Ecology Ecology: the study of how living things interact with their physical environment To be used with Ecology Guided Notes Gaccione/Bakka—Belleville High School Ecological Organization Organism • A living thing • Anything that possesses all of the characteristics of life Ecological Organization • Species: a group of organisms that can mate & produce a fertile offspring Ecological Organization • Population: all the members a species that live in certain place at a certain time. Ecological Organization • Community: a collection of interacting populations in an area Ecological Organization • Ecosystem: includes all of the organisms & the non-living environment. – community members in the ecosystem must interact to maintain a balance. Ecological Organization • Biosphere: the portion of the earth where all life exists. A 13 mile band that surrounds the earth. 6-7 miles into the atmosphere & 6-7 miles deep into the ocean. – Composed of many complex ecosystems. Put in order:(small to large) community Population species biosphere organism ecosystem Ecosystems An ecosystem is self-sustaining if: 1. A constant source of energy is supplied. 2. Living things use this energy and convert into organic molecules 3. A cycling of materials between organisms and their environment Resources • Organisms with similar needs may compete with each other for resources like: 1. Food 2. Space 3. Water 4. Air 5. Shelter Limiting Factors • Limiting Factor: anything that makes it more difficult for a species to live, grow, or reproduce in its environment – Determines the types of organisms that exist in that environment Acclimation when organisms acclimate to changes • Range of Tolerance: the ability of an organism to withstand changes in their environment. Abiotic Factors • Abiotic factors: nonliving factors which affect the ability of organisms to survive and reproduce Examples: 1. intensity of light 2. range of temperatures 3. amount of moisture 4. soil or rock type 5. availability of inorganic substances 6. supply of gases such as oxygen, carbon dioxide, and nitrogen 7. pH Examples of Abiotic Factors What abiotic factors limit vegetation at higher altitudes? 1. 2. 3. 4. lack of soil a low annual temperature strong winds steepness of the grade Examples of Abiotic Factors What abiotic factors allow rainbow trout to love mountain streams? the amount of dissolved oxygen due to current water temperature no pollution pH of 7 shelter river bottom for reproduction Examples of Abiotic Factors What abiotic factors limit the organisms that can live there? temperature sunlight lack of water winds shelter/shade Biotic Factors • Biotic factors: living factors which affect the ability of organisms to survive and reproduce – Examples: • other organisms, such as a predator, food source Can an abiotic factor such as RAIN affect many biotic factors? grass - ________ mole eagle Rain - ________ - _________ Nutritional Relationships • Two types : Autotrophs & Heterotrophs – Autotrophs: organisms that synthesize their own food from inorganic molecules Plants that contain photosynthetic pigments, such as chlorophyll. Nutritional Relationships • Two types : Autotrophs & Heterotroph – Heterotrophs: can NOT synthesize their own food and are dependent on other organisms for their food Types of Heterotrophs • Saprophytes: include those heterotrophic plants, fungi, and bacteria which live on dead matter (a.k.a. decomposers or detritivores) Types of Heterotrophs • Herbivores: plant-eating animals Types of Heterotrophs Omnivores: • consume both plants and meat Types of Heterotrophs • Carnivores: meat-eating animals Types of Carnivores Predators: animals which kill and consume their other animals (prey) Prey: animals which are killed by predators More Predator/Prey Relationships Types of Carnivores Scavengers: those animals that feed on other animals that they have not killed Examples: crows vultures hyenas Which is the Predator? Symbiotic Relationships • Symbiosis: living together with another organism in close association –Types of symbiosis: • Commensalism • Mutualism • Parasitism Types of Symbiosis • Commensalism: one organism is benefited and the other is unharmed (+,0) – Example: barnacles on whales, orchids on tropical trees Types of Symbiosis • Mutualism: both organisms benefit from the association (+,+) – Example: Nile crocodile opening its mouth to permit the Egyptian plover to feed on any leeches attached to its gums. Types of Symbiosis • Parasitism: one organism benefits at the expense of the host (+,-) – Example: tapeworm and heartworm in dogs athlete's foot fungus on humans leech sucking blood from host Symbiosis Mutualism Parasitism Commensalism Energy Flow in an Ecosystem • Food chain: a single pathway of feeding relationships among organisms that involves the transfer of energy. Food Webs • Food web: Interrelated food chains in a community – Most organisms may be consumed by more than one species Trophic Levels An organism’s position in a sequence of energy transfers Fourth trophic Third trophic Second trophic First trophic level Energy Transfer • There is a decrease in the overall energy as you move up in trophic levels. • There is much more energy in the producer level in a food web than at the consumer levels • Approximately 10% of ingested nutrients is passed on to the next trophic level to build new tissue Energy Flow, continued Why is the % of energy passed on to the next trophic level so low? • No transfer of energy 100%, therefore some energy is lost in the form of heat • Some animals escape from being eaten & just die. Their energy in their bodies do not pass to a higher energy level. • Some animal parts can not be eaten. Cougar eats deer, can not extract energy from antlers, hooves or hair. Biomass: amount of organic matter producers primary consumers secondary consumers tertiary consumers Terrestrial Energy Pyramid Eagles Snakes Mice Green Plants Complete the Energy Pyramid using these organisms: Eagles, Green Plants, Mice, and Snakes Succession • Succession: a gradual process of change and replacement of populations in a community. – Succession occurs when the environment is altered. – These changes cause species to replace others, resulting in long-term gradual changes in ecosystems – Ecosystems tend to change until a climax community is formed. Primary Succession • The development of plant communities in an area that has never supported life. • examples: bare rock, lava flow or glaciers. Primary Succession - in a Pond The Start of Primary Succession • Pioneer organisms: the first organisms to inhabit a given location (example: lichens on bare rock) – Breaks down rock into soil – Establish conditions under which more advanced organisms can live. Primary Succession Example Adirondack Bog Succession 1. water plants at pond edge 2. sedges and sediments begin to fill pond 3. sphagnum moss and bog shrubs fill pond (cranberries) 4. black spruce and larch 5. birches, maple, or fir Secondary Succession • is the change of species that follows disruption of an existing community • created by natural disasters or human activity • Occurs in areas that previously contained life and SOIL!!! • forest fire at Yellowstone National Park. Secondary Succession Example • If the BHS football field is not mowed, would it be primary or secondary succession? Primary or Secondary Succession? Primary on rock Secondary on soil. Climax Community • Climax community: a community that has reach a stable state. – populations remain stable and exist in balance with each other and their environment – ecosystems may reach a point of stability that can last for hundreds or thousands of years Climax Community • A climax community persists until a catastrophic change alters or destroys a major biotic or abiotic resource – (ex. forest fires, abandoned farmlands, floods, areas where the topsoil has been removed) • After the original climax community has been destroyed, the damaged ecosystem is likely to recover in stages that eventually result in a stable system similar to the original one. Biomes • Biome: a large region characterized by a specific type of climate & certain plant and animal communities. • A certain biome may exist in more than one location on earth. • Biomes are terrestrial (dry) or aquatic (wet) – Dependent on: • Temperature • Solar radiation • Precipitation Terrestrial Biomes • Terrestrial Biomes: – In general, six land biomes – Characterized by climax vegetation – Have characteristic flora (plants) and fauna (animals) Terrestrial Biomes: Tundra • Climax flora: treeless. lichens, mosses, grasses • Climax fauna: caribou, snowy owl • Characteristics: long & extremely cold winters & permanently frozen subsoil called permafrost • Location: Continuous belt around N America, Europe & Asia Terrestrial Biomes: Taiga • Climax flora: conifers or evergreen trees • Climax fauna: moose, black bear, squirrels • Characteristics: long, severe winters • Location: south of the tundra & north of temperate forest Terrestrial Biomes: TemperateDeciduous Forest • Climax flora: trees that shed leaves • Climax fauna: gray squirrel, fox, deer • Characteristics: moderate precipitation, cold winters, warm summers • Location: South of taiga Terrestrial Biomes: Tropical Forest • Climax flora: many species of broad-leaved plants • Climax fauna: snake, monkey, and leopard • Characteristics: heavy rainfall(300 inches/year), constant warmth • Biodiversity: The size of 2 football fields may have 300 species of trees • Location: Near the equator Terrestrial Biomes: Grasslands • Climax flora: grasses • Climax fauna: prairie dog, bison, usually herd animals. • Characteristics: rainfall and temperature vary greatly, strong winds • Grasslands: also known as prairies, steppes, savannas & pampas. • Location: interior of continents Terrestrial Biomes: Desert • Climax flora: droughtresistant shrubs and plants • Climax fauna: kangaroo rat, lizard • Characteristics: sparse rainfall (9 inches/year). • Extreme temperature. Hot days cool nights. Temperatures may have a 50 degree drop. Aquatic Biomes • Aquatic Biomes: the largest ecosystems on Earth – 70% of Earth’s surface is covered by water – Water is the principal medium for life – More stable then terrestrial biomes • Moisture not a limiting factor • Temperature changes are not as great 2 Types of Aquatic Biomes • Marine Biomes: salt water biomes – Most stable aquatic environment – Habitat for large number of diverse organisms • Freshwater Biomes: ponds, lakes, rivers & wetlands – Will fill in due to seasonal die-back and erosion – Eventually terminate in a terrestrial climax community Freshwater Biomes • 2 Types of Lakes: 1. Eutrophic -rich in organic matter & vegetation Murky water Bacteria feed on decomposing matter & uses up all the oxygen, killing all life. 2. Oligotrophic -little organic matter & vegetation Clear water. Freshwater Biomes • Wetlands: aka swamps & marshes an area of land that is covered by water for a certain amount of time during the year. Why are wetlands so important? filters out pollutants controls flooding stopover for migratory birds recreational Zone of Photosynthesis • Plant production occurs at the edges of land masses • No light penetrates the deeper regions of aquatic biomes Aphotic Competition • Competition: occurs when two different species or organisms living in the same environment (habitat) utilize the same limited resources – Examples: • food, water, space, light, oxygen, and minerals. • The more similar the requirements of the organisms involved, the more intense the competition. Organisms in Ecosystem • Habitat: – A place where an organism lives out its life. It is an organism’s home, their address. • Niche: - The organism's role in the community. How an organism meets its need for food, shelter, how it survives & reproduces. Interactions with biotic & abiotic factors. Material Cycles • Material Cycles: – In a self-sustaining ecosystem, materials must be recycled among the organisms and the abiotic environment. – The same materials can be reused. – Examples of Cycles: • Water • Carbon-Oxygen • Nitrogen Water Cycle • Water Cycle: involves the processes of – Photosynthesis – Transpiration – Evaporation and condensation – Respiration – Excretion Water Cycle Carbon-Oxygen Cycles • Carbon-Oxygen Cycle: involves the processes of – Respiration – Photosynthesis Carbon-Oxygen Cycle oxygen Nitrogen Cycle • Nitrogen Cycle: – Organisms must have nitrogen to produce proteins and amino acids – Living things cannot use nitrogen gas in the air – Life is possible due to nitrogen-fixation • Nitrogen Fixation: Nitrogen gas is converted to ammonia Nitrogen Fixers • Legumes: peas and beans contain nitrogen-fixing bacteria in their roots – Clover and alfalfa are other examples of nitrogen fixers Bean Plant Alfalfa Nitrogen Cycle Nitrogen Gas (N2) Nitrogen fixation Animals eating plants Decomposition Nitrogen-fixing bacteria in plant roots Soil bacteria Biodiversity • • Evolutionary processes have resulted in a diversity of organisms and a diversity of roles in ecosystems. Biodiversity: the differences in living things in an ecosystem 1. Increased biodiversity increases the stability of an ecosystem. 2. Increased biodiversity increases the chance that at least some living things will survive in the face of large changes in the environment What are some other reasons biodiversity is valuable? 3. Biodiversity ensures the availability of a rich variety of genetic material that may lead to future agricultural or medical discoveries with significant value to humans. 4. Biodiversity adds aesthetic qualities to the environment Monoculture • Monoculture: planting one species over a huge area – Why? – Leaves an area more vulnerable to predation or disease GLOBAL BIODIVERSITY VALUE A map showing the distribution of some of the most highly valued terrestrial biodiversity world-wide (mammals, reptiles, amphibians and seed plants), with red for high biodiversity and blue for low biodiversity High Biodiversity vs. Low Biodiversity