Population Ecology Chapter 53 Campbell & Reece
Population   group of a single species in the same area Density Dispersion Video of GYE bears
Density <ul><li>Dynamic (immigration, emigration, birth death) </li></ul><ul><li>Mark-recapture method </li></ul><ul><li>I...
Patterns of Dispersion <ul><li>Clustered </li></ul><ul><ul><li>Environmental factors unevenly distributed </li></ul></ul><...
<ul><li>Image from Wikipedia,   http://en.wikipedia.org/wiki/File:Population_distribution.svg </li></ul>
 
 
Survivorship Curves http://www.bio.miami.edu/dana/pix/survivorship.gif
Tioga Pass, California (3,031m) home of the Belding’s ground  squirrel <ul><li>_3,031 m </li></ul>
 
Reproductive Output <ul><li>“ Big-bang” reproduction – “semelparity” </li></ul><ul><ul><li>Reproduce 1x in life then die <...
Repeat reproduction (iteroparity) – <ul><ul><li>* common in more dependable, predictable environments </li></ul></ul><ul><...
Trade-offs <ul><li>Ideal = many offspring, well-cared for, repeatedly over lifespan </li></ul><ul><li>This does not exist ...
Growth Curves <ul><li>Exponential growth  (geometric) </li></ul><ul><ul><li>Ideal, limitless growth </li></ul></ul><ul><ul...
Limiting Factors    Carrying Capacity <ul><li>FWARPS </li></ul><ul><li>Carrying Capacity (K) = max # of individuals of a ...
Kaibab Plateau , Arizona http://depts.alverno.edu/nsmt/youngcc/research/kaibab/story3.html
Rule of 70 <ul><li>70 / growth rate  = doubling time! </li></ul><ul><li>Learn this, avoid massive debt </li></ul>
K-selection <ul><li>Sensitive to population density </li></ul><ul><li>More successful in crowded environments </li></ul><u...
R-selection <ul><li>Maximize reproductive success in uncrowded environments </li></ul><ul><li>Density-independent </li></u...
Reproductive Strategies <ul><li>r- Selected (maximum growth rate, below carrying capacity) </li></ul><ul><ul><li>Early rep...
Limits on Population Growth <ul><li>Density Dependent Limits </li></ul><ul><ul><li>Food </li></ul></ul><ul><ul><li>Water <...
Limiting Factors <ul><li>Density Independent </li></ul><ul><ul><li>Fires, floods, drought, etc </li></ul></ul><ul><ul><li>...
Population Dynamics <ul><li>Isle Royale Moose and Wolves </li></ul>
Human Population <ul><li>Look at 53.22…seriously look at it </li></ul>
http://economicedge.blogspot.com/2009_05_17_archive.html
 
 
Demographic Transition <ul><li>HIGH birth rate, HIGH Death Rate </li></ul><ul><li>HIGH Birth Rate, Low Death Rate </li></u...
Age Structure Pyramids http://www.census.gov/ipc/www/idb/country.php
 
 
Ecological Footprint <ul><li>footprint  as homework </li></ul>
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Population ecology ch 53

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Chapter 53 in Cambpell & Reece Biology, 8th edition.

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  • Sign surveys are “non-invasive” Collected 33,000 hair samples ($5 million project) across 3.2 M Ha 200 paid employees and hundreds more volunteers 563 different grizzly bear DNA samples
  • LINEAR SCALE
  • SEMI-LOG SCALE
  • Plot of the proportion of the cohort still alive at each age Type I – flat at start (high survivorship), steep drops late in life. Often few offspring per parent, high care. Many large mammals (incl humans) Type III – huge drops at start, low mortality afterwards. Often hundreds/millions of offspring per parent, no parental care. Long-lived plants, many fishes, most marine invertebrates. Type II are intermediate – constant death, often from predation (Belding’s Ground Squirrel)
  • Salmon “ annual” plants complete life in one season, usually semelparous
  • Animals can change behavior Tasmanian devils – traditionally &lt; 12 % bred in 1 st year of life. now, a contagious face cancer has devastated population, leading to a change in lifestyles / reproductive strategies In 2004, in one area, 13% bred in year 1; in 2006, it was 83%! To our knowledge, this is the first known case of infectious disease leading to increased early reproduction in a mammal,&amp;quot; the researchers write. They believe the reproductive changes can be explained, at least partially, by less competition for food, resulting in a faster growth rate for young devils and a quicker route to sexual maturity.
  • Bears won’t usually bother with salmon after they’ve spawned, as they have used so much fat/nutrients in spawning Example in book (p1180) of modifying brood size in European kestrels…increased brood, decreased parental survival. Decrease brood, increased survival.
  • In 36 hours, under ideal conditions, one bacterium could reproduce to cover the globe shin deep! (of course these ideal conditions are impossible) Even a pair of slow-growing elephants (to use Darwin’s example, 6 per 100 years) could have 19 million offspring in 750 years! J-curves common when a population is in a new environment, or there has been a major disturbance S. Africa elephants in Kruger National Park – even that had exponential growth, for 60 years after the cessation of hunting Which are J-curves? 1. A seed that lands on an island with no other plants. 2. A population of Kirtland warblers that compete for nesting space in Michigan jack pine forests. 3. A population of barnacles that compete for space on a rock in the intertidal zone. 4. A population of rabbits in the first few years after their main predator is pushed to extinction . A bacterium placed in a fresh Petri dish full of growth medium. A population of red grouse that carry a contagious parasitic nematode. A population of hares in Canada; the hares are eaten by lynx. An invasive mussel that colonizes a freshwater lake.
  • 1. Food, Water, Air, Reproduction, Protection, Space (Energy, Shelter, refuge from predators, nutrient availability, water, nesting sites) 2. K varies in space and time, and also with behavioral choices of organisms 3. Under logistic growth, per capita rate of increase (r) decreases as you approach carrying capacity (but actual # still going up) 4. Max # of new individuals per year is found at about ½ K , with a large population and not-too-small growth rate. 5. Reality – not often a smooth adjustment to environmental factors: lag time , boom and bust
  • http://www.biologycorner.com/worksheets/kaibab.html “ classic example” of predator control 1906 TR Roosevelt created Grand Canyon Game Reserve to protect 4,000 mule deer Also, reduction of grazing and wildfire control after national park status increase available browse
  • Reproductive Strategies In an uncrowded environment, such as a recently abandoned crop field, natural selection pressure tends to favor populations that invest heavily in offspring, have shorter life spans, capacity for widespread dispersion, and usually provide little or no parental care for offspring (for example, mosquitoes, ragweed, or mice). These populations tend to increase exponentially and often are referred to as r-strategist, where r refers to the intrinsic rate of growth of the population. In contrast, crowed conditions favor organisms with lower rates of population growth, but improved capabilities to utilize and compete for resources. These populations maintain themselves at levels close to carrying capacity (K) and are referred to as K-strategist. Biologist refer to the types of selection pressure placed on populations as r-selection, if individuals that reproduce rapidly and abundantly are favored, and as K-selection, if individuals that compete well in crowded conditions are favored over time. References Campbell, N. E. &amp; Reece, J. B. (2002). Biology (6 th ed.). San Francisco: Benjamin Cummings. Odum, E. (1997). Ecology: A Bridge Between Science and Society . Sunderland, MA: Sinauer Associates, Inc. Raven, P. H. &amp; Johnson, G. B. (2002). Biology (6 th ed.). McGraw-Hill.
  • Limits on Population Growth Carrying capacity (K) is the maximum number of organisms of a population that can be supported by a particular habitat. As population numbers approach the carrying capacity of an environment, in other words as density increases, competition for resources is amplified. Density-dependent factors in an environment include available food, nutrients in the soil, water, and shelter, among many others. The buildup of metabolic wastes also increases with density and adversely affects many populations as well. Weather, climate, and human activities can be density-independent factors which affect the environment. In the case of catastrophic events or the pressure of toxins, populations are affected regardless of size. Populations recover at different rates, some even experiencing a permanent decline after a major change in the environment. References Campbell, N. E. &amp; Reece, J. B. (2002). Biology (6 th ed.). San Francisco: Benjamin Cummings. Raven, P. H. &amp; Johnson, G. B. (2002). Biology (6 th ed.). McGraw-Hill. Image Reference NOVA Development Corp. (1995) Birds #2516 . Art Explosion, Volume 2 Clip Art NOVA Development Corp. (1995) Wilderness #319 . Art Explosion, Volume 2 Clip Art
  • Mice are stressed by high population densities, yield to hormonal changes that delay sexual maturation, shrink reproductive organs, depress the immune system…increase in mortality, decrease in birth rates
  • Isle Royal Moose-Wolf educational video: http://www.isleroyalewolf.org/educ_matls/educ_matl/video.html Lynx populations – controlled by hare populations – controlled by winter food availability – partially controlled by sunspot activity (less ozone  more UV  more sunscreen chemicals and fewer anti-browse chemicals!) !!!
  • Pre-history of world population (from US Census) http://www.census.gov/ipc/www/worldhis.html http://www.un.org/esa/population/publications/sixbillion/sixbilpart1.pdf
  • The world population growth rate rose from about 1.5 percent per year from 1950-51 to a peak of over 2 percent in the early 1960s due to reductions in mortality. Growth rates thereafter started to decline due to rising age at marriage as well as increasing availability and use of effective contraceptive methods. Note that changes in population growth have not always been steady. A dip in the growth rate from1959-1960, for instance, was due to the Great Leap Forward in China. During that time, both natural disasters and decreased agricultural output in the wake of massive social reorganization caused China&apos;s death rate to rise sharply and its fertility rate to fall by almost half. (From U.S. Census Bureau)
  • 150 years for Sweden, probably the same for Mexico Increase in sanitation, medicine, education, women’s status Reproductive rates reflect cultural norms…slower to change Factors that Affect Birth/Fertility Rates Importance of children to labor force Urbanization (better access to family planning, less need for labor) Cost of raising/educating children Educational/Employment opportunities for women – in developing countries, women with no education have 2 more kids than women with high school education Infant mortality rate …if they will live, less incentive to have more Age of marriage/first child – Pension systems – reduces need to have children as old-age support system *Government rewards/penalties for children (U.S. has tax credits, China has penalties) Availability of legal abortions Availability of reliable birth control Culture, religion, tradition, etc. (Catholics, Mormons, etc.) Affects on Death Rates availability and affordability of health care food supply and nutrition Sanitation Water system Hygiene
  • Population ecology ch 53

    1. 1. Population Ecology Chapter 53 Campbell & Reece
    2. 2. Population group of a single species in the same area Density Dispersion Video of GYE bears
    3. 3. Density <ul><li>Dynamic (immigration, emigration, birth death) </li></ul><ul><li>Mark-recapture method </li></ul><ul><li>Index of population size (scat, burrows,etc “sign surveys”) </li></ul><ul><ul><li>Glacier NP DNA study podcast or MSNBC </li></ul></ul>
    4. 4. Patterns of Dispersion <ul><li>Clustered </li></ul><ul><ul><li>Environmental factors unevenly distributed </li></ul></ul><ul><ul><li>Mating </li></ul></ul><ul><ul><li>Defense/predation </li></ul></ul><ul><li>Uniform </li></ul><ul><ul><li>Territoriality </li></ul></ul><ul><ul><li>Absence of strong attraction/repulsion </li></ul></ul><ul><ul><li>Key environmental factors evenly distributed </li></ul></ul><ul><li>Random – not that common </li></ul>
    5. 5. <ul><li>Image from Wikipedia, http://en.wikipedia.org/wiki/File:Population_distribution.svg </li></ul>
    6. 8. Survivorship Curves http://www.bio.miami.edu/dana/pix/survivorship.gif
    7. 9. Tioga Pass, California (3,031m) home of the Belding’s ground squirrel <ul><li>_3,031 m </li></ul>
    8. 11. Reproductive Output <ul><li>“ Big-bang” reproduction – “semelparity” </li></ul><ul><ul><li>Reproduce 1x in life then die </li></ul></ul><ul><ul><li>Favored with poor survival of either parent or offspring </li></ul></ul><ul><ul><li>Often occur with highly variable, unpredictable environments </li></ul></ul>Image from scienceblogs.com
    9. 12. Repeat reproduction (iteroparity) – <ul><ul><li>* common in more dependable, predictable environments </li></ul></ul><ul><ul><li>High parental care, low numbers of offspring, high survival </li></ul></ul>Tasmanian Devil, from http://news.mongabay.com/2008/0714-hance_devils.html
    10. 13. Trade-offs <ul><li>Ideal = many offspring, well-cared for, repeatedly over lifespan </li></ul><ul><li>This does not exist </li></ul><ul><li>Reproduction is costly (increased maternal mortality) </li></ul>
    11. 14. Growth Curves <ul><li>Exponential growth (geometric) </li></ul><ul><ul><li>Ideal, limitless growth </li></ul></ul><ul><ul><li>Must be temporary </li></ul></ul><ul><ul><li>J-shaped curve </li></ul></ul><ul><ul><li>Exponential Growth Simulator http://nortonbooks.com/college/biology/animations/ch34a01.htm </li></ul></ul><ul><ul><li>Logistic Growth </li></ul></ul><ul><ul><li>Carrying capacity – There are limits to growth! </li></ul></ul><ul><ul><li>S-curve (sigmoid) </li></ul></ul><ul><ul><li>Logistic Growth Simulator : http://nortonbooks.com/college/biology/animations/ch34a02.htm </li></ul></ul>
    12. 15. Limiting Factors  Carrying Capacity <ul><li>FWARPS </li></ul><ul><li>Carrying Capacity (K) = max # of individuals of a species that can occupy a certain habitat </li></ul><ul><li>Lag time, Boom & bust (rough transition) </li></ul>
    13. 16. Kaibab Plateau , Arizona http://depts.alverno.edu/nsmt/youngcc/research/kaibab/story3.html
    14. 17. Rule of 70 <ul><li>70 / growth rate = doubling time! </li></ul><ul><li>Learn this, avoid massive debt </li></ul>
    15. 18. K-selection <ul><li>Sensitive to population density </li></ul><ul><li>More successful in crowded environments </li></ul><ul><li>Often iteroparous </li></ul>http://z.about.com/d/healing/1/0/7/N/gtotem_koala.jpg
    16. 19. R-selection <ul><li>Maximize reproductive success in uncrowded environments </li></ul><ul><li>Density-independent </li></ul><ul><li>Often semelparous </li></ul><ul><li>Disturbed habitats </li></ul>http://www.hot-screensaver.com/wp-myimages/cockroach.jpg
    17. 20. Reproductive Strategies <ul><li>r- Selected (maximum growth rate, below carrying capacity) </li></ul><ul><ul><li>Early reproduction </li></ul></ul><ul><ul><li>Short life span </li></ul></ul><ul><ul><li>High mortality rate </li></ul></ul><ul><ul><li>Little or no parental care </li></ul></ul><ul><ul><li>Large investment in producing large numbers of offspring </li></ul></ul><ul><ul><li>Below carrying capacity </li></ul></ul><ul><ul><li>Examples: </li></ul></ul><ul><ul><ul><li>Bony fish </li></ul></ul></ul><ul><ul><ul><li>Grasshoppers </li></ul></ul></ul><ul><li>K-Selected (maximizes population size near carrying capacity) </li></ul><ul><ul><li>Late reproduction </li></ul></ul><ul><ul><li>Long life span </li></ul></ul><ul><ul><li>Low mortality rate </li></ul></ul><ul><ul><li>Extensive parental care </li></ul></ul><ul><ul><li>Greater investment in maintenance and survival of adults </li></ul></ul><ul><ul><li>At or near carrying capacity </li></ul></ul><ul><ul><li>Examples: </li></ul></ul><ul><ul><ul><li>Sharks </li></ul></ul></ul><ul><ul><ul><li>Elephants </li></ul></ul></ul>Slide adapted from BioEd Online BioEd Online
    18. 21. Limits on Population Growth <ul><li>Density Dependent Limits </li></ul><ul><ul><li>Food </li></ul></ul><ul><ul><li>Water </li></ul></ul><ul><ul><li>Shelter </li></ul></ul><ul><ul><li>Disease </li></ul></ul><ul><li>Density Independent Limits </li></ul><ul><ul><li>Weather </li></ul></ul><ul><ul><li>Climate </li></ul></ul>Water and shelter are critical limiting factors in the desert. Fire is an example of a Density independent Limiting factor. Slide adapted from BioEd Online BioEd Online
    19. 22. Limiting Factors <ul><li>Density Independent </li></ul><ul><ul><li>Fires, floods, drought, etc </li></ul></ul><ul><ul><li>Can be exacerbated by density </li></ul></ul><ul><ul><li>Density Dependent </li></ul></ul><ul><ul><li>Disease, territoriality, competition, predation, toxic waste, intrinsic factors (physiological) </li></ul></ul>
    20. 23. Population Dynamics <ul><li>Isle Royale Moose and Wolves </li></ul>
    21. 24. Human Population <ul><li>Look at 53.22…seriously look at it </li></ul>
    22. 25. http://economicedge.blogspot.com/2009_05_17_archive.html
    23. 28. Demographic Transition <ul><li>HIGH birth rate, HIGH Death Rate </li></ul><ul><li>HIGH Birth Rate, Low Death Rate </li></ul><ul><li>Low Birth Rate, Low Death Rate </li></ul>
    24. 29. Age Structure Pyramids http://www.census.gov/ipc/www/idb/country.php
    25. 32. Ecological Footprint <ul><li>footprint as homework </li></ul>

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