Midterm Exam 3 Flashcards
(34 cards)
What is Ecology?
The study of interactions among organisms & their environment, which helps scientists describe and explain patterns and make predictions.
Broken into sub-disciplines, increasing in complexity, and beginning with ecology on the organismal level, followed by population, community, ecosystem ecology
Observational vs. Experimental Studies
Observational studies don’t manipulate variables, rather observe and measure occurrences. Experimental studies manipulate variables to induce differences
What is the most important factor to consider for organismal distribution in an environment and why?
Temperature, low or high temperature disrupts biological processes and prevents some species from maintaining homeostasis, limits geographical range of species
Population Ecology
Focuses on groups of interbreeding organisms
Community Ecology
Focuses on the distribution and interactions of and between species in an area to form a functional community (biotic factors only)
Ecosystem Ecology
Focuses on how energy and nutrients cycle through the ecosystem
Rain Shadow
The effect a coastal mountain range has on the precipitation and subsequent vegetation biomass and species abundance (coastal side is often wet, inland dry)
Adiabatic Cooling
Reduction of heat due to air pressure (10C for every vertical 1km)
Sea Breeze
c of water is higher than that of air, therefore water changes T slower, leading to a cool, coastal breeze during the day
Biomes
Biomes are identified on a graph within a region of average temp (X) and annual precipitation (Y), seasonal changes
Line-Transect Sampling
A method of population ecology measurement often used for sedentary organisms (plants)
Ro = sum(lxmx)
Net Reproductive Rate equals the sum of age-specific survivorship (lx) and age-specific fertility (mx, specifically female offspring) to calculate population growth.
> 1: increasing, <1: decreasing, and =1: at equilibrium
Finite Rate of Increase (Lambda)
Ratio of population size from one year to the next (N1/No)
Exponential vs. Logistic Growth
Exponential growth is characterized by a J-Curve, population expands without resource limitations.
Logistic growth is illustrated through an S-Curve, which hovers at about the environment’s carry capacity (K) for the species studied
Semelparity
Organisms produce all their offspring in a single event (ex. salmon, cottonwood)
Iteroparity
Organisms repeatedly reproduce, either seasonally or continuously (ex. birds, mammals)
r vs. K Selected Species
Spectrum!
r selected species focus on exponential growth, poor competition, seen in insects and weeds.
K selected species have stable populations at or near the carrying capacity, seen in large organisms.
Survivorship Curves
Type 1: Minimal decline over time until end of life (ex. chimps)
Type 2: Steady, linear decline in population (ex. lizards)
Type 3: Immediate, rapid decline in population (ex. insects)
Population Dispersal Patterns
Clumped (common), uniform, or random (uncommon, resources are rarely randomly dispersed)
Density Dependent vs. Independent Growth Limitation Factors
Density dependent factors include species interactions (i.e., parasitism, competition)
Density independent factors are natural events (i.e., weather)
Competition
Can be indirect (exploitative) or direct (interference)
Competitive Exclusion Principle
Species with same requirements from the habitat cannot coexist (Gause studies on paramecium)
Resource Partitioning
Allows for differentiation of niches over space and time, enabling species to coexist (ex. warblers in New England, Robert MacArthur)
Character Displacement
aka “Sympatric Speciation”, species occurring in the same geographical area with same fundamental niche leads to divergence in morphology to use resources in different ways
