GE ELEC 1 - Unit 2 Chapter 1 - Ecosystems (What are they and how do they work) PDF

PEOPLE AND THE EARTH’S ECOSYSTEM ECOSYSTE MS: WHAT ARE THEY AND HOW THEY WORK?  CORE CASE STUDY Tropical rain forest are found near the earth’s equator and contain an incredible variety of life. These lush forests are warm year round and have high humidity and heavy rainfall almost daily. Al...

PEOPLE AND THE EARTH’S ECOSYSTEM ECOSYSTE MS: WHAT ARE THEY AND HOW THEY WORK?  CORE CASE STUDY Tropical rain forest are found near the earth’s equator and contain an incredible variety of life. These lush forests are warm year round and have high humidity and heavy rainfall almost daily. Although they cover only about 2% of the earth’s land surface, studies indicate that they contain up to half of the world’s known terrestrial plant and animal For these reasons, they make an excellent natural laboratory for the study species. of ecosystems− communities of organisms interacting with one another and with the physical environment of matter and energy in which they live.  CORE CASE STUDY So far, at least half of these forests have been destroyed or disturbed by humans cutting down trees, growing crops, grazing cattle, and building settlements, and the degradation of these centers of life (biodiversity) is increasing. Ecologists warn that without strong conservation measures, most of these forests will probably be gone or severely degraded within your lifetime. Scientists project that disrupting these ecosystems will have three major harmful effects. First, it will reduce the earth’s vital biodiversity by destroying or degrading the habitats of many of their unique plant and animal species, thereby causing their premature extinction. Second, it will help to accelerate climate change due to global warming by eliminating large areas of trees faster than they can grow back, thereby reducing the trees’ overall uptake of the greenhouse gas carbon dioxide.  CORE CASE STUDY Third, it will change regional weather patterns in ways that will prevent the return of diverse tropical rain forests in cleared or degraded areas. Once, this tipping point is reached, tropical rain forest in such areas will become less grassland. LESSON 1: What is ecology?  Definition of Terms  Ecology – is the study of the relationships between living organisms, including humans, and their physical environment; it seeks to understand the vital connections between plants and animals and the world around them. Ecology also provides information about the benefits of ecosystems and how we can use Earth’s resources in ways that leave the environment healthy for future generations.  Ecosystem – is a geographic area where plants, animals and other organisms, as well as weather and landscape, work together to form a bubble of life. An ecosystem has a living (biotic) and nonliving (abiotic) component.  Biotic factors – are living things within an ecosystem; such as plants, animals, and bacteria.  Definition of Terms  Abiotic factors – are non-living components; such as water, soil and atmosphere Biotic Factors Abiotic Factors Are they living Yes No things? Animals, plants, Forest fires, water, climate, Examples fungi, bacteria – all habitat, soil, minerals, living things human activity Atmosphere, chemical Producers, Main elements, consumers, categories sunlight/temperature, wind, decomposers and water Chemical and physical  Definition of Terms  Heterotrophy – organisms that ingest other organisms to obtain organic nutrients.  Heterotrophic organisms are consumers in the ecosystem because they cannot manufacture their own food.  However, there are also organisms that can produce their own food, called autotrophs. It include plants, algae, and certain bacteria like cyanobacteria, which carry out photosynthesis.  Definition of Terms  Decomposers – heterotrophic bacteria and fungi that obtain organic nutrients by breaking down the remains of products of organisms. The activities of decomposers allow simple compounds to be recycled back to the autotrophs.  Food chain – in ecology, the sequence of transfers of matter and energy in the form of food from organism to organism  Definition of Terms  Food web – is the natural interconnection of food chains and a graphical representation of what- eats-what in an ecological community.  Definition of Terms  Biogeochemical cycle – elements within biogeochemical cycles flow in various forms from the nonliving (abiotic) components of the biosphere to the living (biotic) components and back. In order for the living components of a major ecosystem (e.g., a lake or a forest) to survive, all the chemical elements that make up living cells must be recycled continuously  Definition of Terms  Nitrification – in this process, the ammonia is converted into nitrate by the presence of bacteria in the soil. Nitrites are formed by the oxidation of ammonia with the help of Nitrosomonas bacteria species. Later, the produced nitrites are converted into nitrates by Nitrobacter. This conversion is very important as ammonia gas is toxic for plants.  Definition of Terms  Ammonification – When an organism excretes waste or dies, the nitrogen in its tissues is in the form of organic nitrogen (e.g. amino acids, DNA). Various fungi and prokaryotes then decompose the tissue and release inorganic nitrogen back into the ecosystem as ammonia in the process known as ammonification.  Definition of Terms  Denitrification – is the natural conversion of nitrate (NO3–) ions to biologically inert nitrogen (N2) gas via the help of microorganisms. This process helps in retaining bioavailable nitrogen back in the atmosphere. N2, or the dinitrogen gas, is the final end product of interest though other forms of gaseous nitrogen may be released into the environment as a result of denitrification.  Definition of Terms  Eutrophication – is the process in which a water body becomes overly enriched with nutrients, leading to the plentiful growth of simple plant life. The excessive growth (or bloom) of algae and plankton in a water body are indicators of this process. Eutrophication is considered to be a serious environmental concern since it often results in the deterioration of water quality and the depletion of dissolved oxygen in water bodies. Eutrophic waters can eventually  Definition of Terms  Biomass – is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms, plants or animals. The mass can be expressed as the average mass per unit area, or as the total mass in the community.  Definition of Terms  Community – the population of all species that occupy a habitat.  Tropical level – A trophic level refers to a level or a position in a food chain, a food web, or an ecological pyramid. It is occupied by a group of organisms that have a similar feeding mode.  Definition of Terms  There are five trophic levels in a food chain. They are listed below with examples and food sources. Trophic Level Food Source Examples First Trophic Level Prepares their food Green plans and algae Grasshoppers, Second Trophic Feeds on producers butterflies, deer, and Level cows Feeds on primary Frogs, rats, mice, and Third Trophic Level consumers sparrow Fourth Trophic Feeds on secondary Snake, owl Level consumers Feeds on tertiary Fifth Trophic Level Hawk  Definition of Terms  Nitrogen fixation – is a chemical process that converts atmospheric nitrogen into ammonia, which is absorbed by organisms. Nitrogen fixation is essentially converting atmospheric nitrogen into a form that plants can more readily utilize. LESSON 2: Introduction and Scope of Ecology  ECOLOGY It is the study of the relationships between living organisms, including humans, and their physical environment; it seeks to understand the vital connections between plants and animals and the world around them.  Levels of Ecological Organization Ecosystems can be studied at small levels or at large levels. The levels of organization are described below from smallest to the largest:  Levels of Ecological Organization  Individual – It is the lowest level of organization in an ecosystem. An organism or individual is a single organism, plant, animal, or microorganism, such as bacteria and fungi, capable of independent existence, functioning independently, and can reproduce.  Niche – describes the role an organism plays in a community. For example, a garden spider is a predator that hunts for prey among plants  Population – A population is a group of similar individuals, usually of a given species occupying a particular habitat at a particular time. This group consists of organisms that feed and move together and interbreed among themselves to reproduce.  Community – A community includes populations of different species living together and sharing the same habitat in a given  Levels of Ecological Organization  Ecosystem – It is a functional unit of nature consisting of more than a community of living organisms (biotic factors) and their interaction with non-living ones (abiotic factors).  Biome - A large group of ecosystems that are characterized by soil and climate type. Major Biomes of the World Rainforest Grassland Desert Aquatic Tundra  Levels of Ecological Organization  Biosphere – It is the highest and broadest level of ecological organization. A biosphere is the total of all the ecosystems on the planet Earth. Thus, it encompasses all living organisms and the part of the atmosphere involving oceans, mountaintops, trees, and others. The biosphere refers to the part of the Earth’s crust.  Spheres of the Earth The Earth’s life-support system has four major components. Scientists’ studies reveal that the earth’s life-support system consists of four main spherical systems that interact with one another.  Spheres of the Earth  Atmosphere – Atmos means “air.” The atmosphere includes all the gases surrounding the Earth. All planets have an atmosphere, but Earth is the only planet with the correct combination of gases to support life. The atmosphere consists of five layers and is responsible for Earth’s weather. Even though it seems like air is made of nothing, it consists of particles too small to be seen. All these particles have weight that push down on Earth. The weight of air above us is called air pressure.  Hydrosphere – Hydro means “water.“ The hydrosphere includes the oceans, rivers, lakes, groundwater, and water frozen in glaciers. 97% of water on Earth is found in the oceans. Water is one of the most important substances needed for life and makes up about 90% of living things. Without water, life would not be possible.  Spheres of the Earth  Geosphere – Geo means “earth.” The Earth’s geosphere (sometimes called the lithosphere) is the portion of the earth that includes rocks and minerals. It starts at the ground and extends all the way down to Earth’s core. We rely on the geosphere to provide natural resources and a place to grow food. Volcanos, mountain ranges, and deserts are all part of the geosphere.  Biosphere – Bio means “life.” The biosphere is made up of all the living things on Earth and it includes fish, birds, plants, and even people. The living portion of the Earth interacts with all the other spheres. Living things need water (hydrosphere), chemicals from the atmosphere, and nutrients gained by eating things in the biosphere.  Spheres of the Earth The four spheres interact. The spheres interact to effect Earth’s systems and processes, and they are constantly changing each other. For example, ocean currents (hydrosphere) affect air temperature (atmosphere). Another example of how the spheres affect each other is through erosion. Erosion happens in the desert when wind (atmosphere) shapes the sand in the geosphere. Water (hydrosphere) can also shape land, such as in the formation of the Grand Canyon.  Spheres of the Earth Humans can have major impacts on all the spheres. Humans have a huge impact on all spheres. Negative impacts, such as burning fossil fuels, pollute the atmosphere. Piling up our waste in landfills affects the geosphere. Pumping waste into the oceans harms the hydrosphere. And overfishing and habitat destruction can reduce the diversity of living things in the biosphere. However, people everywhere are working to change things. Recycling efforts are increasing all over the world, and companies are finding new ways to reduce fossil fuels. In the US alone, people are recycling six times more  Three Factors Sustain Life on Earth Life on the earth depends on three interconnected factors:  The one-way flow of high-quality energy from the sun, through living things in their feeding nutrients, into the environment as low-quality energy (most heat dispersed into air or water at a low temperature), and eventually back into space as heat. No round trips are allowed because high-quality energy cannot be recycled. The first and second laws of thermodynamics govern this energy flow. Environ Radiati Living Sun plants ment as on to things heat space  Three Factors Sustain Life on Earth  The cycling of matter or nutrients (the atoms, ions, and compounds needed for survival by living organisms) through parts of the biosphere. Because the earth is closed to significant inputs of matter from space, its essentially fixed supply of nutrients must be continually recycled to support life. Nutrient movements in ecosystems and in the biosphere are round- trips, which can take from seconds to centuries to complete. The law of conservation of matter governs  Three Factors Sustain Life on Earth  Gravity – which allows the planet to hold onto its atmosphere and helps to enable the movement and cycling of chemicals through the air, water, soil, and, organisms. LESSON 3: Major Components of an Ecosystem  Major Components of an Ecosystem Ecosystems Have Living and Nonliving Components The term `eco' refers to a part of the world and `system' refers to the coordinating units. The living organisms of a habitat and their surrounding environment function together as a single unit. This ecological unit is called as an `ecosystem’. An ecosystem has a living (biotic) and nonliving (abiotic) component. Biotic Abiotic  Major Components of an Ecosystem Producers and Consumers Are the Living Components of Ecosystems Ecologists assign every organism in an ecosystem to a feeding level, or trophic level, depending on its source of food or nutrients. The organisms that transfer energy and nutrients from one trophic level to another in an ecosystem can be broadly classified as producers and consumers. Producers are sometimes called autotrophs (self-feeders), make the nutrients they need from compounds and energy obtained from their environment. On land, most producers are green plants, which capture about 1% of the solar energy that falls on their leaves and convert it to chemical energy stored in organic molecules such as carbohydrates. In fresh water and marine ecosystems, algae and aquatic plants are the major producers  Major Components of an Ecosystem All other organisms in an ecosystem are consumers, or heterotrophs (other-feeders), that cannot produce the nutrients they need through photosynthesis or other processes and must obtain their nutrients by feeding on other organisms (producers or other consumers) or their remains. There are several types of consumers:  Primary consumers, or herbivores (plant eaters), are animals such as rabbits, grasshoppers, deer, zooplankton that eat producers, mostly by feeding on green plants.  Secondary consumers, or carnivores (meat eaters), are animals such as spiders, hyenas, birds, frogs, and some zooplankton-eating fish, all of which feed on the flesh of herbivores. Major Components of an Ecosystem  Third- and higher-level consumers are carnivores such as tigers, wolves, mice-eating snakes, hawks, and killer whales (orcas) that feed on the flesh of other carnivores.  Omnivores such as pigs, foxes, cockroaches, and humans, play dual roles by feeding on both plants and animals.  Detritus feeders, or detritivores, feed on the wastes or dad bodies of other organisms, called detritus (meaning debris). Examples include small organisms such as mites and earthworms, some insects, catfish, and larger scavenger organisms such as vultures.  Decomposers, heterotrophic bacteria and fungi that obtain organic nutrients by breaking down the remains of products of organisms. The activities of decomposers allow simple