Exam 1 Flashcards
What is ecology?
study of the interactions between organisms and their environment
What kind of interactions does ecology look at?
Energy loss/gain, population dynamics, etc.
How do ecologists answer their questions? (2)
Mathematical models and manipulative experiments
Explain the difference in warmth between the equator and the poles of the earth
At the poles sunlight hits the earth at an angle and thus the rays are spread over a larger area, making the energy less concentrated while at the equator the rays hit the earth near to perpendicular, so there is more solar energy per unit area.
How do the angles the sun hit the earth (equator vs. poles) influence air currents?
Since the equator is warmer, this causes air to lift towards the atmosphere, creating a low pressure area (Hadley cell), while in the poles the cold air pulls air downwards creating a higher pressure (polar cell). The movement of air between these two cells is driven by the the movement of the cells and by the exchange of energy at the polar front
How do the cells described earlier in combination with the earths spin create the patterns of air movement at the earths surface?
the air at the equator will flow in the opposite direction of the earths spin and the combination of air currents moving away from high pressure or towards low pressure areas creates weterlies and easterlies as shown in figure 2.9 (pg 28)
Climate
Long term description of weather at a given location
caused by earth’s tilt (latitudinal climate patterns) and proximity to oceans
potential evapotranspiration (PET)
max amount of water expected to be lost from the landscape by evaporation and/or transpiration under climatic conditions (assuming NO water limitation)
Primary driver = temperature
actual evapotranspiration (AET)
water actually lost from a landscape by evaporation and transpiration
Primary drivers = temperature and percipitation
What type of biomes have the most PET?
Those that are hot
What type of biome will have the most AET?
Those that are hot and wet (have more water to lose) ie.// tropical rainforest has a higher AET than a desert since there is less water available to lose in a desert
What if the earth did not have a tilt?
No seasons, there would be less land at a liveable temperature
What if the earth had a more dramatic tilt?
Seasons would be more extreme and it would be harder to survive year round in a given area
what determines ocean currents?
surface winds
Local factors that influence climate (5)
Rain shadow, continent size, elevation, vegetation, topography (slope direction)
Tropical rainforests
High growth rates multiple layers (diversity)
Precipitation outweighs water loss due to temperature all of the year
Polar regions
scattered cover, low temperatures, high winds, dry, low growth rates
Tropical seasonal forests/savannas
Some of the year low precip, some high. Wet and dry seasons. Somewhat lower diversity and growth rate. Frequency of fires in dry season influences plant life. more shrubs etc than trees
Deserts
Sparse populations, high temp, low water availability, usually around 30* latitude N and S (high pressure areas)
Temperate grasslands
seasonal variability (warm wet, cold dry), frequent fires, grass dominant
Temperate shrub and woodlands
seasonality of precipitation, somewhat diverse, some fires
aquatic biomes
Fresh or saltwater-> influences strategy to minimize water loss/gain
Deep vs shallow water (temperature more influenced by air temp in shallow water), available light changes as well
Moving vs. still water
Tidal zones: variation in wet vs. dry and temperature
Lotic
moving freshwater
lentic
still freshwater
Estuarine
at river junctions, salinity varies due to proximity of ocean and tidal behavior
Salt marshes
Often next to estuaries, salinity gradients based on plant tolerance to salinity, flood often
Mangroves
shallow estuaries inhabited by salt tolerant trees and shrubs
coral reefs
warm shallow ocean waters, slow growth but very diverse, production rate highest on earth
rocky intertidals
influenced by tides (species need to be able to deal with temperature change and change from wet to dry environments)
Acclimation
individual’s response to a factor
Adaptation
evolutionary response across generations
Acclimatization
individual’s response to many factors
endotherm
animal capable of internal generation of heat
ectotherm
animal dependent of external sources for heat
homeothermy
organism maintains body temp at constant level
poikilothermy
organism’s body temp adjusts depending on the environment
osmoconformation
Allowing salt levels to change with environment (strict osmoconformers cannot regulate their salt levels)
osmoregulation
Using energy to regulate internal salt levels (strict regulators maintain a constant salt level no matter what environment)
isosmotic
two areas with same osmotic pressure (concentration solutes)
hypoosmotic
solution of lesser concentration (freshwater is hypoosmotic compared to sea water)
saltwater fish lose water to osmisis because they are hypoosmotic compared to their environment and this must drink more water to compensate for water loss, excrete more concentrated urine, and have transporters that actively transport Cl- and Na+ out of their cells
hyperosmotic
solution of greater concentration (sea water is hyperosmotic compared to freshwater)
freshwater fish are hyperosmotic compared to their surroundings (must take in more salt and excrete dilute urine)
Light curves (incident light vs. photosynthetic rate of plants)
plants in shady environments will plateau sooner as not used to getting much light
Shade vs. Sun leaves
Sun leaves thicker and less broad to fit more photosynthetic machinery and less pigment as sunlight is not the limiting factor
Competitive species
dominate under low disturbance and stress conditions
Ruderals
dominant under conditions of high disturbance and low stress
Stress tolerant
dominant under high stress and low disturbance conditions
