Ecology Why study ecology? What is ecology? Ecologists study the biosphere. The study of the interactions among living things, and between living things and their surroundings Organisms live within the biosphere! The regions of the surface and atmosphere of the Sooccupied why doby earth living organisms. ecologists study the biosphere? – Atmosphere = air – Lithosphere = ground – Hydrosphere = water Because all organisms must share the biosphere and ecologists must understand how they interact individually and collectively Ecologists use particular levels of organization. Biome Ecosystem Community Population Organism Biomes A biome is a major regional or global community of organisms. Biomes are characterized by the climate conditions and plant communities that thrive there. Tropical rain forest biomes produce lush forests. – warm temperature – abundant precipitation all year Source: World Meteorological Organization Grassland biomes are where the primary plant life is grass. Rapid City, South Dakota Source: National Oceanic Atmospheric Administration • Grassland biomes are where the primary plant life is grass. – Temperate grasslands are dry and warm during the summer; most precipitation falls as snow. – Tropical grasslands are warm through the year, with definite dry and rainy seasons. Desert biomes are characterized by a very arid climate. – very low amount of precipitation – four types: hot, semiarid, coastal, and cold Tucson, Arizona Source: National Oceanic Atmospheric Administration Temperate forest biomes include deciduous forests and rain forests. – Temperate deciduous forests have hot summers and cold winters. – Average precipitation – Deciduous trees are the dominant plant species. Burlington, Vermont Source: National Oceanic Atmospheric Administration • Temperate forest biomes include deciduous forests and rain forests. – Temperate deciduous forests have hot summers and cold winters. – Deciduous trees are the dominant plant species. – The temperate rain forests have a long wet season and relatively dry summer. – Ferns and moss cover the forest floor. The taiga biome is located in cooler northern climates. – boreal forest – long winters and short summers – small amount of precipitation Banff, Canada Source: Environment Canada The tundra biome is found in the far northern latitudes with long winters. – winter lasts 10 months – limited precipitation – permafrost Barrow, Alaska Source: National Oceanic Atmospheric Administration Minor biomes, such as chaparral, occur globally on a smaller scale. Polar ice caps and mountains are not considered biomes. Polar ice caps have no soil, therefore no plant community. The climate and organisms found on mountains change as the elevation changes. Biomes are made up of smaller units called ecosystems. An ecosystem includes all the organisms as well as the climate, soil, water, rocks, and other nonliving things in a given area Ecosystems may be large or small. Ecosystems are very complex! – They can contain hundreds or even thousands of interacting species. Within an ecosystem, there are living and nonliving components. Each organism depends in some way on other living and nonliving factors in its environment Living components are referred to as Biotic factors. Nonliving components are referred to as Abiotic factors. Biotic Factors Abiotic Factors Community A community is a group of different species that live together in one area Population A population is a group of the same species the lives in one area Organism An organism is an individual living thing Wrap Up: Ecologists study levels! Biome Ecosystem Ecosystem Community Community Population Population Organism Organism Energy in Ecosystems We talked about biotic and abiotic factors. What else is an important part of an ecosystem? – Energy Flow Energy is needed to fuel life processes, such as breathing and growing. Where does this energy come from? All organisms must have a source of energy in order to survive NOT all organisms obtain their energy by eating other organisms The simplest way to look at energy flow in an ecosystem is through a food chain. A food chain is a sequence that links species by their feeding relationships. – Shows connection between ONE producer and a single chain of consumers within an ecosystem There are different ways organisms obtain energy. Producers Organisms that get their energy from nonliving resources – They make their own food Producers are also called autotrophs All ecosystems depend on producers. Why? Not all producers depend on sunlight for their energy. Remember chemosynthesis? – Process by which organisms form carbohydrates using chemicals, rather than light, as an energy source Consumers Organisms that get their energy by eating other living or once-living resources such as plants and animals Consumers are also called heterotrophs Types of Consumers Herbivores Carnivores Omnivores Detritivores Decomposers Herbivores Organisms who eat only plants (eat only producers) Carnivores Organisms who eat only animals Omnivores Organisms animals who eat both plants and Detritivores Organisms that eat detritus, or dead organic matter Decomposers Organisms that break down organic material into simpler compounds Specialists and Generalists Specialists are consumers who primarily eat one specific organism Example: Florida Snail Kite Generalists are consumers who have a varying diet Example: Gray Wolf Trophic Levels Trophic levels are the levels of nourishment in a food chain. Food Webs Because generalists have a varying diet, they may be part of several food chains A food web is a model that shows the complex network of feeding relationships and the flow of energy within an ecosystem Remember our food web activity? Food Web Energy Pyramid An energy pyramid is a diagram that compares energy used by producers, primary consumers, and other trophic levels Create an energy pyramid You and your table mate will create an energy pyramid using the provided organisms. Step 1: Color organisms Step 2: Cut out organisms. Step 3: Arrange organisms on appropriate pyramid step Step 4: Calculate kilocalories per step Cycling of Matter in Ecosystems Matter changes form but it does NOT disappear – What happens if you crush a rock? Certain chemicals constantly cycle through the environment Biogeochemical Cycles A biogeochemical cycle is the movement of a particular chemical through the biological and geological, or living and nonliving, parts of an ecosystem Hydrologic Cycle precipitation condensation transpiration surface runoff groundwater evaporation water storage in ocean Aka the water cycle The circular pathway of water on Earth from the atmosphere to the surface, below the ground, and back. Oxygen Cycle Plants release oxygen as a waste product during photosynthesis Humans and other organisms take in O2 and expel CO2 Plants absorb CO2 for photosynthesis The Carbon Cycle carbon dioxide in air combustion respiration photosynthesis respiration decomposition of organisms fossil fuels photosynthesis carbon dioxide dissolved in water Photosynthesis and respiration account for much of the transformation and movement of carbon. Nitrogen Cycle aka Nitrogen Fixation Certain types of bacteria convert gaseous nitrogen into ammonia (NH3) Much of the N cycle occurs underground where bacteria transform nitrates into, which are used by plants to make amino acids. Create a Biogeochemical Foldable You and your table mate will create an informative biogeochemical foldable describing one of the four cycles previously discussed. You must include descriptive sentences and an illustration of the cycle. Interactions in Ecosystems To understand what individuals, populations, and communities need to survive, ecologist study the interactions among species and between species and their environment Habitat and Niche A habitat can be described as all of the biotic and abiotic factors in an area where an organism lives. WHERE an organism lives An ecological niche is composed of all the physical, chemical, and biological factors a species needs to survive, stay healthy and reproduce. HOW an organism lives When two species use the same resources in the same way, competition occurs. The principle of competitive exclusion states that when two species are competing for the same resources, one species will be better suited to the niche, and the other species will be pushed into another niche or become extinct. Ecological equivalents Ecological equivalents are two species that occupy similar niches in geographically separate areas. Madagascar mantella frog South American poison dart frog Organisms interact as individuals and as populations. Competition and predation are two important ways organisms interact. Competition occurs when two organisms fight for the same limited resource. Two types of competition: Intraspecific competition – organisms of the same species compete Interspecific competition – organisms of different species compete Predation occurs when one organism captures and eats another. Symbiosis Symbiosis is a close ecological relationship between two or more organisms of different species that live in direct contact with one another. There are three major types of symbiotic relationships. 1. Mutualism 2. Commensalism 3. Parasitism Mutualism: both organisms benefit Commensalism: one organism benefits, the other is unharmed Ø Human Our eyelashes are home to tiny mites that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle. Commensalism Ø Organism is not affected + + Organism benefits Demodicids Eyelash mites find all they need to survive in the tiny follicles of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. Parasitism: one organism benefits, the other is harmed + Parasitism + _ Hornworm caterpillar The host hornworm will eventually die as its organs are consumed by wasp larvae. _ Organism is not affected + Braconid wasp Braconid larvae feed on their host and release themselves shortly before reaching the pupae stage of development. Organism benefits Each population has a density and a dispersion. Population density is the number of individuals that live in a defined area. Population density is a measurement of the number of individuals living in a defined space. Scientists can calculate population density. Dispersion of a population shows how individuals in a population are spaced. Population dispersion refers to how a population is spread in an area. There are three types of dispersion. 1. Clumped Clumped dispersion 2. Uniform Uniform dispersion 3. Random Random dispersion Populations grow in predictable patterns. Changes in a population’s size are determined by: Immigration – movement of individuals into a population form another population Births – new offspring Emigration – movement of individuals out of a population and into another population Deaths – death of an individual Population growth is based on available resources. Exponential growth is a rapid population increase due to an abundance of resources. Often referred to as the “J Curve” Logistic growth is due to a population facing limited resources. Often referred to as the “S Curve” Carrying capacity is the maximum number of individuals in a population that the environment can support. • A population crash is a dramatic decline in the size of a population over a short period of time. After an ecosystem experiences a devastating catastrophe, it begins to re-grow through a process called succession. Succession is the sequence of biotic changes the regenerate a damaged community or create a community in a previously uninhabited area. There are two types of succession. – Primary succession – Secondary succession Primary Succession Primary succession is the establishment and development of an ecosystem in an area that was previously uninhabited. The first organisms to live in a previously uninhabited area are called pioneer species. Steps of primary succession: 1. Exposed bare rock begins to crack and break into smaller pieces (because of wind, rain and ice) 2. Wind brings in lichen and moss spores. These organisms grow in the cracks and break the rock even more. When these organisms die, their remains mix with the rock to form a thin layer of soil. 3. With time, seeds are introduced by wind or birds. Small flowers and hardy shrubs grow. 4. The soil continues to grow thicker. Small trees take root, and different animals move into the area. 5. Different tree species take root and eventually replace the original trees. Secondary Succession Secondary succession is the reestablishment of a damaged ecosystem in an area where the soil was left intact. Plants and other organisms that remain start the process of regrowth. Time for a Scavenger Hunt!!!