Presentation on theme: "Ecology Study of interactions among organisms and between organisms and their environment. Coined by Ernst Haeckel from – Oikos = house – Logos = study."— Presentation transcript:
Ecology Study of interactions among organisms and between organisms and their environment. Coined by Ernst Haeckel from – Oikos = house – Logos = study of
Biosphere Combined areas of the Earth where life exists – includes land, water, and air From about 8 kilometers above Earth to 11 kilometers below ocean surface
Biosphere is composed of three main parts 1. lithosphere – soil and rock of Earth’s crust 2. atmosphere – gases surrounding Earth 3. hydrosphere – all of Earth’s water -is a closed system for matter, while energy from the sun flows through the systems
Levels of Organization Ecologists study organisms and their environment at many different levels: 1. Species - group of similar organisms that can and do breed in nature to produce fertile offspring.
2. Populations - members of a species that live in the same area at the same time
3. Community - groups of different populations that live together in a defined area
4. Ecosystem - all of the organisms in a given area together with their nonliving, or physical, environment (abiotic)
5. Biome - group of ecosystems that have the same climate and similar dominant communities 6. Biosphere Ecological Methods Ecologists use the Scientific Method for discovering more about the natural world. Three basic approaches: 1. Observation – first step in asking questions 2. Experimenting – used to test hypotheses - Laboratory vs. Field - manipulating variables
3. Modeling – models are developed to gain insight into complex phenomena such as global warming on ecosystems. Exploring Ecology from Space - to understand global ecology requires remote sensing satellites - optical sensors can sense heat, light, and other wavelengths and convert that information into data - can assess such things as carbon dioxide levels, temperature, land use changes, forest destruction, etc.
Energy Flow All organisms require energy to power life’s process Energy flows through ecosystems Producers Organisms that are capable of using energy to produce organic compounds from inorganic compounds Sunlight is main energy source for all living organisms – Less than 1% of sunlight that reaches the Earth’s surface is used by producers
Photosynthesis is the most important chemical reaction on Earth for life because it can bring non-living CO 2 into the realm of life. Converts CO 2 and water to simple sugars 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Chemosynthesis – used by some producers to get energy from inorganic compounds Autotrophs – Organisms which can produce their own food – Use energy from the environment to assemble simple inorganic molecules into large organic molecules
Consumers = Heterotrophs Organisms which cannot make their own food from inorganic molecules Must consume other organisms for energy and food supply Herbivores – eat plants Carnivores – eat animals Omnivores – eat both plants and animals Detritivores – eat detritus (remains of dead organisms) Decomposers – break down organic matter into inorganic compounds
Food Chain - series of organisms which transfer energy and matter from one to the other in feeding relationships Trophic Levels - each step in a food chain
Food Webs - all of the interconnected food chains in an ecosystem.
Ecological Pyramids - diagrams which show the relative amounts of energy, matter, or number of organisms at each trophic level - most look like a pyramid because of decreasing amounts of what is being measured as you move up trophic levels in an ecosystem - pyramid of biomass and pyramid of numbers can sometimes be inverted
Energy Pyramid – only about 10% of energy passes from one trophic level to the next. - limits the number of trophic levels in an ecosystem
Pyramid of Numbers – shows numbers of individuals at each trophic level. - sometimes is inverted due to fewer producers
Biomass Pyramid –shows the amount of living tissue at each trophic level.
Cycles of Matter While energy flows through ecosystems, matter is recycled repeatedly from non-living sources through living organisms and back to the abiotic world. Biogeochemical Cycles – cycles which move matter through and between ecosystems and connect biological, geological, and chemical aspects of the biosphere. Matter isn’t used up, but transformed by living organisms.
Nutrient Cycles Organisms need nutrients to build tissues and carry out essential life functions. Primary producers are able to bring nutrients in as simple inorganic forms and convert them to organic compounds. Carbon Cycle Biological process such as photosynthesis, respiration, and decomposition take up and release carbon dioxide and oxygen Geochemical processes such as erosion and volcanic activity release carbon dioxide to the atmosphere.
Mixed biogeochemical process such as burial and decomposition of dead organisms and conversion under pressure to fossil fuels store carbon underground Human activities such as mining, cutting and burning forests, and burning fossil fuels release carbon dioxide into the atmosphere.
Nitrogen Cycle All organisms need nitrogen to make amino acids which are used to build proteins Nitrogen gas makes up 78% of the atmosphere Several types of bacteria convert nitrogen from one form to another Nitrogen fixation converts nitrogen gas into ammonia which can be converted into usable nitrates and nitrites. Bacteria in the nodules of legumes do nitrogen fixation Lightning converts nitrogen gas to usable nitrates and nitrites
Producers use nitrates and nitrites and consumers get their nitrogen from the producers Denitrification converts nitrates back into nitrogen gas Humans add nitrates to the biosphere in our fertilizers The Cape Grim Baseline Air Pollution Station in Tasmania, where air samples have been collected since 1978. These samples show a long-term trend in isotopic composition that confirms that nitrogen-based fertilizer is largely responsible for the 20 percent increase in atmospheric nitrous oxide since the Industrial Revolution. Photo courtesy of CSIRO.
Primary Productivity – rate at which organic matter is created by producers - available nutrients help control productivity
Nutrient Limitation When an ecosystem is limited by a single nutrient that is scarce or cycles very slowly this substance is called a limiting nutrient. Farmers apply fertilizers to make up for this When fertilizers run-off into water they sometimes cause algal blooms – Algae grow rapidly and sometimes cover the water – When algae die, their decomposition removes oxygen from the water and causes many animals to die.
Eutrophication - increase in plant growth in water - water is more rich in nutrients What is Eutrophication? Eutrophication is a process where bodies of water, such as lakes, estuaries, or slow-moving streams, receive excess nutrients that stimulate excessive plant growth. This enhanced plant growth, often called an algal bloom, reduces dissolved oxygen in the water. This can kill other marine life which also depend on dissolved oxygen in the water.