: Have mixed diet that include both plants and animals. Decomposers and Scavengers Decomposers It includes both micro-decomposers and macro-decomposers. Decompose organic matter and return nutrients to soil, water, and air. Scavengers consume dead organisms. Eg. Bacteria, fungi and some protozoan. Food chain The transfer of food energy from the plants (producers) to a series of consumers with repeated eating and being eaten is called a food chain. Energy Flows through an Ecosystem in a Complex Network of Feeding relationships called a FOOD WEB. DEFINITION OF ENVIRONMENTAL BIOLOGY With the advancement in the knowledge of environment explosive increase in human population, scarcity of space, food problems, deterioration of hygienic conditions, threatening depletion of natural resources and socio economic problems, one need extensive and exhaustive study of environment , particular in relation to human survival and benefit The branch of science that seeks to determine the effects of environmental factors on the growth, distribution and migration of the organisms and also deals with other aspects of relationship between organisms is called Environmental biology. Environmental Biology is a multidisciplinary science which encompasses vastly different fields such as geography, climatology, pedology, microbiology, biochemistry, physiology, biophysics, biometry, sociology, economics etc. IMPORTANCE OF ENVIRONMENTAL BIOLOGY Conservation of Environment: Ecology helps us to understand how our actions affect the environment. It shows the individuals the extent of damage we cause to the environment. Lack of understanding of ecology has led to the degradation of land and the environment. It has also led to the extinction and endangerment of certain species. For eg., dinosaurs, white shark, mammoths, etc. Thus, the study of the environment and organisms helps us to protect them from any damage and danger. Resource Allocation: With the knowledge of ecology, we are able to know which resources are necessary for the survival of different organisms. Lack of ecological knowledge has led to scarcity and deprivation of these resources, leading to competition. Energy Conservation: All organisms require energy for their growth and development. Lack of ecological understanding leads to the over-exploitation of energy resources such as light, nutrition and radiation, leading to its depletion. Proper knowledge of ecological requirements prevents the unnecessary wastage of energy resources, thereby, conserving energy for future purposes. Eco-Friendliness: Ecology encourages harmonious living within the species and the adoption of a lifestyle that protects the ecology of life.