Ecology exam 1
Terms in this set (54)
Study of the interactions that determine the distribution and abundance of organisms
Where organisms are found
How many in a given area
Ecology three points of view
1.) Descriptive- Describes natural history and vegetation. Foundation of all ecological science, historically important. Some areas and organisms still poorly known.
2.) Functional- dynamics and relationships, populations, and communities. Includes proximate causes: responses to immediate factors of the environment.
3.) Evolutionary- Clamminess ultimate causes. Why natural selection has favored a particular ecological solutions.
Ecology three approaches
1.) theoretical creative thinking and modeling to arrive at interesting ideas. Yet so much complexity results rarely match models exactly. Use probes (violated assumptions) to investigate further ideas, power in application.
2.) Laboratory- take those ideas to controlled conditions of the lab. Controls as many variables as possible to iron out the details.
3.) Field- Investigate in natural habitats where complexities are operating. All to further knowledge in the distribution and abundance
change in allele frequencies through time in a population. Leads to adaption. Evolutionary change by natural selection
Increase or decrease in the number of individuals with certain genotypes as a result of differential survival and reproduction.
Phenotypes of one extreme are selected against
Phenotypes near the mean are selected for
Phenotypes at the extremes are favorable over the mean.
Tend to lay a given number of eggs even after removal
Tend to keep laying until the nest is full
Coevolutionary arms race
Anything you do I can can do better. Predator-Prey interactions and Host-Parasite interactions. Selection will favor improvements on one side, than the other
Four units of selection
Share the qualities necessary to affect evolution.
1.) Individual selection- Most common (stronger)
2.) Gametic selection- Factors with sperm and eggs. (Very rare and weak)
3.) Kin selection- through relatives
4.) Group selection- variable groups (extremely rare, if at all)
Survival value of behavior. Way behavior contributes to survival and reproduction depends on ecology
Migration is hard on birds, pressure to do well
Three strategies of optimal migration
1.) Time minimization- early arrives increase fitness, countered by high energy costs. High adult nest predation risks.
2.) Energy minimization- Favored when use of energy is high. Especially if food resources are uncommon along the way
3.) Cost of transportation- another energy minimization strategy focused on entire annual energy cycle
Fuel deposition rate
fraction of body mass accumulated per day
fat and protein, fraction of body mass
Increase paternity in light of new arrivals. (lion example)
Why are organisms found in some place and not others? Pattern and process
Liebigs law of the minimum
Limited by factor in least amount of relative to requirements, single nutrient for crops. Revolutionized fertilizers, yet later criticized
More complex as nutrients combine affects.
Provides useful starting point
Treat factors separate initially, then combine
Shelfords law of tolerance
Controlled by that factor for which organism has the narrowest range of tolerance. Attempt to determine a range of single factor over which a species can survive
Biotic factors that limit distribution
1.) Dispersal- (or lack there of) they may not have the ability to get there
2.) Predators- Being eaten by another organism may affect their local distribution
3.) Disease- being pathogenic toward another organism may also affect their local distribution
4.) Competition- one species may out compete another and affect their distribution
Three modes of dispersal
1.) Diffusion- gradual movement of a population. Typically through difficult areas over many generations
2.) Jump dispersal- movement of individuals organisms across a large distances. Typically forms a population over a short time
3.) Secular dispersal- diffusion dispersal where natural selection causes groups to evolutionary diverge over time. Typically a bio-geographic process not well studied.
Discrepancy between how fast species are able to disperse versus what calculation show they should disperse.
Abiotic factors that limit distribution
2.) Moisture- ability to maintain water use and their distribution.
Plant adaptations to avoid desecration to arid conditions
1.) Improve water up take at roots.
2.) Reduce water loss. Close stomata, Prevent cuticle respiration, Reduce leave surface area.
3.) Store water efficiently.
Experiment can tease out genetic affinities as evidence for adaption to varying conditions
Geographic range size for mammals decreased as one moved from polar to equatorial regions
Three ecological explanations for Rapoports Rule
1.) Climate variability is greater at high latitudes. Perhaps only organisms with a broad tolerance in climate can live there and thus occupy larger ranges
2.) Product of glaciation, following retreat, only a few species could repopulate northern regions.
3.) Less competition near the poles, lower diversity, fewer species. Able to spread out more and thus, exhibit larger ranges.
Distribution and abundance show a positive relationship.
Three ecological explanations for Hanski's rule
1.) Sampling model- Argues that the observation is simply and artifact of sampling
2.) Ecological specialization model- Generalists will become wide spread and abundant, while specialists will only be able to exploit limited areas
3.) Local population model- good dispersers are wide spread and abundant, bad dispersers are not wide spread and abundant
A group of organisms of the same species occupying a particular space at a particular time
Genetic population, maybe a breeding subdivison of a population. Share common gene pool
Number of individuals per unit area or volume
Four population parameters that change density
1.) Natality- births.
2.) Mortality- Deaths
3.) Immigration- movements in
4.) Emigration- Movements out
each individual is easily recognized as a separate genetic individual
zygote or spore forms a module that produces similar modules, common in plants and some inverts
Two levels of population structure of modular organisms
1.) Ramets- modular unit. Ex. blade of grass, aspen tree trunk
2.) Gamets- genetic individuals, composed of one or more modular units. Ex. tuft of grass or grove of aspen trees
Number per unit area or volume
Count all of the individuals in a given area and divide by the area or volume
Collect data on a sample in order to estimate the total population density
Assumptions of capture-recapture
1.) All equal probability of being caught.
2.) No incoming individuals between recapture
3.) Marked and unmarked die and or leave at same rate.
4.) No marks are lost
represents some relatively constant but unknown relationship to the total population size
Production of new individuals by birth, hatching, germination, or fission
Organisms physiological potential reproductive capacity, is usually inversely related to to amount of parental care
One female salamander may lay several hundred eggs per year
Ecological potential, number of viable young produced during a time period
Sane female salamander may sire 30 young during a two year period
Deaths, why organisms die and how others avoid it
Age of deaths of individuals within a population
Maximum life span set by physiology
Following disease, predation, or another natural hazard