74 terms

Environmental Science Test 3

Caddo Parish Magnet High School 2013- 2014 Ms. Blackwell
Charles Lyell
- suggested the world was much older than previously thought and capable of undergoing gradual, but profound change over time
Thomas Malthus
- wrote "Essay on the Principle of Population" (1798)
natural selection
- organisms produce more offspring than can actually survive
- individuals with superior attributes are more likely to live and reproduce than those less well- endowed
- b/c more fit individuals are more successful in passing along favorable traits to offspring, the whole population will gradually change to be better suited for its particular environment
- gradual change in species
On the Origin of Species
- Darwin's published (1859)work explaining his theory of evolution through natural selection
- the acquisition of traits that allow a species to survive in its environment
1. acclimation - individual organism responds immediately to changing environment
2. natural selection- takes place over numerous generations and involves many individuals
selection pressures
- during the course of a species lifetime (1 million or more years) some mutations are thought to have given individuals with mutations an advantage under these
- the result is a species population that differs from those of numerous preceding generations
Justus von Liebig
- chemist who, in 1840, proposed that the single factor in shortest supply relative to demand is the critical factor determining where a species lives
critical factor
- single factor in shortest supply relative to demand that determines where a species lives
- defined by Justus von Liebig
Victor Shelford
- ecologist who expanded Liebig's principle
- stated each environmental factor has both minimum and maximum levels (tolerance limits) beyond which a particular species cannot survive or is unable to reproduce
- the single factor most essential for survival is the critical factor that limits where an organism can live
tolerance limits
- defined by Victor Shelford
- minimum and maximum levels beyond which a particular species cannot survive or is unable to reproduce
- requirements and tolerances of species are examples
the place or set of environmental conditions in which a particular organism lives
ecological niche
describes either the role played by a species in a biological community or the total set of environmental factors that determine a species distribution
Charles Elton (1900-1991)
- British ecologist
- first defined the concept of niche (1927)
- said niche defined by way an organism obtains food, the relationship it has with other species, and the services it provides to its commnity
G. E. Hutchinson (1903- 1991)
- American limnologist
- proposed more biophysical definition of niche
- niche is more complex than idea of a critical factor
- a graph of a species' niche would be multidimensional with many factors displayed simultaneously...like an electron cloud
- has a broad ecological niche- a wide range of tolerance for many environmental factors
- has more exacting habitat requirements
- tends to have lower reproductive rates and care for young longer
- adjective describing something found in one location and not anywhere else
G. F. Gause (1910- 1986)
- Russian microbiologist that proposed the idea that, " complete competitors cannot coexist" to explain why mathematical models of species competition always ended with one species disappearing
- one species must die out, change behavior or physiology, or find a new habitat
competitive exclusion principle
- stated that not 2 species can occupy the same ecological niche for long
- the 1 that is more efficient in using available resources will exclude the other
resource partitioning
- process of niche evolution
- can allow several species to utilize different parts of the same resource and coexist within the same environment
- the development of a new species
- Darwin believed species arise only very gradually
Stephen Jay Gould
- evolutionary scientist
- suggested many species may be relatively stable for long times and then undergo rapid speciation (punctuated equilibrium) in response to environmental change
geographic isolation
- mechanism of speciation
- allopatric speciation
- species arise in non- overlapping geographic locations (Galapagos finches)
behavioral isolation
- divides sub-populations
- ex. virtually identical tree frog species have different mating calls
sympatric speciation
- speciation that takes place in the same location as the ancestor species
- ex. almost identical tree frogs- one species has twice the number of chromosomes as the other
- ferns are prone to this
directional selection
shift in characteristics toward one extreme
stabilizing selection
narrowing of the range of a trait
disruptive selection
divergence of traits to both extremes
- position Darwin held on "The Beagle"
- currently the drug of last resort for epidemics caused by antibiotic- resistant infections
H1N1 flu
- flu family notorious as source of the worst flu epidemic in recorded history - 1918 Spanish flu that killed > 50 million
- this flu family also infects pigs, but rarely kills them
- pig viruses have begin to evolve faster than human forms
- the study of types of organisms and their relationships
- allows us to trace how organisms have descended from common ancestor
- relationships displayed in family tree
-composed b the most specific levels of the tree, genus, and species
- scientific or Latin names that identify and describe species using Latin or Latinized nouns and adjectives, or names of people and places
6 kingdoms
1. animals
2. plants
3. fungi (molds and mushrooms)
4. protists (algae, protozoans, slime molds)
5. bacteria (or eubacteria)
6. archaebacteria (ancient single celled organisms; extremophiles)
- antagonistic relationship within a biological community
- shapes a species population and biological community by causing individuals and species to shift their focus from one segment of a resource type to another
intraspecific competition
- competition among members of the same species
- ex. warblers specialize on different areas of the forest's trees
1. young of the year disperse
2. strong territoriality exhibited
3. resource partitioning between generations
interspecific competition
- competition between members of different species
- any organism that feeds directly on another living organism (whether or not it kills the prey)
- herbivores, carnivores, omnivores...parasites and even pathogens
- scavengers, detritivores, and decomposers - feed on dead organism and are not predators
- affects...
1. all stages in the life cycles of predator and prey species
2. many specialized food- obtaining mechanisms
3. the evolutionary adjustments in behavior and body characteristics that help prey escape being eaten and predators more efficiently catch their prey
predator- mediated competition
- a superior competitor in a habitat builds up a large pop. than its competing species
- predators take note and increase their hunting pressure on the superior species, reducing its abundance and allowing the weaker competitor to increase its numbers
- the response of predator to prey or vice verse, over tens of thousands of years, produces physical and behavioral changes in this process
- can be mutually beneficial
Batesian mimicry
- certain species that are harmless resemble poisonous or distasteful ones, gaining protection against predators who remember a bad experience with the actual toxic organism
- named after English naturalist H. W. Bates (a traveling companion of Alfred Wallace)
Mullerian mimicry
- 2 unpalatable or dangerous species look alike- when predators learn to avoid either species, both benefit
- named after biologist Fritz Muller
- 2 or more species live intimately together with their fates interlinked
- often enhance the survival of one or both partners
- often entail some degree of coevolution
- symbiosis in which both species benefit
- ex. in lichens, a fungus and a photosynthetic partner combine tissues to mutual benefit
- survival of the fittest many also mean survival of organisms that can live together
E. O. Wilson
- Harvard entomologist who, in 2005, explained a 500 year old agricultural mystery in Hispaniola
- reasoned that mutualism developed between tropical fire ants native to the Americas and a sap- sucking insect that was probably intro. from the Canary Islands in 1516 on plantain shipment
- sap- suckers were dist. over whole island, and 1518- great crop die off
- ants consumed the foreign insects' excretions of sugar and protein, this protected them from predators, and insect pop. exploded
- it had been assumes fire ants caused crop die off (until 2005)
- type of symbiosis in which one member clearly benefits and the other is neither benefitted or harmed
- ex. mosses and trees
- form of predation- may also be considered symbiosis- one species (parasite) depends entirely on another and harms it (host)
keystone species
- species that plays a critical role in a biological community that is out of proportion to its abundance
- species that exerts influence by changing competitive relationships
- effect of this kind of species on communities often ripples across tropic levels
- even microorganisms can be this
- more common in aquatic habitats than terrestrial ones
- "keystone set" of organisms
primary productivity
- rate of biomass production - an indication of the rate of solar energy conversion to chemical energy
net primary production
- energy left after respiration
- an expression of the total number of organism in a biological community
- often inversely related to the total diversity of the community- communities w/ a large # of species often have only a few members of any given species in a particular area
- measure of the number of different species, ecological niches, or genetic variation present
general rule of abundance and diversity
- diversity decreases by abundance within species increases as we go from the equator to the poles
ecological structure
- refers to patterns of spatial distribution of individuals and populations within a community as well as the relation of a particular community to its surroundings
- the number of species at each tropic level and the number of tropic levels in a community
- used to group herbivores based on the specialized ways they feed
- fruit eaters, leaf nibblers, root borers, seed gnawers, sap suckers
3 kings of stability or resiliency in ecosystems
1. constancy - lack of fluctuations in composition or functions
2. inertia - resistance to perturbations
3. renewal- ability to repair damage after disturbance
Robert MacArthur
- grad student at Yale who, in 1955, proposed that the more complex and interconnected a community is, the more stable and resilient it will be in the face of disturbance
edge effects
- relationships that form as a result of the boundary between 1 habitat and its neighbors
- the boundaries between adjacent communities
closed community
a community that is sharply divided from its neighbors
open community
a community with gradual or indistinct boundaries over which many species cross
J.E.B. Warming (Norway) & Chandler Cowles (US(
- came up w/ idea that communities develop in a sequence of stages, starting wither from bare rock or after a severe disturbance
climax community
- community that developed last and lasted the longest
- F.E. Clements
F.E. Clements
- came up w/ idea of the climax community
- biogeographer
- viewed the process as a relay- species replace each other in predictable groups and in a fixed, regular order
- every landscape has a characteristic climax community, determined mainly by climate
- to him climax comm. was the maximum complexity and stability possible
H.A. Gleason
- contemporary of Clements
- saw community hixtory as an unpredictable process
- came up w/ organismal theory-a climax community is like the maturation of an organism; both communities and organisms begin simply and primitively, maturing until a complex community is developed
- argued species are individualistic
- we think ecosystems are uniform and stable b/c out lifetimes are too short and our geographic scope limited to understand dynamic nature
primary succession
- land that is bare is colonized by living organisms where none lived before (sandbar, mudslide, rock face, volcanic flow)
- organisms change the environment
secondary succession
- when an existing community is disturbed and a new one develops from the biological legacy of the old
- organisms change the environment
pioneer species
- microbes, mosses, lichens that can withstand a harsh environment w/ few resources
- when they die, their bodies create patches of organic matter
- 1st colonists
- any force that disrupts the established patterns of a species diversity and abundance, community structure, or community properties
- animals, people, landslides, mudslides, hailstorms, earthquakes, tidal waves, tornadoes, wildfires, volcanos
- sets back supreme competitors and allows less- competitive species to persist
disturbance- adapted species
- species that survive fires underground, or resist the flames, and then reseed quickly after fires