Ch 7   8 ppt 2010 student notes
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Ch 7 8 ppt 2010 student notes

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Ch 7 - 8 student template notes

Ch 7 - 8 student template notes

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  • Purple loosestrife = an introduced species A wetlands plant from Europe - like many species was released accidentally from ballast water in ships docked at port (seeds in water) Also introduced as an herbal remedy No natural enemies here, so spread Has eliminated many native plants that provide food and cover for wildlife in wetlands of Canada and the U.S. Began on the East Coast and has spread Very prolific, spread in water and by livestock that walk through mud that carries the seeds. 20,000 seeds per 1.2 square yards in some areas Tall plant so shades other native plants and blocks their light Livestock doesn’t like is to won’t feed on it. Reduces the carrying capacity of grazing areas Hard to kill. Regrows from roots if plant is cut, burned or sprayed Focus now is on bringing in natural parasites
  • Greater evenness in a community appears more diverfse see pg 119 fig 7.3 In the second picture, is walking through the community would have good chances of seeing all the different species
  • Most numerous groups, with most members know, are the insects and plants Many species have yet to be discovered, many in the tropical rainforests Why so many species? Seems to be related to competition
  • Gray was introduced into GB because it was “cute” It is out-competing the Red Squirrel which is native In winter: Grays eat acorns from oaks. They do well since most of the areas have oak (It is the dominant large tree in GB) Reds may ago extinct in the next 20 years (if not….will be left to areas that do not have any oaks)
  • Hutchinson is the scientist who first suggested this ide See flat worm stucy on page 125. Fig 7.6 Also barnacle example from bio book To save an endangered species we must make sure that all the life requirements for that species are present
  • In 1876 A.R. Wallace suggested idea or realms: Nearctic = North America Neotropial = cental and south america Palaearctic = europe, north asia and north africa Oriental = indian subcontinent and malaysia Australian = aust
  • Other examples = fish and marine mammals, birds and bats and
  • Adaptive radiation: classic example is Darwin’s finches Species diversity and islands 1 and 2) smaller islands have fewer types of habitats also less likely to be found by migrants risk of extinction is higher for smaller pops and smaller islands because they can only support smaller pops (see pg 138) 3) Sources of species on islands = evolution and migration only farther away = fewer migrants Immigration and speciation rate - extinction rate = # of species on island Tends to maintain at a constant rate

Ch 7   8 ppt 2010 student notes Ch 7 8 ppt 2010 student notes Presentation Transcript

  • Chapter 7 - Biological Diversity and Biogeography Case Study Purple Loosestrife
  • What is biological evolution?
    • It’s the change in inherited characteristics of a population from generation to generation.
    • What are some process that lead to biological evolution?
    • 1.
    • 2.
    • 3.
    • 4.
    • 5.
    • Mutations may:
    • Natural Selection
    • Relies on variation of individuals within a species. Genetic diversity is key!
    • Those orgs with traits that make them better fit or adapted survive well, reproduce more and pass these helpful traits on to their offspring.
    • Peppered moth = classic example.
  • Photos by Ken Miller
    • Speciation (evolution of a new species)
    • 1. Geographic isolation of two populations of the same species
    • 2. They each evolve separately
    • 3. Eventually differences accumulate
  •  
  • Reproductive isolation can occur due to mutations too.
    • Migration
    • During migration different selective pressures may be encountered.
    • Populations may become separated
    • Genetic Drift
    • Changes in gene frequency of a population due to chance - not due to being better adapted
    • May greatly impact small populations
    • Dangerous for rare and endangered species
  • Extreme hunting left only 20 Few individuals left – why?
  • Basic Concepts of Biodiversity
    • 3 major concepts:
    • 1. Genetic diversity
    • 2. Habitat diversity:
    • 3. Species diversity:
    • a. Species richness –
    • b. Species evenness –
    • c. Species dominance -
  • Hwk
    • Shannon-Weiner Biodiversity Index
    • Read and do sample problems.
    • Show all work and solve for H ’
    • Also: Calculate Evenness for each problem:
      • Evenness:
      • Formula = H’ / ln S
      • S = number of different species
      • (Absolute evenness = 1)
  • Hwk
    • Pre-lab work for Wed.
    • Answer pre-lab questions.
    • #1 in INB.
    • #2 and 3 become your hypothesis, under purpose on title pg.
    • Calculate S-W biodiversity index for both pictures (fig. 7.4) on page 123.
    • Solve for H ’ and Evenness.
    • Show all work.
    • Species habitat terms:
    • exotic = introduced
    • endemic = native
    • cosmopolitan - very broad distribution but need similar habitat
    • ubiquitous = found almost everywhere even very different habitats
  • How many species on Earth?
    • Uncertain
    • Prior to fogging study: Range =
    • 1 - 3 million
    • After study: 10 -100 million!
  • Interactions Between Species
    • 3 kinds:
    • 1. Competition: negative for both
    • 2. Symbiosis: both benefit
    • It is very common; exists amongst most plants and animals
    • 3. Predation - parasitism: positive for one and negative for the other
    • Exclusion Dominance and Diversity: The Competitive Principle
    • Competitive exclusion = 2 species with exact same requirements cannot coexist in the same habitat. They will compete and the more fit one will win out and persist
  • © 2003 John Wiley and Sons Publishers Fig 7.6 A classical experiment with flour beetles.
    • Niche: how species co-exist.
    • A habitat is where an org lives as compared to what it does to survive, which is its’ ecological niche
    • Species that require the same resources can coexist only if they can utilize them under different env. conditions (different ecological niches).
    • Species that require the same resources can coexist only if they can utilize them under different env. conditions (different ecological niches).
    • Niches can be measured:
    • The range of niche a species will occupy with no competitor is called its’ fundamental niche
    • The range in which it actually lives, if it is having to compete, is called its’ realized niche
  • © 2003 John Wiley and Sons Publishers Fig 7.7 The occurrence of freshwater flatworms in cold mountain streams in Great Britain.
  • Environmental Factors That Influence Diversity!!
    • Diversity varies from place to place
    • Generally, greater in lower latitudes
    • Ecological gradient: the change in relative abundance of a species over an area (ie: change in elevation in the mtns.)
  • © 2003 John Wiley and Sons Publishers Fig 7.10 Change in the relative abundance of a species over an area or a distance is referred to as an ecological gradient.
    • Factors that increase or decrease diversity:
    • Increase diversity :
    • 1. Physically diverse habitat
    • 2. Moderate disturbance
    • 3. Small variation in env. conditions
    • 4. High diversity at one trophic level increases diversity of another level
    • Decrease diversity
    • 1. Environmental stress
    • 2. Extreme environmental conditions
    • 3. Severe limitation of an essential resource
    • 4. Extreme disturbance
    • 5. Recent exotic species
    • 6. Geographic isolation (island effect)
    • Humans greatly affect diversity :
      • Development and industry
      • Favoring one species over another
      • Manipulating environments
    • Species diversity in an area may change over time, seasons, decades, centuries...
  • The Geography of Life
    • The kinds and numbers of species varies greatly from place to place. These large-scale global patterns are called biogeography
    • Biotic Provinces
    • Six “realms” were identified in 1876 based on the types of animals found there:
    • (Remember: classification of orgs are based on evolutionary relationships or similar characteristics)
  • © 2003 John Wiley and Sons Publishers Fig 8.3 The major vegetation realms are also based on genetic factors.
    • Continental drift explains the origin of these provinces as land masses periodically unified (genetic mix and spread of species) and then separated (isolation and speciation)
    • Biomes :
    • Each continent has diverse climates and habitats so diversity of species is high
    • Biome = a kind of ecosystem
    • Similar environmental conditions (selective pressures) lead to evolution of orgs similar in form and function but not genetic heritage or internal make-up.
  • © 2003 John Wiley and Sons Publishers Fig 8.13 Global distribution of the major land biomes.
    • Divergent evolution occurs when a pop. is separated and evolves in isolation from main groups, often under different selective pressures. They have common ancestry and retain some common characteristics of their ancestors. (ex: marine mammals)
  •  
  • © 2003 John Wiley and Sons Publishers Fig 8.10 Evolutionary divergence among honeycreepers in Hawaii.
    • Island Biogeography
      • Generally observe adaptive radiation: species evolve by divergent evolution as they separate into smaller groups, often on different islands, each adapting to a more specialized role (niche)
      • Species diversity and islands:
  • © 2003 John Wiley and Sons Publishers Fig 8.11 Idealized relation of an island’s size, distance from the mainland, and number of species. Pg 138