Human Ecology By: Dechasa Adare (MSc.) Haramaya University 2023 Ac. year Dechasa.A dechasaadare@gmail.com 1 We are part of the environment along with all of Earth’s other organisms. Organization levels of biology Dechasa.A 2 Definition terms • Ecosystem: any geographic area that includes all of the organisms and nonliving parts of their physical environment • Biodiversity: Biological diversity is refers to the variety of life forms at all levels of organization Dechasa.A 3 Cont… • Biomes: a large, relatively distinct terrestrial region characterized by a similar climate, soil, plants, and Example: rainforest, grassland, desert animals regardless of where it occurs on earth • Ecosphere: The interrelation among and between living organisms and the atmosphere, lithosphere and hydrosphere that they occupy. Dechasa.A 4 Cont… Community—all the organisms living in a certain area. Example: pond community Population—all the organisms of the same species living in the same area. Example: frogs in a pond Dechasa.A 5 Cont… • Habitat—place where an organism lives. It provides food, water, shelter, and a place to reproduce. • Example: a woodpecker’s habitat is the trees in a forest. • Niche—everything an organism does and everything it needs in its habitat. • It is often defined as an organism’s job or role in its community. • Example: a woodpecker’s niche is catching and eating insects. Dechasa.A 6 Cont… • Limiting factor: An environmental factor that restricts the growth, distribution, or abundance on a particular population • Amount of water, food, and temperature • Tolerance: Decreased response to a specific factor in the environment over time • Ecological Succession: The process by which organisms occupy a site and gradually change environmental conditions so that other species can replace the original inhabitants. Dechasa.A 7 Definition, Scope and Relationship with other sciences • Ecology: branch of science that deals with interaction between living organisms with each other and their surroundings • Ecology is a multi-disciplinary science, drawing on many other branches of science Dechasa.A 8 Cont… • Ecological footprint: The amount of biologically productive land and water needed to indefinitely supply the people in a given area with renewable resources • Per capita ecological footprint: Average ecological footprint of an individual in a given area • Ecological deficit: Total ecological footprint greater than biological capacity for resource renewal and absorption of wastes and pollution Dechasa.A 9 Cont… Dechasa.A 10 Scope of Ecology • Ecology can be studied at several levels: • From proteins and nucleic acids (in biochemistry and molecular biology) • Cells (in cellular biology) • Organisms (in botany, zoology, and other similar disciplines) • At the level of populations, communities, and ecosystems Dechasa.A 11 Cont… Organismal ecology Population ecology Community ecology The focus of ecological studies occurs at many different scales. Ecosystem ecology Landscape ecology Global ecology Dechasa.A 12 Disciplines of ecology • Ecology is a broad science which can be subdivided into major and minor sub discipline. • The major sub-disciplines include: • Behavioral ecology, studies the ecological and evolutionary basis for animal behavior, and the roles of behavior in enabling animals to adapt to their ecological niches • Population ecology, deals with the dynamics of populations within species, and the interactions of these populations with environmental factors Dechasa.A 13 Cont… • Community ecology: studies the interactions between species within an ecological community; • Ecosystem ecology: studies the flows of energy and matter through ecosystems; • Global ecology: looks at ecological questions at the global level: macro ecological questions Dechasa.A 14 Broadly, ecology is divided into following categories • Physiological ecology: Study about the response of single species to environmental factors • Population ecology: focusing on the abundance and distribution of individual species and the factors that cause such distribution; • Community ecology,: number of species found at given location and their interactions • Ecosystems ecology: structure and function of the entire suite of microbes, plants, and animals, and their abiotic environment, and how the parts interact to generate the whole. • i.e: energy and nutrient flows of ecosystems. Dechasa.A 15 Importance of Ecology • Human economies are based on the exploitation and management of nature • Study of population dynamics (demography) of our own species, the food and fossil energy flowing through our society • All of us live in a natural or partly natural ecosystem • Humans appear to be changing aspects of the global environment in many ways Dechasa.A 16 Ecology: Factors Sustaining Life 1) Gravity 2) Flow of Energy Producers Consumers Trophic Levels 3) Cycling of Matter and Nutrients • Carbon, Nitrogen, Water, Phosphorus, (Sulfur) Cycles Dechasa.A 17 Gravity • Atmosphere and life on earth Energy Sources • All living things obtain and use energy and materials Energy source for the natural world = Sun or Solar Energy Dechasa.A 18 Various ways to obtain, acquire energy • Autotrophs: an organisms capture energy from sunlight or chemicals and convert it into forms useable to living cells = • Called Primary Producers • By photosynthesis (light) or Chemosynthesis (chemicals) • Use solar energy EX: Algae, plants, and some Microorganisms Dechasa.A 19 Cont… • Deep-sea ecosystems depend on primary producers that use chemical energy from inorganic molecules such as hydrogen sulfide. • Chemosynthesis: is the use of chemical energy to produce carbohydrates Dechasa.A 20 Cont… • Heterotrophs = Organisms that must acquire energy from other organisms Cannot make their own food Must eat/ingest to get their energy Called consumers Dechasa.A 21 Types of Consumers: Diet • Consumers are classified by the ways in which they acquire energy and nutrients 1. Carnivores kill and eat other animals, and include snakes, birds of prey, lions, etc. 2. Scavengers= animals that consume the carcasses of other animals that have been killed by predators or have died of other causes 3. Herbivores = obtain energy and nutrients by eating plant leaves, roots, seeds, or fruits Dechasa.A 22 Cont… • Omnivores: animals whose diets naturally include a variety of different foods that usually include both plants and animals • Decomposers =feed by chemically breaking down organic matter Dechasa.A 23 Energy Flow What happens to energy stored in body tissues when one organism eats another? How does energy flow through ecosystems? Dechasa.A 24 Cont… • Energy moves from the “eaten” to the “eater.” A food chain = a series of steps in which organisms transfer energy by eating and being eaten. • Food chains can vary in length. Dechasa.A 25 Cont… • Food Webs: • Feeding relationships much more complicated than a chain • Each path through a food web is a food chain. • Links all of the food chains in an ecosystem together Dechasa.A 26 Trophic Levels • Each step in a food chain or food web = a trophic level Dechasa.A 27 Trophic level Pyramid About 10% of available is passed up 10 Tertiary Consumer The rest is lost as Heat and Waste Secondary Consumer 100 1000 Primary Consumer Heterotrophs Herbivores Producers Autotrophs Uses the sun’s energy to make its own food- photosynthesis Dechasa.A 28 Ecological pyramids • Ecological pyramids show the relative amount of energy or matter contained within each trophic level in a given food chain or food web. • There are 3 different types of ecological pyramids: • Pyramids of energy • Pyramids of biomass • Pyramids of numbers Dechasa.A 29 Cont… 2. Biomass Pyramid: • Represents the amount of living organic matter at each trophic level. • Largest biomass is at the base of the pyramid. • Pyramid of biomass records the total dry organic matter of organisms at each trophic level in a given area of an ecosystem Dechasa.A 30 Cont… 3. Pyramid of Numbers: Shows the relative number of individual organisms at each trophic level. Dechasa.A 31 Ecosystem Goods and Services Dechasa.A 32 i Humans, Biodiversity and Ecosystems Development impacts ecosystem services Ecosystem services sustain development Dechasa.A 33 What are ecosystem services? • Benefits derived from ecosystems • Products of ecosystem processes • Strong positive link between ecosystem processes and biodiversity • Loss of biodiversity strongly linked to reduced ecosystem services • Threat to human well-being Dechasa.A 34 Cont… Ecosystem goods and services represent the benefits that humans derive from naturally functioning ecological systems Dechasa.A 35 • Types of Ecosystem Services 1. Regulating services – purification of air and water, • detoxification and decomposition of wastes, climate regulation, erosion control etc. 2. Provisioning services – provision of food, fuel, fiber, and freshwater 3. Supporting services – formation and preservation of soils, protection from ultraviolet rays, pollination of natural vegetation etc. 4. Cultural services – spiritual, esthetic, recreational Dechasa.A 36 Cont… Dechasa.A 37 Cont… Joint products of ecosystems Dechasa.A 38 Implications • The degradation of ecosystem services could grow significantly worse during the first half of this century and is a barrier to achieving the Millennium Development Goals • Reversing ecosystem degradation while meeting increasing demands for their services will involve significant changes in policies, practices, and institutions Dechasa.A 39 Why ecosystem accounts? • Information for tracking changes in ecosystems, such as degradation • Information for linking those changes to human activities and human well-being • Extends the scope of our information for analysis of impacts on the environment (and, thus, ultimately, on societies) • Information on ecosystem services and the trade-offs/co-benefits involved Dechasa.A 40 Ecosystem Services as Flows From Ecosystem Assets Individual & societal well-being Benefits Ecosystem services Human inputs (e.g. labour, produced assets) Ecosystem processes Ecosystem characteristics Intra-ecosystem flows Inter-ecosystem flows ECOSYSTEM ASSET Dechasa.A 41 Ecosystem goods and services Systemic Model Secure environmental vision and governance Assess & Value Ecosystem Goods & Services Decentralized plans Monitor results, develop and share knowledge Spatial plans Innovative Finance Mechanism s Medium Environmen Term tal Fiscal Expenditure Reform Framework Sector Plans Integrated EGS benefits feed into Sustainable Development & Poverty Reduction Strategies Dechasa.A Demystifying “environmental jargon” EGS in Development/ Poverty/ Disasters 42 Common Look at Biodiversity and Ecosystems Common Understanding Real Situation Wrong Correct • Human beings are part of biodiversity - they interact directly with all its elements at different geographical and temporal scales. • Ecosystems provide vital services for human needs and development. They are found in a state of dynamic equilibrium, to which development can cause severe damages. Dechasa.A 43 Ecosystem Based Solutions vs Manmade Solutions Ecosystem Based Solutions Man-Made Solutions -Cheaper than man-made -Costly and might involve infrastructures (water treatment recurring operational costs plant…) -Can alter the functions and -Preserves the functions and services services of ecosystems of ecosystems -Requires access to technology -Ecosystem management skills required Mainly Pro-active Approach Dechasa.A Mainly Responsive Approach 44 Governance and Vision Sound environmental vision and governance can favor sustainable results Governance Strengthen environmental governance Dechasa.A Environmental Vision Working with nature 45 Set Long Term Environmental Vision Building an inclusive long term development vision of EGS Green Constitutions & Legal Initiatives Constitutions which refer Directly to environmental rights National Priorities Clear reference to ecosystem/biodiversity objectives in long term development strategies Global environ. Policiescommitments integrative of Multilateral Environmental Agreements Limits of Economic Models “Society must urgently replace its defective economic compass so that:• It does not jeopardize human well-being and planetary health Dechasa.A 47 Integrative and EGS Inclusive Planning Decentralized Plans Spatial Plans Plan in terms of spatial layers Dechasa.A Sectors Plans Plan at lowest level possible Include green considerations 48 Greener Budgeting and Financial Planning Budgeting and Financial planning need to be environmentally inclusive Innovative Financial Mechanisms Environmenta l Fiscal Reform Environmental taxation/ Eliminating perverse subsidies Dechasa.A New EGS based revenues Medium Term Expenditure Framework EGS based strategic budgeting 49 Adaptive Management and Knowledge Consolidation Data Collection Monitoring and Evaluation Lessons Learned and Knowledge sharing Continuously adjust strategies and plans Dechasa.A Develop new EGS knowledge Awareness and Capacity Building Enhance awareness and capacities 50 Ecosystem-Based Management Focuses on key ecosystem processes and their responses to perturbations; • Integrates ecological, social, and economic goals and recognizes humans as key components of the ecosystem; • Defines management based on ecological boundaries rather than political ones • Addresses the complexity of natural processes and social systems by identifying and confronting uncertainty Dechasa.A 51 Cont… • Uses adaptive management where policies are used as experiments and are modified as information is gained; • Engages multiple stakeholders in a collaborative process to identify problems, • Understand the mechanisms of driving factors • Considers the interactions among ecosystems Dechasa.A 52 Cont… Systems Ecology • All ecosystems are open systems embedded in an environment • Ecosystems have many levels of organization and operate hierarchically • Mass, including biomass, and energy are conserved • The carbon based life on Earth has a characteristic basic biochemistry which all organisms share • No ecological entity exists in isolation but is connected to others. Dechasa.A 53 Cont… • Ecosystem processes are irreversible (law of thermodynamics in ecology). • Biological processes use captured energy (input) to move further from thermodynamic equilibrium • After the capture of energy, ecosystem growth and development is possible (physical structure or biomass, network, information) • An ecosystem receiving solar radiation will attempt to maximize ecoexergy storage or maximize power Dechasa.A 54 Thank you By: Dechasa Adare (MSc.) Haramaya University 2023 Ac. year dechasaadare@gmail.com Dechasa.A 55
