WARM-UP Questions 1. 2. 3. What do you think the basic needs of life are? What is the environment? How do you define life…what are 4 things all living organisms have in common? Ecology Interactions in the Environment What is Ecology? The science of ecology includes everything from global processes (above), the study of various marine and terrestrial habitats (middle) to individual interspecific interactions like predation and pollination (below). Ecology is… the study of the interactions between living organisms and their biotic and abiotic environments. Ecology is therefore the study of the relationship of plants and animals to their physical and biological environment. And the ENVIRONMENT is… The surroundings of an organism that affect its life and development. An environment is characterized by the ABIOTIC and BIOTIC factors. Abiotic factors are non-living. Abiotic factors include science like chemistry, physics and geology. Interactions of abiotic factors result in weather, seasonal changes, tides, air quality, and water quality Biotic factors are living and can be categorized within an Species ecosystem structure… Population Community ECOSYSTEM: all of the communities that live in an area together with the abiotic factors in the environment A dead tree is not alive but not considered abiotic….why? It was once living! Biotic features are all living things in the biosphere. The biosphere is all the parts of Earth that support life. This measures approximately 20km thick (12.4 miles)! Most life on Earth exists between 500m below the surface of the ocean and about 6km above sea level. What types of communities make up these ecosystems? What types of abiotic factors are influencing these ecosystems? How are Biotic Factors organized? King Philip Came Over For Great Soup! Kingdom - Phylum - Class - Order - Family - Genus - Species All biotic factors are grouped into major kingdoms based upon similar physical characteristics…we will deal with 6. Listed in descending order of complexity: Animalia Plantae Fungi Protista Eubacteria Archeobacteria Abiotic and Biotic factors are intimately intertwined…. Geographic location (latitude and longitude) determines abiotic factors such as temperature and climate….which in turn, dictates or forces a certain type of ecosystem to exist. Levels of Organization studied in Ecology… AN ORGANISM’S NICHE Habitat: the actual place an organism lives Niche: both living and nonliving parts of an ecosystem that determines an organism’s role in the ecosystem. If two species share the same niche, they will have various interactions. How can species interact? These relationships are complex. Each population of species interacts with other species, or biotic factors, as well as with the all of the abiotic factors. The niche of an organism and it’s interactions is determined by where it stands in the ecological structure of the ecosystem. -Producers -Consumers -Decomposers -Scavengers PRODUCERS Producers are autotrophic organisms that make their own food. Phototrophic organisms use photosynthesis and contain chlorophyll (Carbon Dioxide + Water + Sunlight =Sugar + Oxygen) Chemotrophic organisms use chemicals other than H20, such as H2S PRODUCERS!!! CONSUMERS Consumers are heterotrophic organisms that cannot make their own food. They must ingest (eat) other organisms. -Herbivores feed on vegetation (producers). -Carnivores feed on herbivores or on other carnivores. Secondary carnivores feed on herbivores, Tertiary consumers feed on other carnivores -Omnivores feed on both producers and consumers -Scavengers feed on dead or decaying organisms CONSUMERS!!! Scavengers feed on CARRION (dead or injured animal corpses) and dead plant biomass. Scavengers reduce the size of dead organic matter…Decomposers will finish the job! DECOMPOSERS are heterotrophs that recycle small, often microscopic bits of dead organic matter into inorganic nutrients availbe for plants to take up from the soil. Decomposers RECYCLE nutrients! BACTERIA and FUNGI are decomposers…most worms are plant scavengers! Energy in the Ecosystem Energy from the sun enters and ecosystem when producers used the energy to make organic matter through photosynthesis. Glucose is the primary energy source (carbohydrate) produced by photosynthesis. Consumers take in this energy when they eat producers or other consumers. Energy in the Ecosystem Plants absorb less than 1% of the sunlight that reaches them! However, photosynthetic organisms make 170 billion metric tons of food each year! The energy captured by producers is used to make cells in both producers and consumers. TROPHIC LEVELS Trophic levels are the different feeding levels of organisms in an ecosystem. Producers are the first trophic level and consumers make up several more. These relationships can be seen in an ecological pyramid. Biomass: the total amount of organic matter present in a trophic level. The biomass in each trophic level is the amount of energy- in the form of food- available to the next The Ten Percent Law Most of the energy that enters through organisms in a trophic level does not become biomass. Only energy used to make biomass remains available to the next level. When all of the energy losses are added together, only about 10% of the energy entering one trophic level forms biomass in the next trophic level. This is known as the 10 percent law. MORE Ten Percent Law The 10 percent law is the main reason that most food chains have five or less links. Because 90 percent of the food chain’s energy is lost at each level, the amount of available energy decreases quickly. 10 PERCENT LAW!! Heat and Movement Consumed Digested Growth Not Digested Waste Not Consumed Decomposers The majority of energy is lost via heat and movement! ECOLOGICAL PYRAMID Remember scavengers and decomposers can enter at any level! Tertiary Consumers= CARNIVORE EATING OTHER CARNIVORES Secondary Consumers= CARNIVORES EATING HERBIVORES Primary Consumers= HERBIVORES PRODUCERS = Autotrophic Plants Ecological Pyramids Relative amounts of energy are represented in an ecological pyramid: a diagram that shows the relative amounts of energy in different trophic levels in an ecosystem. An ecological pyramid can show energy, biomass, or the number of organisms in a food web. Ecological Pyramid: Energy Shows the relative transfer of energy (joules) from one trophic level to the next. Ecological Pyramid: Biomass Shows the relative amounts of organic matter (gram) from one trophic level to the next. Ecological Pyramid: Number of Organisms Shows the relative number of organisms at each trophic level. Food Chains A Food CHAIN is a series of organisms that transfer food between the trophic levels of an ecosystem using only one species at each level…a simple chain. The arrows represent the flow of energy from one organism to the next. The arrow points toward the organism doing the ‘eating’. Food Webs Ecosystems are not as simple as shown and not often explained by a single food chain… Food WEBS more accurately show the network of food chains representing the feeding relationships among organisms in an ecosystem. Most organisms feed on more than one type of organism at different trophic levels. How do Food Webs show complexity? The diversity and stability of an ecosystem is represented by more complex webs that have many species and many interactions (lots of arrows) because they are more stable…more resistant to disturbance by natural disaster or human interference. Why? Biological Magnification BIOLOGICAL MAGNIFICATION The concentration of a pollutant in organisms increases at higher trophic levels in the food web because these chemicals build-up in the fatty tissues of these organism and do not dissolve or flush-out of the organism. DDT & Mercury examples: DDT is a pesticide used to kill insects like malaria-carrying mosquitoes. However, this chemical will magnify in concentration in larger organisms like birds and mammals and harm their reproductive abilities. Bald eagle populations declined rapidly to the point of extinction as an endangered species as mother birds were not able to incubate or hatch their eggs because the eggs shells were too thin and would crush and break when sat upon to keep warm in the nest. Biological Magnification As the living organisms eats more, the concentration of these substances increases as they pass from one trophic level to the next. The day it Rained cats… A bizarre case of ecological damage from DDT occurred in Borneo after the World Health Organization sprayed huge amounts of the pesticide. The area's geckos, or lizards, feasted on the houseflies that had been killed by DDT. The geckos, in turn, were devoured by local cats. Unhappily, the cats perished in such large numbers from DDT poisoning that the rats they once kept in check began overrunning whole villages. Alarmed by the threat of plague, WHO officials were forced to replenish Borneo's supply of cats by parachute. RELATIONSHIPS IN THE ECOSYSTEM Predator/Prey: One organism (predator) will actively hunt and consume another (prey). Competition: two or more organisms of same or different species compete to use the same limited resources or basic needs Symbiotic Relationships Parasitism: an organism (parasite) lives in or on another (host) and feeds on it without immediately killing it Mutualism: a cooperative partnership between two species (both benefit) Commensalism: a relationship where one species benefits and the other remains unaffected Coevolution When two or more species evolve in response to each other, it is called coevolution. Examples of coevolution may be found between predators and their prey. Plants and insects represent a classic case of coevolution — one that is often, but not always, mutualistic. Many plants and their pollinators are so reliant on one another and their relationships are so exclusive that biologists have good reason to think that the “match” between the two is the result of a coevolutionary process.
