1 / 53

Ecology

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

sophia-rosales
Download Presentation

Ecology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ecology Environmental Science

  2. 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

  3. 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.

  4. 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.

  5. 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?

  6. 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?

  7. 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

  8. 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.

  9. Trophic Levels • Can be expressed in energy pyramids • Page 64

  10. 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?

  11. 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

  12. Food Web

  13. 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.

  14. 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

  15. 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.

  16. 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?

  17. 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?

  18. 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.

  19. 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

  20. 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

  21. Activity • We are going to demonstrate this method and practice using the formula • Toothpick estimation lab • Individual lab

  22. 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?

  23. 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?

  24. 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)

  25. 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.

  26. 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?

  27. Populations • Population pyramids:

  28. 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

  29. DQ - What are some of these factors? • Factors that influence populations: • Predation • Amount of resources • Human interaction • Gene flow • Disease • Natural disasters • Others

  30. 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

  31. 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

  32. 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

  33. 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?

  34. 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

  35. 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?

  36. Population Changes • Types of Selection: • Stabilizing selection – distribution of traits becomes narrower • Eliminates the extremes of the trait • Examples? • More common in nature

  37. Assignment • Pg 129 PQ - 2,6,9 CT - 2, 4 • Bring a tube of M&M minis • Quiz tomorrow

  38. Activity • Hunting M&Ms on Fabric

  39. 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?

  40. 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?

  41. 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.

  42. 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.

  43. 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

  44. Eco-systems • Water cycle:

  45. Eco-systems Carbon Cycle:

  46. Eco-systems • Nitrogen cycle

  47. 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

More Related