ENS195 Lesson 1 PDF

Organism – one individual living creature Population – subset of individuals of one species in a geographic area Community – group of populations of two or more different species Ecosystem – geographic area where all organisms interact with weather and landscape (biotic + abiotic factors) Biocoenos...

Organism – one individual living creature Population – subset of individuals of one species in a geographic area Community – group of populations of two or more different species Ecosystem – geographic area where all organisms interact with weather and landscape (biotic + abiotic factors) Biocoenosis – a community of interacting organisms living together in a specific habitat (biotope) – focuses on species interactions in specific habitat (e.g., a coral reef); Emphasizes mutual dependencies among organisms. Biotic community – all living organisms in a specific area, emphasizing their interactions – Emphasizes interactions like predation and competition biological community – similar to a biotic community, it refers to diverse populations of different species coexisting – emphasizes species diversity and complexity in an area (e.g. grasslands) ecological community Life assemblage – a group of organisms that lived together at the same time and place, often used in paleontology Interaction Type Definition Examples Sign Occurs when individuals or species vie for the same Two plant species competing for Competition - limited resources (e.g., food, sunlight in a forest. space). One organism (predator) hunts A hawk catching and eating a Predation and consumes another (prey), + (predator) / - (prey) mouse. benefiting the predator.  A specific form of predation A giraffe feeding on acacia + (herbivore) / - Herbivory where animals consume plants leaves. (plant) or plant parts. A close association between Clownfish living among sea two or more different biological anemones; the clownfish gets Mutualism +/+ Symbiosis species, which can be protection while the anemone Parasitism) +/- mutualistic, parasitic, or receives nutrients from Commensalism +/0 commensal. clownfish waste. Types of Symbiosis or Symbiotic Interactions One organism (the parasite) A tapeworm living in the intestines of a + (parasite) Parasitism benefits at the expense of mammal, absorbing nutrients while / - (host) another (the host). harming the host. One organism benefits while Barnacles attaching to a whale; Commensalis + (commensal) the other is neither helped nor barnacles gain mobility and access to m / 0 (host) harmed. food, while the whale is unaffected. Bees pollinating flowers while obtaining Both organisms benefit from Mutualism nectar; both species gain from this +/+ (both) the interaction. relationship. Abiotic factors – determine the type of organisms that can successfully live in a particular area Biotic factors – include the plants, animals, fungi, bacteria that live in an area – can be producers, consumers, and decomposers Components of Biotic Factors: Producers (Autotrophs) – Form the base of the food web – Organisms that produce their own food through photosynthesis or chemosynthesis. Consumers (Heterotrophs): – Organisms that cannot produce their own food – Depend on producers or other consumers for energy and nutrients. Types of Consumers: 1. Primary Consumers: Herbivores that eat plants (e.g., rabbits, deer). 2. Secondary Consumers: Carnivores that eat herbivores (e.g., snakes, birds of prey). 3. Tertiary Consumers: Carnivores that eat other carnivores (e.g., lions, hawks). Decomposers (Detritivores): – Organisms that break down dead organic material, recycling nutrients back into the ecosystem. Types of Ecosystem: 1. Aquatic Ecosystems: – These are ecosystems found in water bodies, divided into two main categories: freshwater (low salt content) and marine (saltwater) Ecosystems. a) Freshwater Ecosystems: Refers to water bodies that have low concentrations of dissolved salts (specifically, low salinity). 3 Types of Freshwater Ecosystems: Lentic: Standing or still or slow-moving waters like lakes and ponds. Lotic: Flowing waters like rivers and streams and exhibit longitudinal gradation or gradual change in temperature observed along the length of a water body Wetlands: Areas where water covers the soil, such as marshes and swamps, supporting unique plant and animal life. b) Marine Ecosystem: These are saltwater environments such as oceans, coral reefs, and estuaries. Marine ecosystems cover a large portion of the Earth and support a wide variety of life. 2. Terrestrial Ecosystems: These ecosystems are found on land, and are categorized into: Forest, Grassland, Mountain, and Desert ecosystems. a) Forest Ecosystems: Dense areas with a wide variety of trees, plants, and animals. Examples include tropical rainforests and temperate forests. b) Grassland Ecosystems: Dominated by grasses rather than large trees. Examples include savannas and prairies. c) Mountain Ecosystem: Found in mountainous regions with diverse climates and vegetation depending on altitude.  d) Desert Ecosystems: Dry regions with sparse vegetation and extreme temperatures. Examples include hot deserts like the Sahara and cold deserts like the Gobi. Terrestrial biome – an area of land with a similar climate that includes similar communities of plants and animals Summary of Marine Ecosystem Zones: Estuaries: Where freshwater meets saltwater, highly productive areas. Salt Marshes: Coastal wetlands that provide critical wildlife habitats. Mangrove Forests: Coastal forests that protect shorelines and house diverse life. Coral Reefs: Biodiversity-rich underwater ecosystems. Open Ocean: The vast, nutrient-poor areas of the ocean, home to large marine species. Deep-Sea Ocean: The dark, cold abyss that harbors unique, specially adapted organisms. Summary of Terrestrial Ecosystems: Desert: Dry, extreme environments with sparse vegetation and animals adapted to water scarcity. (amount of rainfall ⎯ less than 25 centimeters of rain per year_ Forest: Dense tree cover with high biodiversity, varying by climate (tropical, temperate, and boreal/taiga). (primary plant in this ecosystem is trees) Grassland: Dominated by grasses, with few trees, and home to large herbivores. Taiga (Boreal Forest): Cold, coniferous forests, with long winters and short summers. Tundra: Cold, treeless areas with permafrost, limited plant growth, and unique animal adaptations. Two types of tundra exist: arctic and alpine. Arctic tundra – located in the Arctic Circle, north of the boreal forests. Alpine tundras – occur on mountain tops. Types of Forests: 1. Temperate Deciduous Forest: Found in North America, Europe, and parts of Asia. Experiences four distinct seasons. Rich soil due to leaf litter decomposition. 2. Temperate Rainforest: Located in coastal regions with heavy rainfall. Supports a diverse range of flora and fauna. Often has a thick understory of ferns and shrubs.  3. Tropical Rainforest: Located near the equator (e.g., Amazon Basin, Congo Basin). High levels of biodiversity with many endemic species. Poor soil quality due to rapid decomposition and nutrient uptake. 4. Tropical Dry Forest: Found in regions with seasonal rainfall patterns. Trees lose leaves during the dry season to conserve water. Supports various wildlife adapted to seasonal changes. 5. Northern Coniferous Forests (Taiga): Extends across Canada, Alaska, Russia, and northern Europe. Dominated by conifers that can withstand cold temperatures. Important for carbon storage but has lower biodiversity. Biosphere – Made up of the parts of Earth where life exists (all ecosystems) Biogeochemical cycles – Pathway by which a chemical substance is turned over or moves through the biotic and the abiotic compartments of Earth. Element Interactions in Natural Cycles: Carbon Cycle: Primarily involves carbon, but is influenced by nitrogen (for plant growth), phosphorus (for productivity), water (as a medium for carbon transport and storage), and sulfur (through atmospheric interactions). Nitrogen Cycle: Primarily involves nitrogen, but is influenced by carbon (through organic matter decomposition), phosphorus (through plant productivity), water (as a solvent and transport medium), and sulfur (influencing soil and atmospheric processes). Process Definition: Carbon cycle – primarily involves carbon for energy storage; regulation of CO₂ in the atmosphere, and carbon storage in sinks like forests and oceans. Nitrogen cycle – primarily involves nitrogen for nitrogen fixation for plant uptake, and cycling of nitrogen back to the atmosphere through biological processes. Albedo (Reflectivity): – The ability of surfaces to reflect solar energy is called albedo. Higher albedo means more reflection. Greenhouse effect — natural process where certain gases in the atmosphere trap heat, keeping the Earth warm enough to support life (e.g. human activities, such as burning fossil fuels, are increasing CO2 levels in the atmosphere, enhancing the greenhouse effect and contributing to global warming) The Greenhouse Effect Key Processes: 1. Reflection and Absorption: – About 30% of incoming solar radiation is reflected back into space. – The remaining 70% is absorbed by Earth's surface and atmosphere, warming the planet. 2. Heat Retention: – Absorbed energy heats the Earth's surface, which then radiates heat back into the atmosphere as infrared radiation. – Greenhouse gases absorb some of this heat and re-radiate it, keeping the atmosphere warm. Energy and the Greenhouse Effect Numbers: – Of the solar energy that reaches the outer atmosphere: About one-quarter (¼) is reflected by clouds and the atmosphere. Another quarter (¼) is absorbed by carbon dioxide water vapor, ozone and a few other gases. About half (½) reaches the earth’s surface. Photosynthesis – influenced by light intensity, temperature, and availability of water Decomposition – reverse of photosynthesis, organic matter converted into inorganic compounds and organisms Herbivory – eating of plants by animals of various types Carnivory – the eating of animals by other animals Ectotherms – "cold-blooded" animals; rely on external environmental conditions to regulate their body temperature Endotherms – "warm-blooded" animals; generate and maintain their body heat internally through metabolic processes Hibernation - winter dormancy Estivation - summer dormancy Fire cycle – natural process where fires clear old vegetation, recycle nutrients into the soil, and help new plants grow Some species depend on fire to reproduce or thrive. After a fire, the ecosystem gradually recovers through plant and animal regrowth. Regular fires prevent dangerous buildup of dry vegetation and help maintain a healthy balance in ecosystems. Controlled burns can also be used to manage fire-prone areas and prevent larger, more destructive fires. Example: Lodgepole pine cones are tightly closed with resin. When exposed to fire, the heat melts the resin, allowing the cones to open and release seeds. This process enables the seeds to germinate in nutrient-rich soil created by the fire, helping the trees regenerate after disturbances. 4 Factors that influence the distribution of plants and animals 1. Temperature 2. Water 3. Light 4. Fire Food Chain vs. Food Web Aspect Food Chain Food Web  A linear sequence showing how energy A complex network of interconnected Definition and nutrients flow from one organism to food chains illustrating the feeding another in an ecosystem. relationships among species. Simple, with a single pathway of energy Complex, with multiple pathways and Structure flow (e.g., Plant → Herbivore → interactions (e.g., many plants feeding Carnivore). various herbivores). Typically consists of a few trophic levels Includes multiple trophic levels with Trophic (producers, primary consumers, various producers, consumers, and Levels secondary consumers). decomposers interconnected. Grass → Rabbit → Fox; Grass → Deer → Example Grass → Rabbit → Fox Lion; Phytoplankton → Zooplankton → Fish Grazing Food Chain vs. Detritus Food Chain Aspect Grazing Food Chain Detritus Food Chain Definition A type of food chain where energy flows from A type of food chain that begins with autotrophic plants (producers) to herbivores dead organic matter and involves  (primary consumers) and then to carnivores detritivores that break down this (secondary consumers). matter. Energy comes from decomposing Energy Energy is derived directly from sunlight organic matter (detritus) and is Source through photosynthesis by producers. utilized by detritivores. Usually smaller in scale, involving Trophic Typically includes several levels: producers → detritivores feeding on dead matter, Levels herbivores → carnivores. followed by predators of detritivores. Role in Important for recycling nutrients Helps in adding energy to the ecosystem and Ecosyste back into the ecosystem and supports a diverse range of organisms. m maintaining soil fertility. Grass → Rabbit → Fox; Phytoplankton → Dead leaves → Earthworms → Small Examples Zooplankton → Fish birds