* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download document 8133092
Survey
Document related concepts
Ecological fitting wikipedia , lookup
Restoration ecology wikipedia , lookup
Biogeography wikipedia , lookup
Storage effect wikipedia , lookup
Ecosystem services wikipedia , lookup
Biodiversity action plan wikipedia , lookup
Source–sink dynamics wikipedia , lookup
Renewable resource wikipedia , lookup
Human population planning wikipedia , lookup
History of wildlife tracking technology wikipedia , lookup
Maximum sustainable yield wikipedia , lookup
Decline in amphibian populations wikipedia , lookup
Transcript
Ecology Environmental Science Levels of Organization Species A group of similar organisms that are able to interbreed Population All the members of a species living in one area at one time Community All the populations of organisms living in one area at one time Ecosystem A community and its physical (non-living) environment Ecological Interactions There are two types of factors within an ecosystem. Abiotic - Non-living factors Biotic - Living factors Both can control what organisms are found where. Ecological Interactions The cycling of energy and compounds link all organisms within an ecosystem. Affecting one organism in the web, can affect organisms above, below, and beside it in the system. DQ - Discuss an example where changing one thing has effects on many others. Energy in Ecosystems First Law of Thermodynamics - Energy cannot by created nor destroyed. Second Law of Thermodynamics - With each energy transfer in a system less energy is available. What does this mean? DQ - Where does the energy go? Energy in Ecosystems DQ - Where does energy come from in eco systems? Sun is major source for most but not all! Photosynthesis - Using light to make energy for the organism Chemosynthesis - using chemicals to make energy for the organism DQ - How does energy get through the rest of the ecosystem? Energy in Ecosystems Energy is transferred by organisms consuming other organisms The food chain 1 min ACTIVTY - Come up with a food chain There are several different levels to a food chain Producers Primary Consumers Secondary Consumers Tertiary Consumers Quaternary Consumers Decomposers Trophic Levels Each of the levels is called a trophic level The amount of energy available decreases as you move up each level 2nd law of thermodynamics DQ - Why are there so many more insects than tigers in the world? Law of 10% - only 10% of energy is passed to next level. Trophic Levels Can be expressed in energy pyramids Page 64 Trophic Levels Example problem - If the producer started with 25,000 cal, how many would the primary consumer obtain? 2,500 cal Tertiary consumer? 25 cal DQ - What does this mean for humans? Food Web A food chain is useful in determining trophic levels, but not in showing interdependence. For that we use food web This shows us several organisms within an ecosystem. Shows that organisms are not always the same level in every chain Food Web Assignment Create an example food web with at least 10 individual organisms. Then explain, if one organism were removed from the web how would it effect the rest of the organisms. Other factors to interactions DQ - What other types of interactions are there within an ecosystem? Competition Symbiotic Relationships Commensalism, Mutualism, Parasitism Predator-Prey Keystone Species Spatial Distribution Mating Activity Divide into groups of three In your groups you will have one of the relationships listed on the previous slide to research and will present to the rest of the class. Populations Individuals of a species live in populations Population – consists of all the individuals of a species that live together in one place at one time What is the reason for a definition like this? So scientists can talk about all sorts of populations with similar terms Examples of populations? Populations Human population has tripled since 1930 DQ - What could stop a population from growing? Limited resources is #1 reason As well as other factors Thing to remember: Populations are constantly changing What do we mean by this? Populations Every population has features that help determine it’s future: 1. Population size 2. Population density 3. Dispersion Each one can effect a populations in different ways. Populations Population size – the number of individuals in a population DQ - How could this determine the future? Small populations are affected by disturbances more than large populations Inbreeding is a big problem with a small population DQ - Why would this be? Inbreeding causes the population to be genetically identical, meaning one disease can wipe out entire population Estimating Population Within ecosystems, scientists have to have an idea of the population of an organism. This helps them understand how organisms will interact DQ - How do they do that? Most popular is the capture-recapture method Uses a formula: Marked organism recaptured = total marked Total organisms captured (rnd 2) pop. size Activity We are going to demonstrate this method and practice using the formula Toothpick estimation lab Individual lab Populations Population Density – the number of individuals that live in a given area DQ - How is this different than population? DQ - How would this effect a population? If individuals are very spread out, they may rarely meet, meaning reproduction is sparse DQ - What might happen if too close together? Populations Dispersion – the way the individuals of the population are arranged in space There are three main patterns of dispersion: Clumped Random Uniform DQ - How would this effect the population? Populations Scientist use models to predict how populations will grow Three types of growth rate 1. Stage I model Rate of growth = birthrate – death rate 2. Exponential growth curve Also called the stage II model Complicated equation Set interval of reproduction (example – bacteria) Populations The third type of Growth Rate: 3. Logistic Growth Also called Stage III model Another complicated equation Takes into account the limited amount of resources Best one for nature Can cause frequency of changes within population Carrying Capacity – population size that the environment can sustain. Populations Real populations exhibit a range of growth patterns DQ - Why might this be? Many times organisms overshoot then die off DQ - What would this look like on a graph? Populations Population pyramids: Population Changes Populations have factors that help determine life expectancy and survivorship. Life expectancy - the probable number of years of survival for an individual Survivorship - % of a population that survives to a certain age. Environmental resistance environmental factors that cause the carrying capacity DQ - What are some of these factors? Factors that influence populations: Predation Amount of resources Human interaction Gene flow Disease Natural disasters Others Survivorship curves 4 main types of survivorship Each curve represents different types death rates. Each curve has several animals that can be used for examples No fancy names just Type 1,2,3, and 4 Easier to identify with the animals that follow the curve. Pg. 123 in book QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Survivorship Curves Type 1 - What is going on? Most organisms survive to old age, then die off quickly Example organisms? Humans, most top consumers in an ecosystem Type 2 - What is going on? Organisms die off at a pretty steady rate Death not as related to age Examples? Many birds, including seagulls and hawks Survivorship curves Type 3 - What is going on? High young mortality rate but if they survive, live very long lives Examples? Fish, trees, most animals at the bottom of the food chain Type 4 - What is going on? High mortality before maturity and after reproductive age Examples? Humans (developing), deer, rabbits Population Changes Populations have trait frequencies These frequencies will stay the same as long as outside factors do not influence the population What is wrong with this? There are always outside factors that influence populations!!!! What are some of these factors? Population Changes Another factor that can effect how a population changes: Natural selection The organism that is best fit for its environment will eventually dominate the population frequencies Survival of the fittest Occurs when there is variation in a population Population Changes Types of Selection: Directional selection – the form of selection that causes the frequency of a particular trait to move in one direction Causes the trait to become more or less common Examples? Population Changes Types of Selection: Stabilizing selection – distribution of traits becomes narrower Eliminates the extremes of the trait Examples? More common in nature Assignment Pg 129 PQ - 2,6,9 CT - 2, 4 Bring a tube of M&M minis Quiz tomorrow Activity Hunting M&Ms on Fabric Ecosystem Health Several ways to judge how healthy an ecosystem is. DQ - What do you think those are? Productivity Biodiversity Cycling of materials DQ - How do each of these affect how healthy the ecosystem is? Biodiversity What is it? the number of different species living within an eco-system High Biodiversity = ?? Better health Plays a HUGE role in determining the complexity and resiliency of a system What are these? Biodiversity Complexity - # of species at each trophic level High complexity = Better health DQ - Why? Resiliency - Resistance to Disturbances There are always disturbances so systems need a high resiliency. Productivity What is it? The rate of biomass production Why would this be a big deal? DQ - Relates directly to the amount of energy available to the system. More productivity means more of the suns energy is being converted. DQ - Examples of consistently productive ecosystems? Forests, coral reefs, estuaries, agricultural land. Cycling of materials There is a cycle of materials within an ecosystem The four most important ones: carbon, nitrogen, phosphorus and water If something throws off the cycle, the eco-system loses materials, and becomes weaker Eco-systems Water cycle: Eco-systems Carbon Cycle: Eco-systems Nitrogen cycle Changing Ecosystems Sometimes the disturbances can destroy an ecosystem or part of it. Sometimes this is beneficial to many species Forest Fires, Volcanoes, floods How can it be beneficial? Brings nutrients to the system, and breaks up the dominant species Cause the community to change Communities changing As communities changes new types of species can take over This is called succession Two Types: Primary succession - land that is bare of soil. (nothing lived there before) Secondary succession - existing community is disturbed and a new one develops. Succession As time goes on, the system becomes more complicated. Pioneer species - first colonists Can survive on few resources Lichens, mosses, microbes They create organic material and nutrients for later species Ends with Climax Community that lasts until the next large disturbance