Ecosystems PDF

ECOLOGY, ECOSYSTEM and ENVIRONMENT THE NATURE OF ECOLOGY Ecology is a study of connections in nature. How organisms interact with one another and with their nonliving environment. Organ...

ECOLOGY, ECOSYSTEM and ENVIRONMENT THE NATURE OF ECOLOGY Ecology is a study of connections in nature. How organisms interact with one another and with their nonliving environment. Organisms and Species Organisms, the different forms of life on earth, can be classified into different species based on certain characteristics.  Species Diversity and Niche Structure: Different Species Playing Different Roles Biological communities differ in the types and numbers of species they contain and the ecological roles those species play. Species diversity: the number of different species it contains (species richness) combined with the abundance of individuals within each of those species (species evenness). Indicator Species: Biological Smoke Alarms Species that serve as early warnings of damage to a community or an ecosystem. Presence or absence of trout species because they are sensitive to temperature and oxygen levels.  Case Study: Why are Amphibians Vanishing? Frogs serve as indicator species because different parts of their life cycles can be easily disturbed.  Case Study: Why are Amphibians Vanishing? Habitat loss and fragmentation. Prolonged drought. Pollution. Increases in ultraviolet radiation. Parasites. Viral and Fungal diseases. Overhunting. Natural immigration or deliberate introduction of nonnative predators and competitors. Keystone Species: Major Players Keystone species help determine the types and numbers of other species in a community thereby helping to sustain it.  Foundation Species: Other Major Players Expansion of keystone species category. Foundation species can create and enhance habitats that can benefit other species in a community. Elephants push over, break, or uproot trees, creating forest openings promoting grass growth for other species to utilize. Population A group of individual organisms of the same species living w/in a particular area. Community The population of all species living & interacting in an area.  Ecosystem A community of different species interacting together & with the chemical & physical factors making up its non-living environment. Source: socratic.org  Nonliving and Living Components of Ecosystems Ecosystems consist of nonliving (abiotic) and living (biotic) components. Biotic Components The living organisms (or) living members in an ecosystem collectively form its community called biotic components (or) biotic community. Examples Plants (producers), animals (consumers), microorganisms (decomposers). Abiotic Components The non-living components (physical and chemical) of ecosystem Examples Climate, soil, water l air, energy, nutrients, etc., 1. Physical components They include the energy, climate, raw materials and living space that the biological community needs. They are useful for the growth and maintenance of its member. Examples Air, water, soil, sunlight, etc., Abiotic Components 2. Chemical Components They are the sources of essential nutrients Examples Organic substances : Protein, lipids, carbohydrates, etc., Inorganic substances: All micro (Al, Co, Zu, Cu) and macro elements (C, H, O, P, N, K) and few other elements. TYPES of ECOSYSTEM Natural Ecosystem 1. Terrestrial ecosystem - this ecosystem is related to land. Example Grassland ecosystem, forest ecosystem, desert ecosystem, etc., 2. Aquatic ecosystem This ecosystem is related to water. It is further sub classified into two types based on salt content. A. Fresh water ecosystem Running water ecosystems. Examples Rivers, Streams Standing water ecosystems Examples Pond, lake Marine ecosystem Example : Seas and sea shores TYPES of ECOSYSTEM Man-made Ecosystem Artificial ecosystem operated or maintained by man. Example: Croplands, gardens Habitat Habitat is the physical environment in which an organism lives (address of an organism). Many habitats make up the environment. A single habitat may be common for more than one organism which have similar requirements. Habitat Difference between Habitat and Environment ▪ A habitat always has life in it, whereas the environment does not necessarily have life in it. ▪ All habitats are environments, but all environments are not habitats. ▪ A habitat is always a preference of one species. https://www.dkfindout.com/ Niche The total way of life or role of a species in an ecosystem. All the physical, chemical, and biological conditions a species needs to live & reproduce in an ecosystem.  Predator An organisms that captures & feeds on parts or all of another animal. Prey An organisms that is captured & serves as a source of food for another animal. Tragedy of the Commons A common-property resource, which are owned by no one but are available to all users free of charge. Most are potentially renewable. Ex. Clean air, open ocean and its fish, migratory birds, Antarctica, the ozone, and space. Carrying Capacity The maximum population of a particular species that a given habitat can support over time. Consumers: Eating and Recycling to Survive Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. Herbivores Primary consumers that eat producers Carnivores Primary consumers eat primary consumers Third and higher level consumers: carnivores that eat carnivores. Omnivores Feed on both plant and animals. Producers An organism that uses solar energy (green plant) or chemical energy (some bacteria) to manufacture its food. Primary Consumer (herbivore) An organism that feeds directly on all or parts of plants. Secondary Consumer (carnivore) An organisms that feeds only on primary consumers. Most are animals, but some are plants (Venus fly-trap). Tertiary Consumer (carnivore) Animals that feed on animal-eating animals. Ex. hawks, lions, bass, and sharks. Quaternary Consumer (carnivore) An animal that feeds on tertiary consumers. Ex. humans. Decomposer (scavenger, detritivore) An organism that digests parts of dead organisms, cast-off fragments, and wastes of living organisms. Ex. bacteria and fungi. Decomposers and Detrivores Decomposers: Recycle nutrients in ecosystems. Detrivores: Insects or other scavengers that feed on wastes or dead bodies. Function of an Ecosystem 3 types: Primary Function Secondary Function Tertiary Function  Abiotic chemicals Heat Heat (carbon dioxide, Solar oxygen, nitrogen, energy minerals) Heat Decomposers Producers (bacteria, fungi) (plants) Consumers (herbivores, Heat Heat carnivores)  Food Webs/Chains Purpose – determines how energy & nutrients move from one organism to another through the ecosystem Arrows – point from the producer to the consumer  First Trophic Second Trophic Third Trophic Fourth Trophic Level Level Level Level Producers Primary Secondary Tertiary (plants) consumers consumers consumers (herbivores) (carnivores) (top carnivores) Heat Heat Heat Solar energy Heat Heat Heat Heat Detritivores Heat (decomposers and detritus feeders) Structure Shows the decrease in usable energy available at each succeeding trophic level in a food chain or web. Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs In accordance with the 2nd law of thermodynamics, there is a decrease in the amount of energy available to each succeeding organism in a food chain or web. Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs Ecological efficiency: percentage of useable energy transferred as biomass from one trophic level to the next.  Relationship Between Biomass and Energy Biomass is dry weight & represents the chemical energy stored at each energy level. Water is neither a source of energy, nor has any nutritional value. 10% Rule We assume that 90% of the energy at each energy level is lost because the organism uses the energy. (heat) It is more efficient to eat lower on the energy pyramid. You get more out of it! This is why top predators are few in number & vulnerable to extinction. Energy Flow & Feeding Relationships Direction: grain steer human Measurement – samples are taken, dried, & weighed Description Two kinds of organisms, such as lions and zebras, are said to have a predator-prey relationship. Importance in Population Control Predators usually kill the sick, weak or aged. This helps to let the rest of the prey have greater access to the available food supply. It also improves the genetic stock. SPECIES INTERACTIONS: COMPETITION AND PREDATION Species can interact through competition, predation, parasitism, mutualism, and commensalism. Some species evolve adaptations that allow them to reduce or avoid competition for resources with other species (resource partitioning). Symbiosis Parasitism –when 1 species (parasite) feeds on part of another species (host) by living on or in it for a large portion of host's life. Commensalism – benefits one species but doesn't harm or help the other Mutualism – both species benefit Parasites: Sponging Off of Others Although parasites can harm their hosts, they can promote community biodiversity. Some parasites live in host (microorganisms, tapeworms). Some parasites live outside host (fleas, ticks, mistletoe plants, sea lampreys). Some have little contact with host (dump-nesting birds like cowbirds, some duck species) Mutualism: Win-Win Relationship Two species can interact in ways that benefit both of them. (a) Oxpeckers and black rhinoceros Commensalism: Using without Harming Some species interact in a way that helps one species but has little or no effect on the other.  Population Growth Cycle Limited Resources A population can grow until competition for limited resources increases & the carrying capacity (C.C.) is reached. Typical Phases 1. The population overshoots the C.C. 2. This is because of a reproductive time lag (the period required for the birth rate to fall & the death rate to rise). 3. The population has a dieback or crashes. 4. The carrying capacity is reached. Biodiversity Definition The many forms of life found on the Earth. “Wildness” Genetic Diversity – the variety of genetic make-up w/in a single species Species Diversity – the variety of species in different habitats on the Earth Importance It gives us food, wood, energy, free recycling, purification & natural pest control. Measurement Genetic tests, count/release, and tagging.  Succession The process where plants & animals of a particular area are replaced by other more complex species over time. Primary vs. Secondary Primary begins with a lifeless area where there is no soil (ex. bare rock). Soil formation begins with lichens or moss. Secondary begins in an area where the natural community has been disturbed, removed, or destroyed, but soil or bottom sediments remain. Pioneer Communities Lichens and moss.  Climax Communities The area dominated by a few, long-lived plant species.  Development (habitat destruction) Humans eliminate some wildlife habitats. TYPES OF SPECIES Native, nonnative, indicator, keystone, and foundation species play different ecological roles in communities. Native: those that normally live and thrive in a particular community. Nonnative species: those that migrate, deliberately or accidentally introduced into a community. Importation of Species Ex. The Chinese chestnut had a fungus that spread & virtually eliminated the American chestnut. Kudzu Introduced (invasive) species They displace native species They lower biodiversity The can adapt very quickly to local habitats They contribute to habitat fragmentation They can reproduce very quickly Hunting Over-hunting/hunting of top predators for big game. Pollution CFC’s, CO2, oil spills. Habitat Restoration Trying to rebuild what was ruined. Reclamation Returning vegetation to an area that has been mined or disturbed by human use. This can be done by re-planting, cleaning up pollution, regulations (laws) or any other activity designed to “fix” a destroyed area.  Agriculture Cut/burn techniques & the loss of habitat. Thank you for listening.