Ecology Lecture Test (1)

Home

the study of relationships of organisms to their environments (biotic and abiotic)

• 1-aquatic insects reflect quality of water
• 2-dust bowls in the 1930s could have been prevented but instead occured via ignorance of ecological principles

• it is based on testable hypotheses
• data are gathered and analyzed
• study can be replicated
• errors can be found and corrected

The inter-relatedness of componets of the system: affecting one thing will affect many

the surroundings of an organism (biotic and abiotic)

the surroundings of an organism (biotic and abiotic)

A sublevel within a habitat

A sand darter (fish) is aquatic, but is found only in flowing water over sand

Aquatic and Terrestrial

The range of variation in which a species can survive

What causes different habitats to support different communities?

Although a species may survive in a range, individuals are usally most successful within a smaller __________.

The _________ for one enbironmental variable may not be obtainable if another important ecological factor doesn't operate at that level.

• 1) Organisms will die, that is, go extrinct, from that area.
• 2)Organisms will survive if they have a stage within their life that can withstand the change (ex: insect pupae)
• 3)Organisms will survive if they can move to a protected microhabitats (ex: herps, bats, rodents in caves or under frost)
• 4)Organisms will survive if it can acclimate

Organisms go extinct from an area. Their population will remain extinct until they can ___________.

A result of shifts outside the range of tolerance

Acclimation is a gradual change into new environmental conditions: aquarium fish placed in a bag for transport

Temporary, Seasonal

A limiting factor or limiting resource is a factor that controls a population's growth, such as organism growth or species population, size, or distribution.

ex: algae phosphate

A limiting factor may be over come through compensation. For example, an organism may prefer cold water, however, if the the O₂ content gets to be too low, that organism may prefer to move to warmer water. It is compensating.

• The combined effects of 2 factors is greater than their sum.
• This can favor or exterminate populations, depending on the effect.

• Are used to communicate information about ecosystems
• Organisms with a narrow tolerance range for some factor of interest

indicator that occurs only within the condition it is meant to indicate (it has good fidelity)

an indicator that is very likely to occur (it is not rare) if the conditions it indicaties are present (it has good constancy)

• Energy is the ability to do work
• Oganism will die.

The laws of thermodynamics

Energy cannot be created or destroyed, only changed in form

in the transfer of energy, some will be lost as heat

lil 'c' calorie.

1 lil 'c' calorie

The Big 'c' Calorie

produce their own food from inorgaic materials

Photosynthetic, Chemosynthetic

Photosynthesis. What does it do?

6CO2 + 6H2O ---> C6H12O6 + 6O2 (by product)

Heterotrophs. What are they?

_________ are organisms that depend on autotrophs for their food (directly and indirectly)

Respiration. What is it?

_________ is the process in which complex molecules are reduced to simple ones, releasing energy tied up in molecular bonds.

2nd law of thermodynamics

2nd law of thermodynamics

• 1] lost as heat
• 2]lost in feces and urine and sweat
• 3]rest is available for work

Assimilated energy

___________ is the energy that is available for work

Standard metabolism

____________ energy used just to stay alive.

Homeothermic

Size

Greater

surface area/volume ratio.

Animal A. Why?

Energy subsidies.

• uses of outside energy to aid an orgaism
• birds use air currents to soar
• fresh water organisms use energy of flowing water

proximate, ultimate

a proximate factor is one that deals with the immediate cause: it is within the organism that you might seek an explanation.

An ultimate factor deals with the grater cause: it is within the environment or population that the answer might be found

movement of individuals from their place of birth

Dispersal

• 1] water
• 2] wind
• 3] animals
• 4] explosive projection

• Larval stages that swim but have sessile adult stages
• Winged stages
• Walking

Fact.

Emigration is the act of leaving one's country or region to settle in another.

• It is dynamic, usually caused by removal of barriers or human action, or environmental change (glacial periods)
• Humans broght starlings to NY, how they're everywhere.
• Humans cut down eastern forests and coyotes moved eastward

This allows fishes to expand ranges. Some event causes the merging of two streams.

• 1]an organism obtains heat from solar radiation, infrared and heat radiation from surroundings, through metabolism, and by convection.
• 2]an organism loses heat by infrared and heat radiation, convection heat loss, and evaporative heat loss (sweat)

for every 10 degrees C greater in temperature there is a 2-3 times greater in rate of chemical processes (Metabolism in an organism)

an organism depends on the environment for heat energy

an organism depends on the environment for heat energy

heat from metabolism warms this type of animal

heat from metabolism warms this type of animal

Advantage

disadvantage, they must spend energy searching for ad food supply to maintain metabolic heat

They are slow in the morning or when it is cold. They could be eaten.

ectotherms

Endotherms

a special strategy in which an endotherm seasonally behaves as an ectotherm.

these organisms go into a deep sleep from which it is very difficult to wake. ex: ground squirrel, wood chucks

bears and other carnivores sometimes enter a deeper-than-normal sleep but they have not dropped body temperatrue as much and can awaken quickly

plants with the ability to grow in xeric (dry) habitats

xerophytes

Plants that are xerophytes but also have the ability to store water in fleshy tissue.

Succulents

• Plants that are xerophytes that also have very long roots to tap into water table
• ex: mesquite root system may reach down 175 feet

phreatophytes

Plants that grow in water so generally there is no problem unless the pond or creek dries.

hydrophytes

CO₂ (not as much is dissolved in water)

These pants usually grow where water is not much of a problem, water conservation adaptations are minimal.

physiologically dry, the salt concentration makes water osmoctically unavailable

Plants that have adaptations that allow them to live the water with high salt concentrations.

Define halophytes

• drinking
• metabolic water
• water from food

• urine
• feces
• evaporation from skin and lungs

• Behavioral-it is active at night when cooler, dig burrows that trap respiratory moisture, seek shade
• Physiological-intestine resorbs water before elimination of feces; loop of Henle in kidneys especially long to resorb water before elimination of urine.

Isotonic

Hypertonic

Hypotonic

• photosynthesis
• vitamin D production
• orientation and perception of the world

ability of plants to survive in reduced light

Define shade tolerance

• Wind break
• Increased humidity
• Moderate temperature

length of light and dark portions of a day - varies seasonally (solstice is long and short, equinox is equal)

The effect of photoperiod is greater in temperate regions because it is more pronounced. Tropical regions use cue like rain fall.

The actual effect of photoperiod is tied to a circadian rhythm - the cycle of responsiveness to stimuli over a 24-hour period.

Soil is a complex system of mineral, organic, gas, water, and living components. It is the balance of these materials that determine the organisms that live there.

• 1]Mechanical weathering
• 2]Chemical weathering
• 3]Bilogical weathering

wind and water crack parent rock

pH factors causing dissolution and leaching

earthworms and other life move material about, aerate or further break up or mix soil

soil formation usually begins from the exposed surface (top), so soil develops a vertical structure called a soil profile, which can be recognized in 3 primary layers.

Soil profile

Topsoil (A horizon), has organic material and weathered mineral material.

B horizon has almost no organic material and less weathered mineral material

C horizon has generally unaltered parent material

The type of parent material determines the kinds of minerals available which may support, or be limiting to, vegetation. Furthermore, the type of vegetation affects soil formation depending on which meneral are absorbed by them.

Texture

Particle size

silt and clay

sandy

Fire is important in the development and maintenance of several ecosystems, naturally started by lightning strikes. Some plants are so adapted as to require fire for successful reproduction. Fire removes vegetation so allows more light to the Fire aids germination of seeds that germinate on bare ground. Fire-darkened souil also absorbs more heat and becomes dries, and erosion may be increased.

fire frequency, dicrection

Surface

They are "cool" , may scorch tree bases, kill some stems, but mostly consumes litter and herbs. They may kill above-ground stems of herbs so these can sprout again from underground parts.

Ground

• ________ fires - subterranean, burns slowly often where there is a thick
• litter - hot, kills most plants, even burns bogs as it dries peat in
• front of it.

Crown

_________ fires - in dense woody vegetation, spreads through canopy killing vegtation from ground up.

The probability of a fire occurring, thus the adaptation of plants to fire frequency.

Fires

relatively frequent fires