ecology n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Ecology PowerPoint Presentation
Download Presentation
Ecology

Loading in 2 Seconds...

play fullscreen
1 / 33

Ecology - PowerPoint PPT Presentation


  • 105 Views
  • Uploaded on

Ecology. Part 4. Populations Part 5. Communities Part 6. Biodiversity and Conservation. Population Ecology: Population Characteristics. Population Characteristics. Population Density: The number of organisms per unit area Spatial Distribution:

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Ecology' - ojal


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
ecology

Ecology

Part 4. Populations

Part 5. Communities

Part 6. Biodiversity and Conservation

population characteristics

Population Ecology: Population Characteristics

Population Characteristics
  • Population Density:
    • The number of organisms per unit area
  • Spatial Distribution:
    • Dispersion: The pattern of spacing a population within an area
    • 3 main types of dispersion
      • Clumped
      • Uniform
      • Random
    • The primary cause of dispersion is resource availability
population limiting factors

Population Ecology: Population Characteristics

Population Limiting Factors
  • Population growth rate
    • How fast a given population grows
    • Factors that influence this are:
      • Natality (____ rate)
      • Mortality (_____ rate)
      • Emigration (the number of individuals moving _________ a population)
      • Immigration (the number of individuals _________ a population)

birth

death

away from

moving to

population limiting factors1

Population Ecology: Density-independent factors

Population Limiting Factors
  • Density-independent factors
    • Factors that limit population size, regardless of population density.
    • These are usually abiotic factors
    • They include natural phenomena, such as weather events
      • Drought, flooding, extreme heat or cold, tornadoes, hurricanes, fires, etc.
population limiting factors2

Population Ecology: Density-dependent factors

Population Limiting Factors
  • Density-dependent factors
    • Any factor in the environment that depends on the number of members in a population per unit area
    • Usually biotic factors
    • These include
      • Predation
      • Disease
      • Parasites
      • Competition
understanding exponentials
Understanding Exponentials

Population Ecology: Population Growth Rate

  • Put your pens down for a minute & think about this:
    • An employer offers you two equal jobs for one hour each day for fourteen days.
    • The first pays $10 an hour.
    • The second pays only 1 cent a day, but the rate doubles each day.
    • Which job will you accept?
understanding exponentials1

Population Ecology: Population Growth Rate

Understanding Exponentials

Now, how much would your employer owe you if you stayed at this job for another 2 weeks?

Job 2 lags for a long time before exponential growth kicks in!

What would happen if this type of growth took place within a population?

population limiting factors3

Population Ecology: Population Growth Rate

Population Limiting Factors
  • Population growth models
    • Exponential growth model
      • Also called geometric growth or J-shaped growth.
      • First growth phase is slow and called the lag phase
      • Second growth phase is rapid and called the exponential growth phase
      • Bacteria can grow at this rate, so why aren’t we up to our ears in bacterial cells?
population limiting factors4
Population Limiting Factors

Population Ecology: Population Growth Rate

  • Population growth models
    • Limits to exponential growth
      • Population Density (the number of individuals per unit of land area or water volume) increases as well
      • Competition follows as nutrients and resources are used up
      • The limit to population size that a particular environment can support is called carrying capacity (k)
    • When you’re done writing, put your pens down…
so what do you think is going to happen to the human population
So, what do you think is going to happen to the human population?
  • We will probably reach our carrying capacity.
  • Our growth rate will start to look like most organisms, which is the Logistic Growth Model

Carrying Capacity (k)

What letter does this curve kind of look like?

population limiting factors5
Population Limiting Factors

Population Ecology: Population Growth Models

  • Population growth models
    • Logistic Growth Model
      • Often called the S-shaped growth curve
      • Occurs when a population’s growth slows or stops following exponential growth.
      • Growth stops at the population’s carrying capacity
      • Populations stop increasing when:
        • Birth rate is less than death rate(Birth rate < Death rate)
        • Emigration exceeds Immigration (Emigration > Immigration)
population limiting factors6
Population Limiting Factors

Population Ecology: Population Growth Models

  • Population growth models
    • Logistic Growth Model

The S-curve is not as pretty as the image looks

      • Carrying capacity can be raised or lowered. How?

Example 1: Artificial fertilizers have raised k

Example 2: Decreased habitat can lower k

      • Populations don’t reach k as smoothly as in the logistic graph.
        • Boom-and-Bust Cycles
        • Predator-Prey Cycles
communities

Community Ecology: Communities

Communities
  • Review:
    • A community is a group of interacting populations that occupy the same area at the same time.
communities1

Community Ecology: Communities

Communities
  • Limiting Factors
    • Any abiotic or biotic factor that restricts the numbers, reproduction, or distribution of organisms.
communities2

Community Ecology: Communities

Communities
  • Range of Tolerance
    • The limits within which an organism can exist.
ecological succession

Community Ecology: Ecological Succession

Ecological Succession
  • Ecological Succession
    • The change in an ecosystem that happens when one community replaces another as a result of changing biotic and abiotic factors
ecological succession1

Community Ecology: Ecological Succession

Ecological Succession
  • Ecological Succession
    • Consists of 2 types:
      • Primary Succession
      • Secondary Succession
ecological succession2

Community Ecology: Ecological Succession: Primary Succession

Ecological Succession
  • Ecological Succession: Primary
    • The establishment of a community in an area of exposed rock that does not have topsoil is called Primary Succession.
      • It occurs very slowly at first
ecological succession3

Community Ecology: Ecological Succession: Primary Succession

Ecological Succession
  • Ecological Succession: Primary
    • The first organisms to arrive are usually lichens or mosses, which are called pioneer species.
      • They secrete acids that can break down rock
      • Their dead, decaying organic materials, along with bits of sediment from the rock make up soil.
ecological succession4

Community Ecology: Ecological Succession: Primary Succession

Ecological Succession
  • Ecological Succession: Primary
    • Small weedy plants and other organisms become established.
    • As these organisms die, additional soil is created
ecological succession5

Community Ecology: Ecological Succession: Primary Succession

Ecological Succession
  • Ecological Succession: Primary
    • Seeds brought in by animals, water and wind begin to grow in the soil.
    • Eventually enough soil is present for shrubs and trees to grow.
ecological succession6

Community Ecology: Ecological Succession: Primary Succession

Ecological Succession
  • Ecological Succession: Primary
    • The stable, mature community that eventually develops from bare rock is called a climax community.
ecological succession7

Community Ecology: Ecological Succession: Secondary Succession

Ecological Succession
  • Ecological Succession: Secondary
    • Disturbances (fire, flood, windstorms) can disrupt a community.
    • After a disturbance, new species of plants and animals might occupy the habitat.
ecological succession8

Community Ecology: Ecological Succession: Secondary Succession

Ecological Succession
  • Ecological Succession: Secondary
    • Pioneer species in secondary succession are usually plants that begin to grow in the disturbed area.
    • This is much fasterthan primarysuccession
ecological succession9

Community Ecology: Ecological Succession

Ecological Succession
  • Ecological Succession: End point?
    • Cannot be predicted
    • Different rates of growth &human involvementmake it impossible toknow if a true climaxcommunity has beenreached.
on the left side of your intnb address the following

Biodiversity and Conservation: Introduction

On the left side of your IntNB, address the following:
  • What would happen if all of the jackrabbits in a food web died suddenly?
  • Is the disappearance of one species from Earth important, or will another species fill its niche?
biodiversity

Biodiversity and Conservation: What is biodiversity?

Biodiversity
  • What is Biodiversity?

The variety of life in an area that is determined by the number of different species in that area.

  • There are 2 main types:

Genetic Diversity

Species Diversity

biodiversity1

Biodiversity and Conservation: Why is biodiversity important?

Biodiversity

Penicillin: Derived from bread mold

Teosinte: A distant relative of corn

Domestic corn plant

Madagascar Periwinkle: Used to treat childhood forms of leukemia

extinction rates

Biodiversity and Conservation: Extinctions

Extinction Rates
  • The gradual process of becoming extinct is known as background extinction.
  • Mass extinctions: When a large percentage of all living species become extinct in a relatively short period of time.
  • 250 MYA: Over90% of species died
five most recent mass extinctions

Biodiversity and Conservation: Extinctions

Five Most Recent Mass Extinctions

Cretaceous Period (65 MYA)

Triassic Period (200 MYA)

Permian Period (250 MYA)

Devonian Period (360 MYA)

Ordovician Period (444 MYA)

activity understanding geological time
Activity: Understanding Geological Time
  • Working in your groups, you will get the following supplies:
    • A meter stick
    • A roll of 5 meters of paper
    • Colored pencils
  • Using the worksheet, plot out the dates.
    • 1 million years is a millimeter
    • 1 billion years is a meter