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ECOLOGY. Biosphere and Its Units ECOLOGY The study of the relationships between organisms and their environment. Not just related to pollution Unifying.

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Presentation on theme: "ECOLOGY. Biosphere and Its Units ECOLOGY The study of the relationships between organisms and their environment. Not just related to pollution Unifying."— Presentation transcript:


2 Biosphere and Its Units ECOLOGY The study of the relationships between organisms and their environment. Not just related to pollution Unifying factor is adaptation.

3 Biosphere Area of earth where life exists Most on or within a few meters of earth's surface. Some found 8 km high and some found 8 km below ocean surface. Smaller ecological units Population - all members of a species that live in same area and make up a breeding group Group of deer, trout in a lake. Community - All populations in an area

4 ECOSYSTEM An ecological unit that includes all interacting parts of an environment in an area. Abiotic Factors Nonliving components of ecosystem. Biotic Factors Living components of ecosystem.



7 ABIOTIC FACTORS Nonliving components of an ecosystem. Light, precipitation, temperature, slope/drainage of land, soil chemistry, and atmosphere. Abiotic factors may interact Stream flooding results in deposition of sediment Changing of river courses Creation of mountains or islands by volcanoes Landslides removing soil.

8 BIOTIC FACTORS Living components of an ecosystem. Plants, animals, protists, microorganisms Living things may interact Predation – predator kills prey for food. Symbiosis – relationship between two organisms Usually beneficial to one organism.

9 Abiotic and biotic factors may also interact Affect each other. Climate/soils determine type of plants in area; determines animals of area. Plants replenish oxygen – photosynthesis Overgrazing can result in loss of soil.

10 Ecosystem Structure HABITAT Place where an organism lives - "home" Provides food and shelter. Habitats may overlap NICHE Role or occupation; everything organism does in its habitat Organisms way of life includes habitat, feeding habits, reproductive behavior, and all other biological aspects of the organism. No two organisms can occupy the same niche. Habitats overlap, niches do not.

11 Trophic Levels Energy enters an ecosystem from the sun. Energy flows between organisms when one organism eats another. Trophic Level is defined by the relationship between what organism eats and what eats it. The feeding level in an ecosystem. Comes from Greek that means "food"

12 Trophic Levels Producers Autotrophic organisms that make their own food using solar or chemical energy Consumers Heterotrophic organisms that feed on producers either directly or indirectly for their energy. Decomposers Organisms that breakdown organic material and return it to the environment for use by producers - Heterotrophic.

13 PRODUCERS Autotrophic organisms that make their own food using solar or chemical energy. Plants, algae, and photosynthetic bacteria Manufacture all organic nutrients for ecosystem Also called primary producers. Occupy the First Trophic Level Primary Productivity of an ecosystem - rate at which solar energy is converted into organic compounds Gross Primary Productivity - total amount of energy produced, includes energy used by plant for own respiration Net Primary Productivity - rate at which plants store energy not used in plant respiration.


15 CONSUMERS Heterotrophs that feed on producers either directly or indirectly for their energy. Primary Consumer - feeds on producers Secondary Consumer - feeds on a primary consumer. Consumers may be classified on basis of food type Herbivore - eats primary producers; "Plant eater" Carnivore - eats other consumers; "meat eater" Omnivore – eats both primary producers and consumers; Scavenger - feeds on organisms that recently died.




19 DECOMPOSERS Breakdown organic material and return it to environment for use by producers Heterotrophic organisms. Process called Decay Includes bacteria, mold, mushrooms Types Saprophytes - obtain their food from dead organisms or the waste products of living organisms Ex - molds, mushrooms Parasites - obtain their food from living organisms Ex - athlete's foot


21 Energy Flow Energy flows in various patterns in ecosystem. Total energy of one trophic level never flows to next level Food Chain - specific sequence where organisms obtain energy and organic materials from one another. Food Web - interconnected food chains formed due to the complex relationships


23 FOOD CHAIN Producer Primary Consumer Secondary Consumer Scavenger Grass Deer Puma Vulture

24 FOOD WEB Hawk Snake Lizard Mouse Bird Grasshopper Rabbit Grass

25 Ecological Pyramids Complexities of ecosystem are graphed to show the relationship between trophic levels Primary producer at the base with consumer levels above it. Common pyramid models Energy Pyramid Numbers Pyramid Biomass Pyramid

26 ENERGY PYRAMID Shows that energy is lost at each level Each organism in a given trophic level uses some of energy to carry on its own life functions. Always a loss of energy as heat in any system of energy transfer. Never inverted.


28 NUMBERS PYRAMID Shows number of organisms at each level Usually an increase in the size of the organisms with each level Normally producer organisms are most numerous; may be inverted Single tree may support thousands of insects and birds


30 BIOMASS PYRAMID Amount of matter that can be supported at each trophic level. Biomass is the total dry weight of organisms in the ecosystem.

31 BIOGEOCHEMICAL CYCLES Process where inorganic materials move from atmosphere or soil to living things and back Also called Nutrient Cycles. Water Cycle Nitrogen Cycle Oxygen-Carbon Cycle

32 WATER CYCLE Movement of water from atmosphere to the earth and back again. Precipitation - movement of water to earth from atmosphere Evaporation - way most water lost from earth's surface to atmosphere. Transpiration - loss water by green plants through their leaves.


34 NITROGEN CYCLE Process by which nitrogen passes from the atmosphere to organisms and back again Four major processes Nitrogen Fixation - bacteria convert nitrogen gas into ammonium compounds; live in roots of legumes Ammonification - bacteria break down nitrogen- containing amino acids from animal wastes and dead organisms to form ammonia compounds Nitrification - Bacteria oxidize ammonia compounds to produce nitrates and nitrites Denitrification - anaerobic bacteria break down nitrate releasing nitrogen gas back into the atmosphere


36 OXYGEN-CARBON CYCLE Involves processes of photosynthesis and respiration Photosynthesis removes CO 2 from atmosphere and fixes it as glucose and releases O 2 Respiration removes O 2 from atmosphere and CO 2 is released. Normally processes balance each other. Levels of O 2 and CO 2 remain fairly constant


38 Since about 1850's fossil fuels consumption has increased Fossil fuels represent stored carbon compounds Combustion of the fuels has increased the CO 2 level of the atmosphere. Increased levels of CO 2 increase the atmosphere’s ability to trap heat. Greenhouse Effect - an increase in atmospheric temperature due to heat being trapped by the atmosphere. Can change climates and habitats Should be called Global Warming


40 Terrestrial Biomes BIOME Large area identified by the presence of characteristic plants and animals. Commonly identified by dominant plant life. Don't have definite boundaries Usually have characteristic rainfall and temperatures.

41 POLAR BIOMES Surround North and South poles Receive very little precipitation - fresh water scarce Soil is sparse, low in nutrients, frozen much of the year Temperature range - -40o C to 4o C Receive virtually no sunlight for half the year. Arctic Polar Biome Lies over Arctic Ocean Plants - Some flowering plants, mosses, lichens, Animals - Gulls, Walruses, polar bears along Arctic coast. Antarctic Polar Biome Lies over landmass of the Antarctic continent. Plants - lichens, mosses, 3 types of flowering plants Animals - small insects, seals, whales, penguins.

42 TUNDRA Treeless biome blanketed by snow in winter that forms continuous belt across northern North America, Europe, and Asia Tundralike regions may also exist on mountains above treeline Highest point at which trees grow. Characterized by a Permafrost Surface soil thawed for only about 8 weeks During thaw patchwork of shallow pond, bogs, and soggy soil Climate - cold and dry Plants - mosses, lichens, dwarf woody plants – No trees Animals - Insects, ducks, geese, predatory birds, musk ox, caribou, lemmings, and weasels


44 CONIFEROUS FOREST Biome dominated by conifers Long, cold winters and short cool summers. Nutrient poor soils; usually acidic. Animals - moose, bear, lynx Northern parts of Europe, Asia, and North America Three subdivisions Taiga Coniferous Belt Southern Pine Forests


46 DECIDUOUS FOREST Characterized by trees that lose their leaves in the fall. Definite seasons; temperate region Stretch across eastern U.S., much of Europe, part of Asia, South America, Africa, and Australia Precipitation evenly distributed over the year; Rainfall - 75 to 125 cm per year; moderately rich soil Dominant trees - birch, beech, maple, oak, hickory, elm, sycamore, willow, and cottonwood. Animals - white-tailed deer, black bear, raccoons, squirrels, hundreds of bird species


48 GRASSLAND Dominated by grasses Cover about one-fourth of earth's land surface Found in variety of temperature ranges Rainfall - 25 to 75 cm per year. Animals - bison, antelope, elephants, giraffes, kangaroos Soil usually very rich Various names Prairie - North America Steppes - Asia Pampas - South America Veldt - Africa


50 DESERT Dry areas - rainfall averages <25 cm per year Organisms are adapted to harsh conditions Plants have deep root systems, some store water, thickened stems and branches. Temperatures may vary greatly - hot days/cold nights Plants - cactus, sagebrush, creosote, some annuals. Animals - camel, jackrabbits, many reptiles, scorpions, Kangaroo rats


52 RAIN FORESTS TROPICAL RAIN FOREST Found near equator Abundant rainfall and sunlight - 200 to 225 cm per year. Supports many plant species - growth rate is rapid Soil is thin, moist, very low in nutrients. Removal of vegetation results in loss of soil Animals - insects, parrots, toucans, apes, monkeys, predatory cats TEMPERATE RAIN FOREST Moderate temperatures and high humidity West coast of North America from California to Alaska. Plants - redwood, Sitka spruce Animals - deer, elk, rodents



55 Aquatic Biomes MARINE BIOME Earth's oceans and associated areas Divided into 3 areas Ocean Intertidal zones Estuaries

56 OCEAN Covers 70% of earth Water contains about 3.5% salt Divided into two zones Pelagic Zone - open ocean Neritic Zone - out over continental shelf Oceanic Zone - over deep water of open sea. Benthic Zone - ocean bottom Divided according to light penetration Photic Zone - light penetrates Aphotic Zone - light doesn't penetrate


58 INTERTIDAL ZONES Area between high tide and low tide lines Organisms adapted to periodic air exposure Animals - crabs, clams, mussels, shorebirds.


60 ESTUARY Biome between freshwater and marine biomes Region where rivers/streams flow into the sea Subject to the oceanic tides Tidewater regions Organisms subject to changing environment. Animals - shrimp, oysters, clams, crabs, many fish, numerous birds.


62 FRESHWATER BIOME Characterized by low levels of dissolved salts Separated into 2 categories Lakes and Ponds Eutrophic Lakes - rich in organic matter /vegetation Oligotrophic Lakes - water with little organic matter. Rivers and Streams Bodies of water that flows down a slope Gradient is key abiotic factor Steep gradient - fast flow Low gradient - slow flow. Animals - fish, muskrats, otters, ducks, loons, numerous insects


64 Biotic Relationships COMPETITION Use or defense of a resource by one individual that reduces the availability of that resource to other individuals May complete for habitat or food Individuals in nature that don't retain access to prime habitat may be less successful in their struggle to survive and reproduce. Types Intraspecific Competition Interspecific Competition

65 INTRASPECIFIC COMPETITION Competition between members of same species Example - lions fighting to mate Individuals best adapted, survive and pass genetic material on at a greater rate. Driving force of evolution.

66 INTERSPECIFIC COMPETITION Competition between organisms of different species. Not as intense - members aren't competing for exactly the same materials Deer and rabbits grazing in an open meadow Competitive Exclusion Principle When 2 or more species compete for the very same resource, all but one will eventually fail 2 competitors can’t coexist on same limiting resource.

67 PREDATION Consumer hunts/feeds on another consumer. Predator - the hunter Prey - the hunted. Helps maintain an ecological balance or natural equilibrium in an ecosystem Predator and prey numbers graphs show max of prey followed by a max of predators. Snowshoe hare & lynx populations


69 SYMBIOSIS Biological relationship where 2 dissimilar organisms live together closely Interaction affects survival of one or both Types Parasitism Commensalism Mutualism

70 PARASITISM Symbiotic relationship where one organism obtains nutrition from another organism One benefits; other harmed Parasite - organism that benefits Host - organism that provides food; harmed. Good parasite doesn’t kill its host quickly. Ex - athlete's foot; ticks/mites; tapeworms


72 COMMENSALISM Form of symbiosis in which one organism benefits and the other neither benefits nor suffers harm Host is not harmed. Epiphytes - type of plant that grows on other plants; Orchids - orchid roots absorb air moisture, tree - high place for light. Barnacles on whales - barnacle benefits, steady food supply, whale not harmed.


74 MUTUALISM Symbiosis where both organisms benefit Bacteria in digestive tract of cattle Lichens Termites


76 Rhythmic Patterns Activities of many organisms tied to cycles of time. Rhythmic because they are regular and predictable. Adaptation that often limits competition Allow species to occupy the same habitat but to utilize resources at different times. Owls hunt mice - night Hawks hunt mice - day. Rhythmic cycles may be linked to variations in: Length of daylight Temperature Hormone levels

77 CIRCADIAN RHYTHMS Cycles occurs about every 24 hours; means "about a day" So-called biological clock; not sure where control center is located Have investigated whether human rhythms are controlled by sunlight, other physical factors, or some internal physiological mechanisms Humans keeps regular cycle between 22 - 26 hours in dark rooms. Nocturnal - active mainly at night Diurnal - active during the day Examples Morning Glories Marine zooplankton Humans


79 ANNUAL RHYTHMS Any physiological/behavioral pattern that recurs yearly Many reproductive cycles tied to annual rhythms Female bears give birth during winter Nesting of ducks in spring /summer Production of flowers/pollen at particular time Seasonal Changes Hibernation Estivation

80 HIBERNATION State of severely reduced physiological activity in winter. Allows active creatures to survive when extremely cold and food scarce. Breathing slow/irregular, blood pressure drops, and body temperature drops. Animals that hibernate Bats, chipmunks, woodchucks, many reptiles and amphibians. Some animals go into a deep sleep, not hibernating Bears, opossums, skunks

81 ESTIVATION Annual rhythm characterized by severely reduced physiological activity in summer. Escape from hot temperatures/dry conditions May last for days, weeks, or months Animal usually buries self in mud. Animals that estivate Frogs, toads, box turtles, some mice

82 MIGRATORY RHYTHMS Seasonal movement of some species from one community or biome to another called Migration Allows use of nutrients, habitats, and climatic conditions only available during a particular season. Some movements may cover long distances Arctic tern breeds in N. Atlantic; migrates to Antarctic Monarch Butterflies from Canada/northern U.S. to Mexico Mountain dwelling animals may migrate vertically Bighorn sheep/elk move up slopes of in summer and down in winter.

83 TIDAL or LUNAR RHYTHMS Tides due to gravitational pull of moon and sun on earth’s oceans High tides - about every 12.5 hours.- low tide in between. Activities of intertidal organisms affected by the rise/fall of tides. Barnacles - shell closed during low tide to prevent drying. Many fish feed in tidal pools at high tide, leave as tide recedes Grunion Reproduction - with high tides of spring/summer Male fish come ashore, followed by females Eggs laid/fertilized/buried in sand Fry carried to sea about 10 days later.

84 Succession Gradual, sequential replacement of populations in an area by other populations. Organisms change their environment in ways that make it less favorable to themselves and more favorable for other organisms Changes in abiotic factors may lead to changes in the ecosystem


86 Stages of Succession Pioneering Stage Pioneer Species - first species to colonize a new habitat Stabilize and enrich soil. Serial or Developmental Stage Intermediate communities of area. Crowd out pioneer species, shade out smaller species; further stabilize and enrich soil Climax Community Community that remains stable if the area is undisturbed. Abiotic factors usually determine climax community


88 Types of Succession PRIMARY SUCCESSION Sequential replacement of populations in an area that has not previously supported life. Usually occurs in areas where bare rock has been exposed. Lichens are the pioneer organisms Helps begin soil formation As soil established larger plants may inhabit the area. Eventually a climax community will be reached. Process is very slow - may require hundreds of years.


90 Types of Succession SECONDARY SUCCESSION Community development in an area where a prior community was removed. Usually associated with some type of natural disaster. Soil still present - grasses usually pioneer species. Re-establishes the original community. Progresses more rapidly than primary succession Usually requires about a hundred years. Old Field Succession Population replaced on abandoned farm fields.


92 LAKE SUCCESSION Transformation from crystal clear bodies of water to dry land Involves process of Eutrophication Increase in nutrients in an environment. Young lakes called Oligotrophic low in nutrients relatively few organisms As nutrients and silt flows into the lake the water becomes murkier. Sediment accumulates around roots of cattails and rushes at edge of lake Lake Biomass increases Aquatic arthropods and fish populate the lake. Sediment begins to fill lake, becoming eutrophic Lake becomes filled with rich sediment it becomes a marsh, then a swamp, and finally dry land Can proceed through stages to become dense forest.


94 Population Changes (Growth) Growth of a population - due to births and immigration Immigration - moving of individuals/organism to area. Population increase in size. Decrease of a population - due to deaths and emigration. Emigration - moving of organisms/individuals from area. Size of the population decreases. Change in population size expressed as mathematical formula: Change = (Births + Immigrants) - (Deaths + Emigrants) Climax communities, birth and death rates remain about same Developing communities populations may change in size

95 Population Growth An increase in a population POPULATION GROWTH RATE Change in the number of individuals in a population over time: Growth Rate = Change in Number of Individuals / time BIOTIC POTENTIAL of a population Rate a population grows if all survive and reproduce at maximum Biotic potential usually never reached - limiting factors. Food supply Available space Predation Accumulation of wastes CARRYING CAPACITY - population size environment can support.

96 GROWTH CURVES A graph showing the number of individuals in a population over time Types of Growth Curves J - SHAPED CURVE S - SHAPED CURVE

97 J - SHAPED CURVE LAG PHASE - period when there is little or no increase in a population Limited number of females reproducing EXPONENTIAL PHASE - population increases so rapidly that number of individuals doubles in a specific time interval Doubles in shorter periods of time


99 S - SHAPED CURVE Exhibits lag & exponential phases Doesn't increase as rapidly. Leveling off represents a period of relative stability after the lag and exponential phases. Leveling gives indication of carrying capacity Stabilization Phase – remains level May get curve that declines after leveling off Associated with bacterial/fungal cultures.


101 Limits to Growth POPULATION DENSITY Number of individuals per unit of area Density = Individuals / Area Low density may result in population dying High population density Protects individuals in the population

102 DENSITY-DEPENDENT FACTORS Factors that affect populations in different ways depending on population density Usually biotic Food Availability controls population size Factors include availability of space and light, disease, number of predators, and parasitism

103 DENSITY-INDEPENDENT FACTORS Factors affect populations regardless of population density. Usually abiotic Temperature, rainfall, wind speed, etc.

104 Human Populations Survival rate of humans has increased due to domestication of crops and animals Provided humans with stable food supply.

105 Human Population Growth From about 6000 B.C. to A.D. 1800 Number of humans in world increased steadily Lag phase of J - shaped curve About mid 1800's Dramatic increases - entered exponential phase Increased food production, rise of industry, and better medicine Life expectancy became longer. Eventually will be limited by same density dependent factors that limit other populations.


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