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Biology 1 Introduction to Ecology Ecology: the study of the relationships living things have with each other and their non-living environment. Biotic Factors: all the living things in an environment What biotic factors can you identify? Abiotic Factors: All the non-living factors in an environment. The soil (dirt) in an environment cannot be called simply abiotic or biotic. Discuss. Species: a group of organisms that can interbreed and produce fertile offspring in nature. A few shark species What does it mean that these sharks are different species? Vocabulary Habitat (address) The place an organism lives. Think of a zoo. There is usually an attempt to mimic the organism’s “habitat.” Niche (occupation) The role that an organism plays in its environment. How does the organism obtain food? What are some of its relationships with other organisms? Can you describe the habitat and niche of some organisms? Vocabulary: Levels of Ecology Organism (any single living thing) Population (members of same species living in one place) Community (different populations interacting in an area) Ecosystem (a complete community + its abiotic environment) Biosphere (all parts of Earth where life exists, both biotic and abiotic) Population: a group of the same species living in the same area at the same time. Community: interacting groups of populations Ecosystem: a community and its abiotic environment. humidity light Water temperature Mineral content A Freshwater Pond Biomes (not required): Large, ecologically similar areas. Biosphere: all the interdependent and interrelated ecosystems of the earth Population Ecology: the interactions of one population, especially relating to population size What increases population size? • Natality (births) • Immigration (moving into a population) What decreases population size? • Mortality (deaths) • Emigration (moving out of a population) What are some factors that would influence natality and mortality rates? Immigration and emigration? Natural Resources: • Things organisms need to survive Limiting Factors (environmental resistance): • When resources are in short supply (or too abundant) and impact population growth. Carrying capacity: the maximum population than an environment can sustainably support Compare and contrast these graphs. A population may plateau OR temporarily overshoot the carrying capacity. If overshot, survival depends of severity of overshoot and speed of environmental recovery. Apply population ecology ideas to the global human population. COMMUNITY INTERACTIONS: Relationships between species 3 types of Symbiosis: A continuing and close relationship between species Relationship Mutualism Effect + / + Commensalism + / 0 Parasitism + / - Pathogen / Host Predator / Prey Not considered symbiosis Herbivore / Plant Competition + / + / + / - / - MUTUALISM: a + / + interaction Lichens: an alga and a fungus! What benefit does each species receive? MUTUALISM: a + / + interaction Cleaner Wrasse and Parrot Fish Ants and Acacia Trees What benefit does each species receive? MUTUALISM: a + / + interaction Ants and Aphids PARASITISM: a + / - interaction PARASITISM: The Cuckoo PATHOGEN / HOST: a + / - interaction COMMENSALISM: a + / 0 interaction Scavengers benefit from dead organisms that are not affected. Cattle Egrets eat the insects that these cattle scare up. COMMENSALISM: a + / 0 interaction Shark and Remora PREDATION: a + / - interaction HERBIVORY: a + / - interaction COMPETITION: a - / - interaction Male weaver birds: compete to attract a mate. This is INTRASPECIFIC competition: competition within the same species COMPETITION: a - / - interaction Invasive starlings will out-compete native bluebirds for nesting holes. This is INTERSPECIFIC competition: competition between different species Energy and Ecology: ALL living things need both matter and energy. Matter and energy are transferred: • between organisms • between organisms and the abiotic environment What is different between the transfer of ENERGY and the transfer of MATTER? ENERGY: flows one-way through the biosphere and leaves the Earth. A new input of energy is continually needed. MATTER: the same atoms are use over and over again. Matter is recycled, not “lost”. Energy and Ecology All organisms need energy to live. Where do you get your energy? How did the things you eat get their energy? Trace the energy back to its source. What is the source of energy for (almost) all living things? Ecology Vocabulary Tip: Learn word parts to help you understand new terms: Prefixes: “Auto” = by itself “Hetero” = from others Base-word: “Troph” = energy (obtaining food) Sometimes you see the suffix: “ic” = pertaining to Can you think of examples of words that have these parts? Trophic Levels: how organims obtain energy (their food) All organisms need energy to live. AUTOTROPHS (producers): Most use energy directly from the sun produce their own food by photosynthesis in chloroplasts often plants (also some bacteria, lichens, etc) Also break down food when and where needed to release energy (respiration) All organisms need energy to live. HETEROTROPHS get energy from consuming other organisms often animals that release energy by respiration in their mitochondria Two major types of Heterotrophs: Consumer - a living thing that eats other living things to survive. It cannot make its own food. Examples…humans, fish, spiders Decomposer - an organism that breaks down and digest the remains of organisms. Examples…. fungi and some bacteria Decomposers are essential because they are the nutrient recyclers! Kinds of Decomposers: 1.) detritovore: (have a mouth) feed on dead organisms or their wastes eg. worms, millipedes, dung beetles 2.) Saprotroph: (without a mouth) secrete digestive enzymes into their environment and absorb the nutrients. eg. Bacteria, fungi What is the difference between Detritivores and Saprotrophs? • Detritivores usually have mouths, Saprotrophs do not. • Detritivores are mostly animals while saprotrophs are mostly bacteria and fungi. • Detritivores consume lumps of dead organic matter separately, while saprotrophs absorb chemically digested food. • Saprotrophs digest their food externally, whereas detritivores do it internally in their digestive system. Remember to follow the energy! Find several major errors / omissions in this diagram (from a respected publisher!) Food chain: One possible energy pathway through an ecosystem. Shows who eats whom. Let’s play “follow the energy!” The arrows show you where it goes! Food web: All possible energy pathways through an ecosystem. Shows alternative food choices. Trophic Levels and Levels of Consumers Fourth Trophic Level Third Trophic Level Second Trophic Level First Trophic Level Note that the trophic level is always one more than the consumer level. Why? Food Web: Problems with Trophic Levels What is the trophic level of the fox? 3 4 5 4 3 3 2 1 2 2 1 1 We know that energy is transferred. How much? About 10% between trophic levels. Trophic Level: Position in a food chain Energy Efficiency in Food Consumption Why is it said that eating vegetarian food can reduce food shortages and starvation? Energy is not created or destroyed. If only 10% of energy is transferred to the next trophic level, where is the rest? Why can only 10% of energy be transferred to the next trophic level? • Not all organisms are eaten • Not all parts of organisms can be digested • Converting energy for the functions of life is not 100% efficient (some is always) lost as heat Cycles in Nature: ALL living things need both matter and energy. Matter and energy are transferred: • between organisms • between organisms and the abiotic environment What is different between the transfer of ENERGY and the transfer of MATTER? ENERGY: flows one-way through the biosphere and leaves the Earth. A new input of energy is continually needed. MATTER: the same atoms are use over and over again. Matter is recycled, not “lost”. Cycles of Matter: Water, Carbon, Nitrogen, etc. CARBON CYCLE Follow the carbon atoms. Where do they go? combustion Biodiversity What does “Bio” mean? Bio = Biodiversity What does “Diversity” mean? Diversity = Variety There are 3 components of biodiversity 1. Diversity within genes Chihuahuas, beagles, and Rottweilers are all dogs— but they're not the same because their alleles are different. Chihuahua Beagle Rottweilers 3 components of biodiversity 2. Diversity of species For example, there about 260 species of monkeys, 5,000 species of dragonflies, and 350,000 species of flowering plants. Saki Monkey Golden Skimmer Meadow Beauty 3 components of biodiversity 3. Variety of ecosystems Prairies, Ponds, and tropical rain forests are all ecosystems. Each one is different and supports a unique set of species. Paines Prairie Florida Sand hill Pond Hoh Rain Forest Which has more biodiversity? A B Threats to biodiversity 1. Habitat destruction or loss including 1. 2. 3. Land cleared for agriculture, construction, resource extraction, etc. Climate change impacts Pollution 2. Invasive Species 3. Direct hunting or exploitation For a video about biodiversity watch “Extinction!” video from the evolution unit. Why do we want biodiversity? 1. Intrinsic Value = Something that has value in and of itself. Do we value all life? 2. Utilitarian Value = Something that has value as a means to an end. What do we get from biodiviersity? • Food, shelter, medicine, and other products • Stable ecosystems and epidemicresistant species • Ideas for research and sources of new information The Earth is losing species at an alarming rate • Some scientists estimate that dozens of species are going extinct each day, many of which humans never studied This periwinkle was used in traditional medicine and became endangered due to habitat destruction. Scientists found that it has anti-cancer properties. It now gives us cisplatin, one of our best treatments for leukemia. Madagascan Rosy Periwinkle We came close to losing this species. What else might we be losing every day without knowing it? Solutions, not just problems • Eco-Tipping Points – Small actions that lead to large positive changes – For more information • A Thailand case study – Reversing Tropical Deforestation – Video presentation