Presentation on theme: "Ecology Unit Chapter 2: Principles of Ecology"— Presentation transcript:
1Ecology Unit Chapter 2: Principles of Ecology Chapter 3: Communities, Biomes and EcosystemsChapter 4: Population EcologyChapter 5: Biodiversity and Conservation
22.1 organisms and their relationships Ecology – scientific study of all the relationships that occur between organisms and their environmentThe word ecology was first introduced in 1866 by a German biologist named Ernst Haeckel.
3Biotic and abiotic factors Biotic factors – living factors in an organism’s environmentExamples - ?Abiotic factors – nonliving factors in an organism’s environmentExamples – temperature, air currents, water currents, sunlight, soil, rainfall
4Levels of organization Biosphere – portion of Earth that supports lifeEcologists look at smaller portions of the biosphere when studying ecological relationshipsinteractive levels of org (look at p 37)BiomeEcosystemCommunityPopulationOrganism
5Ecosystem interactions Habitat – an area where an organism livesNiche – role or position that an organism has in its environment.An organism’s niche describes how it meets its needs for food, shelter and reproduction
7Community Interactions Competition – more than one organism uses a resource at the same timeResources are necessary for life and might include food, water, space, light, and matesPredation – the act of one organism consuming another
8Mutualism – relationship between two or more organisms that live closely together and benefit from each otherCommensalism – relationship in which one organism benefits and the other organism is neither helped nor harmedParasitism – relationship in which one organism benefits at the expense of another organism
92.2 Flow of energy Organisms differ in how they obtain energy Everything that organisms do in ecosystems requires energy.Where do organisms get their energy?From the Sun (of course)!!
10Autotroph – an organism that collects energy from sunlight to produce food Autotrophs are also called producersAutotrophs capture energy from the Sun, making it available for all members of an ecosystemHeterotroph – an organism that gets its energy by consuming other organismsHeterotrophs are also called consumersHerbivores eat only plantsCarnivores prey on other heterotrophs for foodOmnivores eat both plants and animalsDetritivores eat dead, decaying materialDecomposers break down dead material by releasing digestive enzymes
11Models of energy flowEcologists use food chains and food webs to model the energy flow through an ecosystemFood chain – a single, straight-line path of energy that involves only 4-5 organismsFood web - a bunch of food chains put together for a given habitat.Each step in a food chain or food web is called a trophic levelAutotrophs make up the first trophic levelHeterotrophs make up the remaining levels
13Loss of energy in a food chain When an organism eats, almost half of the energy in the food is lost to the environment as heat.The amount of useful energy available to do work decreases as energy passes through the ecosystemRule of 10Only 1/10 (10%) of energy is used by an organism when it eatsThe other 90% is lost to the environment
14Energy PyramidsAn energy pyramid is a diagram that shows 3- 4 trophic levelsThe size of each block is determined by the amount of energy available
152.3 Cycling materialsThere are 4 different cycles that we find in the environmentWater, carbon, phosphorus, and nitrogenA cycle is a pathway that describes how a chemical movesA substance enters a living organismThe substance may stay in the organism for some timeThat same substance eventually leaves the organism and returns to the environment
16The water cycle is very important to living things!! Freshwater constitutes only about 3% of all water on EarthWater available for living organisms is about 31% of all freshwater69 % of all freshwater is found in ice caps and glaciersEven ocean-dwelling organisms rely on freshwater flowing to oceans to prevent high salt concentrations inside their body.
17Steps:Evaporation from bodies of water and/or transpiration from plantsCondensation in the form of cloudsPrecipitation that falls as snow, rain, sleet, hail, etc.Some precipitation is absorbed by the soil and stored as ground water.Refer to page 46interactive water cycle
18The carbon cycleCarbon dioxide is absorbed by plants to make their own food and produce oxygenCarbon dioxide is released into the atmosphere in two ways:Respiration-breathingCombustion-burning of fossil fuelsWhat is a fossil fuel?List several types of fossil fuelsinteractive carbon cycle
203.1 Community ecologyCommunity – a group of interacting populations that occupy the same area at the same timeLimiting factor – any abiotic or biotic factor that restricts the numbers, reproduction or distribution of organisms in a communityExamples include: sunlight, climate, water, temperature, nutrients, fire, soil, spaceIf the environment of the community changes, plants and animals have to:Adapt in order to surviveMigrate to a place that has resources
22Succession Ecosystems are constantly changing A tree falls in the forestA forest fire wipes out a large communityEcological succession – the change in an ecosystem that happens when one community replaces another as a result of changing abiotic and biotic factors
23Two types of succession Primary successionA change in the environment that allows an area of land to support living things where it never did beforeExamples: melting glaciers, volcanoSecondary successionA major (sometimes drastic) change in the environment that destroys much of what was living but allows for growth years later.Examples: tornado, hurricane, forest fire, flood, windstorm
263.2 Terrestrial biomesWeather – condition of the atmosphere at a specific place and time.Important elements of weather:TemperatureMost organisms live best within a certain range of temperaturesThere are three major climate zones: tropical, temperate and arcticMoistureAll organisms require water, so they must find a place to live that satisfies their needs.Elevation and ocean currentsVisualizing Global Effects on Climate (p 67)
27Be familiar with… Major land biomes pp 68-72 Mountains p 72 Polar regions p 73Freshwater ecosystems pp 74-77Wetlands p 78Estuaries p 78Marine ecosystems p 79-81
284.1 Population dynamics All species occur in groups called populations Populations are characterized by:Population density – the number of organisms in a given areaSpatial distribution – the pattern of spacing of a populationThree types: uniform, clumped, randomVisualizing Population Characteristics (p 93)Population ranges
29Factors that limit Populations Density-independent factors – any factor in the environment that does not depend on the number of members in a populationExamples: drought, flooding, extreme heat or cold, tornadoes, hurricanesDensity-dependent factors – any factor in the environment that depends on the number of members in the populationExamples: predation, disease, parasites, and competition (see next slide)
31Population growth rate PGR – how fast a given population growsDependent on birth rate and death rateIf a population has more births then deaths, the population is ______________If a population experiences more deaths then births, the population is ____________If a population has an equal number of births to deaths, the population is _____________Also dependent on emigration and immigrationEmigration – describes the number of people moving away from a populationImmigration – describes the number of people moving into a population
32Population growth curves Exponential growth curve (j-curve)Occurs when the growth rate is proportional to the size of the populationAll populations grow exponentially until some limiting factor slows the population’s growth.Logistic growth curve (s-curve)Occurs when the population’s growth slows or stops following exponential growth when the population reaches it’s carrying capacity.Carrying capacity – the maximum number of individuals in a species that an environment can support for the long term.
354.2 Human Population 1804 – estimated 1 billion people Demography – the study of human population size, density, distribution, movement, birth rate and death rate.1804 – estimated 1 billion people1999 – 6 billion people2011 – 7 billion people2020 – projected to be 8 billion people
36This looks like a J-curve, right This looks like a J-curve, right? At what point to we reach carrying capacity?
37Why are people living longer? Agriculture has improved, allowing more people to be fed by large crops (corn, soybeans, wheat, etc).The breeding of animals (cows, pigs, chickens, etc) has increased food supplies.Technology has given people more information at their fingertips.Medications and vaccines have increased a person’s chance for survival by reducing the number of deaths from parasites and disease.Improvements in shelter have helped people survive major weather disasters.
38Population pyramidsPopulation pyramids show the age structure of a given population.The age structure is the number of males and females in each of three categories:Pre-reproductive:ages 0-19Reproductive:ages 20-44Post-reproductive:agespopulation pyramidanimation
39Human carrying capacity Many scientists suggest that human population growth needs to be reduced.In many countries, voluntary population control is occurring.In other countries, “mandatory” population control is occurring.If human population continues to grow:areas become overcrowded and disease and starvation will occurnatural resources become scarce (p 105)
405.1 BiodiversityBiodiversity is the variety of life in an area that is determined by the number of different species in that area.The importance of biodiversityEconomic valueHumans depend on plants and animals for food, clothing, energy, and shelterMedical/scientific valueMedicines are derived from plants and animalsThe Madagascar periwinkle produces and extract that has been used with leukemia patients to increase survival (p 119)Aesthetic valuePlants and animals give us a better appreciation
435.2 Threats to Biodiversity Scientists believe we are witnessing a period of mass extinction—an event in which a large percentage of all living species become extinct in a short period of time.The current high rate of extinction is due to the activities of one species – HUMANS.Humans are changing conditions on Earth so fast that it doesn’t allow other organisms to adapt and survive.
44OverexploitationTaking more individuals from a population than the species can replace.Bison were hunted to near extinction for their meat and furPassenger pigeons went extinct in the early 1900s due to overhunting and urbanizationThe ocelot is hunted for the high value of its furRhinos are in danger of becoming extinct because of poachers who kill them for the horns on their head
45Habitat lossHumans are clearing areas of land for housing and are replacing native plants with food crops.The tropical rainforests contain much of the world’s biodiversity. Removal of the forest will cause many species to become extinct.Natural disasterscan causedisruption ofhabitats which inturn destroy foodwebs.
46PollutionPollution changes the composition of air, soil, and water for all animals.There are lots of toxic substances put into the air or dumped into the water or soil. Many of these substances accumulate in the tissues of living organisms.Biological magnification describes the increasing concentration of toxic substances in organisms as trophic levels increase in food webs.More and more news articles talk about mercury levels in fish. The more mercury in the water, the more mercury in fish tissue, the more mercury we consume when we eat fish.
47Introduced speciesNonnative species that are either intentionally or unintentionally transported to a new habitat are a threat to native species living in that area.Lamprey of the Great LakesAsian long-horned beetleEmerald ash borer
48Acid PrecipitationWhen fossil fuels are burned, compounds called sulfur dioxide and nitrogen oxide are released into the atmosphere. These compounds react with water and form acids that fall back to Earth in the form of precipitation.More heavily populated areas have heavier amounts of acid rain.Aquatic animals and plants slowly die from acidic levels in the water, forests are burned, animals are forced from their homes.
49EutrophicationOccurs when fertilizers, animal waste, and sewage rich in nitrogen and phosphorus flow into waterways, causing algae growth.The algae use all the oxygen in the water and suffocate plants and other aquatic species.
50Protecting the Ozone Layer Ozone is a compound made up of 3 oxygen moleculesThe ozone layer is important because it protects living things from ultraviolet (UV) radiationThe ozone concentration is much lower over AntarcticaWhat destroys ozone?CFCs = cloroflourocarbonsfound in coolants of old refrigerators and air conditionersalso found in aerosol chemicals of spray cansVOCs = volatile organic compoundsfound in paints and varnishes, glue, caulk, air fresheners, cleaning and disinfecting products
51Controlling Greenhouse gases Human activity causes gases to be released into the atmosphere. These gases trap solar energy and help to insulate the Earth just like a greenhouse traps heat from the Sun.
52Greenhouse gases include: Water vapor, carbon dioxide, and methaneBecause humans still burn fossil fuels, carbon dioxide levels get higher and higher.When water vapor and carbon dioxide are mixed in the atmosphere they trap the solar energy and contribute to the Earth’s rising temperature.All of this trapped heat energy causes changes to weather patterns, making storms more severe across the globe.Some of this trapped heat also causes the ice to melt (glaciers, ice sheets) at the north and south poles.
53Protecting Fresh water Freshwater is in short supply because humans pollute this very important resourceHow can you conserve water in your home?
54The total usable freshwater supply for ecosystems and humans is less than 1 percent of all freshwater resources.By 2025, 1.8 million people will be living in countries or regions with absolute water scarcity, and two-thirds of the world population could be under stress conditions.
55The UN suggests that each person needs liters of safe freshwater a day to ensure their basic needs for drinking, cooking and cleaning.More than one in six people worldwide million - don't have access to this amount of safe freshwater.Globally, diarrhea is the leading cause of illness and death, and 88 percent of diarrheal deaths are due to a lack of access to sanitation facilities.Today 2.5 billion people, including almost one billion children, live without even basic sanitation.Every 20 seconds, a child dies as a result of poor sanitation. That's 1.5 million preventable deaths each year.
56The daily drinking water requirement per person is 2-4 liters, but it takes 2000 to 4000 liters of water to produce one person's daily food.In 2007, the estimated number of undernourished people worldwide was 923 million.By 2050, the world's water will have to support the agricultural systems that will feed an additional 2.7 billion people.Every day, 2 million tons of human waste are disposed of in waterways.In developing countries, 70 percent of industrial wastes are dumped untreated into waters where they pollute the usable water supply.
575.3 Conserving biodiversity As population increases, the need for natural resources also increases, but usually at the expense of harming other species.Visualizing biodiversity hot spotsNonrenewable resources are found in limited amounts and must be used carefully.Fossil fuels, minerals, waterRenewable resources have an endless supplySolar, windMore people need to live sustainablyReduce the amount of resources consumedRecycle resources that can be recycledTake resources from an ecosystem responsibly