Envi Sci Lecture 2 Ecological Concepts PDF

Environmental Science Ecological Concepts Lecture 2 Ecological Hierarchy Levels of Organization in Ecology Ecology science that deals with the study of interactions between organisms and their environment this study can take place at several different levels, from the broad eco...

Environmental Science Ecological Concepts Lecture 2 Ecological Hierarchy Levels of Organization in Ecology Ecology science that deals with the study of interactions between organisms and their environment this study can take place at several different levels, from the broad ecosystem level through community interactions to population studies and the study of the niche of individual organisms also involves study of the physical environment and the atoms and molecules that make up both the living and nonliving parts of an ecosystem Individual basic unit in ecology - senses and responds to the prevailing physical environment both respond to and influence the abiotic environment Population group of individuals of the same species that occupy a given area do not function independently of one another two populations may mutually benefit each other, each doing better in the presence of the other. Population Some populations compete with other populations for limited resources, such as food, water, or space in other cases, one population is the food resource for another. Community all populations of different species living and interacting within an ecosystem the primary focus is on factors influencing the relative abundances of various species coexisting Ecosystem the collective properties characterizing the flow of energy and nutrients through the combined physical and biological system Landscape* a patchwork of ecosystems whose boundaries are defined by distinctive changes in the underlying physical environment or species composition Biosphere linkages between ecosystems and other components of the earth system, such as the atmosphere Barry Commoner Barry Commoner A renowned biologist and environmental activist. He introduced his four laws of ecology in the 1970s. These laws emerged during a time of growing public concern about environmental issues, such as pollution, resource depletion, and climate change. Stahp Commoner’s Laws/ Four laws of Ecology Everything Is Connected to Everything Else Everything Must go Somewhere Nature Knows Best There Is No Such Thing as a Free Lunch Everything Is Connected to Everything Else “when we try to pick out anything by itself, we find it hitched to everything else in the universe” John Muir American naturalist, author, & environmental philosopher Everything Is Connected to Everything Else This law highlights the interconnectedness of ecosystems. Actions in one part of the world can have unintended consequences in another. For example: deforestation in the Amazon rainforest changes in global weather patterns affecting agriculture and water resources in distant regions. Everything Is Connected to Everything Else Implications Interdependence No part of an ecosystem exists in isolation. Changes to one component can have cascading effects on others. Holistic Approach Environmental problems cannot be solved in isolation. Solutions must address the entire ecosystem. Food Chains & Food Webs The first law of ecology can be observed in a more ecological perspective through food chains & food webs. Food Chains Depicts a single pathway of energy flow from one organism to another. Food Webs Shows multiple interconnected food chains, illustrating the various feeding relationships among organisms. Food Chains & Food Webs Trophic Levels The feeding positions in a food chain or web are called trophic levels Two types of organisms: Autotrophs producers (can make their own food) Hetertrophs consumers (prey on other organisms) Food Chains & Food Webs Trophic Levels The feeding positions in a food chain or web are called trophic levels Producer The first trophic level, producers are organisms that can create their own food through photosynthesis or chemosynthesis. Examples include plants, algae, and some bacteria. Food Chains & Food Webs Trophic Levels The feeding positions in a food chain or web are called trophic levels Primary Consumer These organisms consume producers directly. Examples include herbivores like deer, rabbits, and insects. Food Chains & Food Webs Trophic Levels The feeding positions in a food chain or web are called trophic levels Secondary Consumer These organisms consume primary consumers. Examples include carnivores like foxes, snakes, and birds of prey. Food Chains & Food Webs Trophic Levels The feeding positions in a food chain or web are called trophic levels Tertiary Consumer These organisms consume secondary consumers. Examples include apex predators like lions, sharks, and eagles. Food Chains & Food Webs Trophic Levels The feeding positions in a food chain or web are called trophic levels Quaternary Consumer These are the top predators in a food chain, and they consume tertiary consumers. However, not all food chains have this level. Food Chains & Food Webs Decomposers break down dead organisms and waste products, returning nutrients to the organic matter in the environment. their role is more circular and interconnected than the linear progression of a food chain. Food Chains & Food Webs Types of Food Chains (Smith & Smith 2009): Grazing food chain beginning with autotrophs Detrital food chain beginning with dead organic matter Food Web A food web is a complex diagram that shows the feeding relationships between organisms in an ecosystem. It's like a network of interconnected food chains, illustrating how energy flows from one organism to another. Species Interactions Interactions between different organisms within an ecosystem. These relationships can be beneficial (positive +), harmful (negative -), or neutral (0) to the organisms involved. Species Interactions Mutualism (+/+) Both organisms benefit from the interaction. For example, bees pollinate flowers in exchange for nectar. Species Interactions Competition (-/-) Organisms compete for resources such as food, water, and shelter. For example, lions and hyenas may compete for the same prey. Species Interactions Parasitism (+/-) One organism (parasite) lives on or inside another organism (host) and benefits at the host's expense. For example, tapeworm parasitize mammals. COOK YOUR BEEF Taenia saginata, or beef tapeworm, is parasitic and infects human hosts through consumption of raw or undercooked beef. Cysts present on raw or undercooked beef can survive gastric acid and release larvae inro the small intestine where it can live for up to 30-40 years (that’s why it can grow so long) if left untreated. Species Interactions Difference between parasitism and predation is that predation causes instantaneous harm/death of the prey while parasitism, requires the continued survival of the host. Predation (+/-) One organism (predator) hunts and consumes another organism (prey). For example, a cheetah hunts a gazelle Species Interactions Commensalism (+/0) One organism benefits, while the other is neither harmed nor benefited. For example, remora fish attach to sharks for protection and transportation. Species Interactions Ammensalism (-/0) One organism is harmed, while the other is neither harmed nor benefited. For example, interaction between Penicillium produces penicillin which eradicates growth of Staphylococcus (causes abscesses/cellulites, etc.) Everything must go Somewhere Everything must go somewhere This law addresses the concept of waste and pollution. There is no "away" when it comes to waste; it must be transformed or recycled in some way. Industrial waste, for example, can pollute water and air, harming ecosystems and human health. Life Support Cycles In an ecosystem there is only a finite number of resources such as minerals, water, soil, and air. These resources must be renewed through a cycle to sustain life on earth. The most important cycles in an ecosystem are as follows: Carbon dioxide-Oxygen Cycle Water Cycle Nutrient Cycle Carbon Dioxide-Oxygen Cycle Photosynthesis: The Oxygen Producers Plants and algae utilize sunlight, water, and carbon dioxide to produce their own food through photosynthesis. As a byproduct of photosynthesis they release oxygen into the atmosphere. Carbon Dioxide-Oxygen Cycle Respiration: The Oxygen Consumers Animals, plants, and other microorganisms take in oxygen from the atmosphere to break down food and release energy through aerobic cellular respiration. This process produces the byproducts carbon dioxide and water, which is exhaled into the atmosphere. Carbon Dioxide-Oxygen Cycle Decomposition: Returning Carbon to the Cycle Decomposers break down dead organic matter, releasing carbon dioxide back into the atmosphere. Carbon Dioxide-Oxygen Cycle Fossil Fuel Combustion: A Human Impact Humans burn fossil fuels (coal, oil, and natural gas), which are stored carbon from preserved ancient organisms. This activity releases large amounts of carbon dioxide into the atmosphere, contributing to climate change. Carbon Dioxide-Oxygen Cycle Ocean Absorption: A Natural Carbon Sink The oceans absorb a significant portion of the carbon dioxide emitted into the atmosphere. This helps to regulate the concentration of carbon dioxide in the air. As oceans absorb more carbon dioxide, oceans become more acidic, affecting organisms that inhabit the body of water. Photosynthesis Equation The reactants, six carbon dioxide molecules and six water molecules, are converted by light energy captured by chlorophyll (implied by the arrow) into a sugar molecule and six oxygen molecules, the products. Aerobic Respiration Equation Aerobic respiration is made of four stages: glycolysis, the link reaction, the Krebs cycle and oxidative phosphorylation. During aerobic respiration, glucose is effectively burned inside our bodies (it reacts with oxygen) to produce carbon dioxide, water and lots of energy in the form of ATP. Carbohydrate plus oxygen forms carbon dioxide plus water. Water Cycle. Evaporation: From Liquid to Gas The sun heats up bodies of water (oceans, lakes, rivers) and land. This heat causes the water to evaporate, turning it into water vapor. The water vapor rises into the atmosphere. Water Cycle Transpiration: Water from Plants Plants absorb water through their roots. Some of this water is released into the atmosphere through tiny pores in their leaves, a process called transpiration. This adds to the overall amount of water vapor in the atmosphere. Water Cycle Condensation: From Vapor to Liquid As the water vapor rises, it cools. When the vapor cools enough, it condenses into tiny water droplets or ice crystals, forming clouds. Water Cycle Precipitation: Falling Water When the clouds become saturated with water droplets or ice crystals, they can no longer hold all the water. The water falls back to the Earth's surface as precipitation (rain, snow, or hail). Water Cycle Surface Runoff: Water Flow Precipitation that falls on land can flow over the surface, collecting in streams, rivers, and lakes. Eventually, this surface runoff can make its way back to the ocean. Water Cycle Surface Runoff: Water Flow Precipitation that falls on land can flow over the surface, collecting in streams, rivers, and lakes. Eventually, this surface runoff can make its way back to the ocean. Water Cycle Infiltration: Water into the Ground Some of the precipitation that falls on land can infiltrate the soil. This infiltrated water becomes groundwater, which can be stored in underground aquifers. Groundwater can flow through aquifers, eventually returning to rivers, lakes, or the ocean. Nutrient Cycle Nutrient Uptake: From Soil to Organisms Plants absorb nutrients from the soil through their roots. Animals obtain nutrients by consuming plants or other animals. Nutrient Cycle. Nutrient Assimilation: Building Blocks of Life Organisms use the absorbed nutrients to build tissues, organs, and other body parts. Nutrient Cycle. Nutrient Release: From Organisms to Environment Organisms release nutrients through waste products (e.g., urine, feces). When organisms die, decomposers (bacteria and fungi) break down their remains, releasing nutrients back into the environment. Nutrient Cycle Nutrient Cycling: Through Soil and Water Nutrients can be stored in the soil and released slowly over time. Nutrients can be transported through water bodies (e.g., rivers, lakes, oceans) and eventually return to the land. Nutrient Cycle Nutrient Fixation: Atmospheric Nitrogen to Soil Some bacteria can convert atmospheric nitrogen into a form that plants can use. This process helps to enrich the soil with nitrogen, a crucial nutrient. Nutrient Cycle Nutrient Fixation: Atmospheric Nitrogen to Soil Nitrogen-fixing bacteria: Some bacteria can convert atmospheric nitrogen into a form that plants can use. Soil enrichment: This process helps to enrich the soil with nitrogen, a crucial nutrient. Energy Flow Energy flow in an ecosystem refers to the movement of energy from one organism to another. It's a one-way process, meaning energy cannot be recycled or reused. Everything is Always Changing Nature knows best Ecological Succession The gradual process of change in a community of organisms over time. It involves the replacement of one group of species by another, leading to a more complex and stable ecosystem. There are two types of ecological succession: Primary Secondary Primary Succession The ecological process that begins in areas where there is no existing soil or vegetation. It's often associated with harsh environments like volcanic islands, glacial moraines, or newly exposed rock surfaces. Primary Succession Primary succession occurs in areas where there is no existing soil or vegetation, such as after a volcanic eruption or glacial retreat. The first organisms to colonize these areas are called pioneer species, often lichens and mosses. Over time, these pioneer species help to form soil by breaking down rocks and organic matter. As the soil develops, other plants and animals begin to colonize the area, leading to a series of succession stages. Primary Succession Intermediate species They play a crucial role in the process of ecological succession, which is the gradual change in a community of organisms over time. These species often serve as keystone species that help to shape the ecosystem and facilitate the transition from one stage of succession to the next. Primary Succession Climax Community A climax community is the final stage of ecological succession, where an ecosystem has reached a relatively stable and self-sustaining state. It represents the most mature and complex stage of community development in a particular environment. Secondary Succession Secondary succession occurs in areas where an existing community has been disturbed, such as after a fire, flood, or deforestation. The remaining organisms and seeds in the soil can quickly begin to regrow, leading to a more rapid recovery process than primary succession. Secondary Succession Disturbance A disturbance event, such as a natural disaster or human activity, initiates secondary succession. Secondary Succession Regeneration Existing plants and seeds in the soil can quickly begin to regrow, leading to a more rapid recovery process than primary succession. Secondary Succession Pioneer species While pioneer species like lichens and mosses might still play a role in early stages, the process is generally faster due to the presence of existing soil and organic matter. Secondary Succession Successional stages The stages of secondary succession are similar to primary succession, but they occur more rapidly and with a different initial starting point. Secondary Succession Climax community The final stage of secondary succession is also a climax community, which is a stable and mature ecosystem. Adaptation The process by which organisms evolve to become better suited to their environment. It involves changes in physical features, internal processes, or behaviors that help an organism survive and reproduce in its specific habitat. There are generally three types of adaptation: Structural Physiological Behavioral Structural These are alterations to an organism's body that help it survive. Example: Camouflage in chameleons, fins in fish, and the thick fur of polar bears. Physiological These are adjustments to an organism's internal processes. Example: the ability of plants to photosynthesize, and the production of venom by snakes. Behavioral Changes in behavior: These are alterations in how an organism acts to survive. Example: Migration of birds, tool use by apes, hibernation and aestivation* (can be classified as physiological as well). Estivation vs Hibernation Aestivation and hibernation are both states of reduced metabolic activity that organisms enter to conserve energy during periods of environmental stress. Estivation (summer sleep) Triggered by heat and dryness (summer) Conserve energy and water Adaptations include: Thick skin, waxy cuticle, or ability to store large volumes of water. Estivation vs Hibernation Aestivation and hibernation are both states of reduced metabolic activity that organisms enter to conserve energy during periods of environmental stress. Hibernation (winter sleep) Triggered by cold temperatures. Conserve energy due to lack of food or extreme cold. Adaptations include thick fur or layers of fat. There is no such thing as a free Lunch There is no such thing as a free Lunch Applicable in almost everything (ecology, economy, sociology, etc.) Everything costs something. All we eat, wear, and use during our lives involve environmental costs. These costs can include: contaminated water supplies loss of wildlife habitat soil erosion air pollution loss of animal and plant species depletion of the ozone layer acid rain waste disposal There is no such thing as a free Lunch Food to Consumer: Toasted Sesame Seed Bun the farmer prepares the ground → plants wheat seed → cares for the crop until ready for harvest → harvested grain is refined → flour is sold to bun factory → buns are baked then shipped to restaurant There is no such thing as a free Lunch Food to Consumer: What are some of the costs to ourselves, others, and the natural environment? There is no such thing as a free Lunch Costs: Chemical resistance of insects and weeds due to constant exposure Chemical overuse may runoff and seep contaminating the groundwater Collateral damage - larger doses of chemicals may kill other organisms that the farmer does not necessarily want to kill Fertilizer overuse may runoff in bodies of water, - algal blooms - depleted Oxygen levels for aquatic life Over-exposure of farmers to chemicals - may cause temporary illnesses or permanent disabilities Enormous energy costs - machinery, transportation, and equipment There is no such thing as a free Lunch Costs: Chemical resistance of insects and weeds due to constant exposure Chemical overuse may runoff and seep contaminating the groundwater Collateral damage - larger doses of chemicals may kill other organisms that the farmer does not necessarily want to kill Fertilizer overuse may runoff in bodies of water, - algal blooms - depleted Oxygen levels for aquatic life Over-exposure of farmers to chemicals - may cause temporary illnesses or permanent disabilities Enormous energy costs - machinery, transportation, and equipment Limiting Factors Limiting Factors Environmental conditions that restrict the growth or distribution of a population. These factors can be biotic (living) or abiotic (non-living). Abiotic Limiting Factors: Temperature Water Availability Sunlight Nutrients Oxygen Salinity Biotic Limiting Factors: Predation Competition Disease Parasitism Significance of Limiting Factors The specific limiting factors that affect a population can vary depending on the species and its environment. Understanding limiting factors is important for understanding population dynamics and for conservation efforts. Significance of Limiting Factors Ecological Niches Ecological Niches The interrelationship of a species with all the biotic and abiotic factors affecting it. Describes the relational position of an organism or a population in a particular ecosystem. Ecological Niches Dung beetles engage in an activity called coprophagy (eating poop). Allows the species to access important nutrients that have passed through the guts of mammals. Dung beetles are flightless insects that are said to be “picky eaters”. The dung beetle prefers nitrogen rich organic matter. Things to consider the physical space a species occupies the temperature conditions of the space the moisture conditions of the space the seasonality in abiotic and biotic conditions that the space experiences food/dietary requirements reproduction requirements the interactions that a species engages in with other species Types of Niches Fundamental Niche Represents the full range of environmental conditions and resources a species could potentially occupy in the absence of competition. Realized Niche The portion of the fundamental niche a species actually occupies in a given environment. Takes in consideration the presence of competition and/or predation. Example: A squirrel's fundamental niche might include a variety of habitats, such as forests, parks, and suburban areas. However, due to competition with other species or human activities, its realized niche might be limited to a specific type of forest or a particular neighborhood. Types of Niches Overlapping Niches Multiple organisms compete for the same resources, such as food, water, and shelter, in a given habitat. Overlapping niches can lead to competition, which may result in: Competitive Exclusion principle in ecology that states that two species cannot occupy the exact same niche in the same habitat for long. Eventually, one species will outcompete the other, leading to the exclusion of the less competitive species. Overlapping Niches Multiple organisms compete for the same resources, such as food, water, and shelter, in a given habitat. Overlapping niches can lead to competition, which may result in: Niche Partitioning A process where species that occupy similar niches evolve to specialize in different aspects of that niche, reducing competition and allowing them to coexist. Spatial partitioning Species may use different parts of the habitat or different times of day. Dietary partitioning Species may specialize in consuming different types of food or different parts of the same food. Temporal partitioning Species may use the same resources but at different times. Spatial Partitioning Species may use different parts/regions of the habitat or different times of day. Different species of warbler occupy different regions/parts of the same tree. Dietary Partitioning Species may specialize in consuming different types of food or different parts of the same food. During migration: Zebras devour tall grass (worst quality) Wildebeest eat the leftovers of the zebras Thomson gazelle eat the newly grown grass (Greatest quality) Dietary Partitioning Temporal Partitioning Species may use the same resources but at different times. Owls and Eagles are considered apex predators and generally hunt for the same resource. However, they do so at different times as Owls are nocturnal (active during night) while Eagles are diurnal (active during day)