Individual

Study of factors affecting an organism at an individual level

(Ex. How much salmon does a brown bear need to eat in order to survive winter on kodiak island?)

long-term trends in weather conditions for a specified time period and region

major driver of environmental conditions (ergo communities)

climate puts selective pressure on organisms

influences the evolution and distribution of organisms

Uneven heating of the earth by sun (LATITUDE AND TILT)

Landforms

Water bodies (oceans, lakes)

Elevation

Circulation of air

Heating of earth's surface and air drives circulation

In tropics: 

sun heats air

warm moist air cools

moisture condenses, forms clouds and heavy rain

Air from tropics stops rising and moves N & S

Sinks to Earth Surface ~ 30° 

Air is dry from dropping rain a tropics, at 30° sucks up moisture and creates deserts

circulates back to tropics

similar to temperate forests and polar deserts

O Horizon

A Horizon

B (Depositional) Horizon

C Horizon

R Horizon

Upper, surface layer is fallen leaves, twigs, and plant material that may be partially fragmented.  Deeper layer is highly fragmented and partially decomposed organic material.

Mix of mineral materials such as clay, silt, and sand and organic matter from the O horizon

Materials leached (organic and inorganic) from the A horizon

Weathered, parent rock material. Weathering produces fragments of the parent rock.

water denser than air (~800x)

reduced effect of gravity/buoyancy

water more viscous than air

large organisms stay suspended

thrust against water

reduced oxygen

1% vs. 20%

Water is universal solvent 

dissolved compounds

Light Availability

photic zone

thermal fluctuation

specific heat water > specific heat of air

< than air

temperature increases

salinity increases

Oxygen decreases (CO₂ increases)

1) Eggs deposited in mud during wet season, diapause (resting) stage for egg during dry season, death of adults, hatching eggs during subsequent wet season

2) Structures to utilize atmosphere O₂ for respiration due to potential for low DO - lungs, gill and mouth chambers, respiring through skin

3) estivation of perennial species- adults have resting stage during dry season

measure of average kinetic temperature

movement of molecules

rates of reactions

photosynthesis

metabolism

regional climate 

reported by NOAA 

climate at scale of cm to km

usually short period of time

elevation

aspect

vegetation

color of the ground, stream bed or water

presence of burrows or boulders

water source

N. Hem

north-facing slope is shaded and cooler (lower evap rates)

south-facing slop has direct sunlight (tilt and latitude)

difference in temp between N & S greaterin winter than summer

Opposite in Southern

provides shading 

lower soil or stream temp

leaf litter provides shading and insulates soil= lower temp

bare ground present at beaches and desert environments

white sand (45 C) vs dark sand (65 C)

Snow and ice reflect more ice than ground or open water

Burrows and underside of rocks generally more stable temperature than surrounding envir

desert animals can use to stay cool in day and warm at night

aquatic less variable to temp thant terrestrial

large bodies of water more stable than small

ground water more stable that runoff driven stream

GW temp = mean annual air temp

in relatively narrow range of conditions

enzymes that control physiological processes have thermal optima

ex:rainbow trout produce two forms of enzyme acetylcholinesterase 

one thermal optima at 2C and one at 17C

varying seasonal temps

physiological change in response to temperature

reversible, short term

temperate fish change to seasonal changes in water temp

H_s = H_m ± H_cd ± H_cv ± H_r - H_e

endos that maintain relatively constant temp

(birds and mammals)

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need to overheating by reducing H_s through conduction, convection and radiation (pg. 111)

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need to stay warm

increase Hs through conduction, convection and radiation 

(pg. 111)

Similar to plants use body shape, size, and pigmentation to regulate temperature

Because animals are more mobile than plants they have increased ability to use behavior to themoregulate. 

-seeking shade

-basking

Pigment – Some grasshoppers can vary Hr during development by changing pigmentation

-grasshoppers developing in cool temps darker than grasshoppers developing in warm temps. 

Orientation to light – The clear-winged grasshopper orients body perpendicular to sun’s rays during cool mornings in order to warm

-In lab could elevate body 12°C above air temp through this behavior.

Use many of the behaviors and have anatomical features to alter temperature exchanges with environment

-E.g., humans are endotherms, but we seek shade or warmth toprevent overheating or hypothermia 

However…Endotherms are very reliant on H_m for maintaining constant temperature

Thermal neutral zone – range of environmental temperatures that endotherm metabolism is consistent

humans in tropical species - origin of species

increase 

cold temps= shiver --> muscle contractions -- > increase metabolism

high temps = increase in metabolism -- > increased heat rate and blood flow to the skin (heat loss through radiation)

Other: licking fur and pantings

Why do endotherms need different adaptations for thermoregulation in water?

Heat loss to water 20x greater in still water and 100x greater in moving water than air.

-breathe air: heat loss is very high at gills of water breathing organisms because of water flowing over capillaries

-abundant insulation: FFF (feathers, fur, and fat)

-countercurrent exchange in extremity to minimize heat loss

Generally large, pelagic fishes

Can use internally generated heat to maintain temperatures in swimming muscles, gut, brain, eyes above ambient temps and at relatively constant temperatures

-Tunas, lamnid sharks, marlins, swordfishes

Maybe 1-14 C > than ambient water temps

Use countercurrent exchange system

Many organisms enter resting stage

maintain appropriate balance of water and dissolved substances because water tends to move from higher to lower concentrations.

active regulation of internal osmotic environment (i.e., maintaining necessary fluid pressure, ion concentrations)

water vapor density (g H₂0/m³)/saturation water vapor density x 100% 

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Hypoosmotic to environment 

Issues

-Water loss due to high salt concentration of sea water

-Ions diffuse into fish thorough permeable membranes

Dealing with water loss:

-Drink water

-Recover water from urine in bladder

-Reduced glomerulus to conserve water

Dealing with excess ions:

-Actively export ions through chloride cells in gills

-Excrete concentrated urine

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Hyperosmotic to environment (greater solute concentration in body than surrounding water)

Gain water through gills and membranes in pharynx

Lose solutes through gills and membranes in pharynx

Lose solutes in urine

Dealing with loss of solutes:

-Actively transport Na and Cl ions into body through gills usingchloride cells

-Recover some solutes from urine and actively transport to blood 

Dealing with excess water:

-Drink very little water

-Well developed glomerulus in kidney

-Excrete large volumes of dilute urine

fish that spend portions of their life cycles partially in fresh water and partially in salt wate

Must be able to make adjustments based on different osmotic environments

Increased ability to make adjustments to chloride cells in gill epithelium

From soil->plants->atmosphere water moves down a water potential gradient 

-water potential (ψ)-difference inpotential energy between purewaterand a particular water sample (e.g.,difference in potential energy of purewater vs water in leaves of a tree) 

-water potential measured inmegapascals (Mpa)

Water potential of pure water = 0; water potential generally negative in nature

Water moves up in a plant because water potential is lower in the leaves and top of a plant compared to the roots

W_ip = W_r + W_a – W_t – W_s 

Roots much more extensive due to need for increased surface area to take up water from soil

-biomass of roots may constitute 90% of plant 

Roots often extend further into the soil to potentially reach groundwater

-taproots of some desert shrubs extend 9-30 m into soils!

W_ia = W_d + W_f + W_a – W_e – W_s

In addition to consuming more water, water budgets can be balanced by reducing water loss

Organisms that evolved in drier climates more resistant to desiccation than organisms that evolved in moist climates

Animals restrict activity times to limit water loss (nocturnal)

Produce concentrated urine or feces with low moisture

-e.g., kangaroo rats of kidney with long loop of henle to reabsorbwater and concentrate urine

-e.g., moisture in feces absorbed in large intestine

Use water produced during metabolism

Long mucus-lined nasal passages to capture moisture from air being exhaled

Lack sweat glands 

Fur – prevents from evaporation

Mechanisms for

(1)reducing water loss through evaporation,

(2) reducing heat gain,

(3) storing water or sources of water,

(4) consuming large quantities of water when available

light, inorganic molecules, and organic molecules.

Photosynthetically active radiation

(PAR)

Visible light is the light used for photosynthesis

Infrared (not enough energy)

Ultraviolet (too much energy)

Measured as photon flux density – number of photons striking a square meter per second

Measured in μmol

1. Photosynthetic pigments absorb photons from sunlight 
2. Energy transferred to electrons
3. Energy in electrons used to synthesize ATP and NADPH
4. ATP and NADPH donate electrons and energy for production of sugar
5. Sugar can be used to synthesize proteins, fatty acids, enzymes

most common

CO2 combines with ribulose biphosphate (RuBP) to create three-carbon (hence the name C3) phosphoglyceric acid

-catalyzed by enzyme RuBP carboxylase

To get CO2 need to open stomata

-this causes issue of releasing water vapor

Problem is increased because RuBP carboxylase has low affinity for CO2, 

= low CO2 rate of uptake

= stomata needing to stay open longer

Separates carbon fixation (reactions where CO₂ becomes incorporated into carbon-containing acids) and light-dependent reactions; occur in different cells

CO2 combines with phosphenol pyruvate (PEP) to form four-carbon acid (hence “C4”)

-this is fixation step

-catalyzed by enzyme PEP carboxylase (see thetrend…carboxylases catalyze fixation)

-PEP carboxylase has a high affinity for CO₂ (unlike RuBPcarboxylase)

Corn, about 50% of grass species

Crassulacean acid metabolism (CAM)

Succulent plants in arid and semi-arid environments

Carbon-fixation occurs at night

-Cooler--> less evap

CO₂ combines with PEP to form four-carbon acid

Acids stored until daylight, then broken down into CO₂ and pyruvate

-enter C3 photosynthesis cycle 

Photosynthesis does not occur at high rate, but efficient water use (higher efficiency than C3 and C4)

Relatively recently discovered (late 1970’s)

First discovered around underwater volcanoes

Base of foodweb is photosynthetic bacteria

Volcanoes discharge sulfide-rich water

Autotrophic bacteria oxidize sulfur, H2S, or thiosulfate to get energy 

CO₂ as carbon source

Although stationary plants have defenses that herbivores must overcome

Physical defenses: thorns (pain), silica in grass tissues (wear down teeth), cellulose and lignin (make plant tough and decrease nutritional value)

Chemical defenses: Alkaloid based toxins (give bitter taste; nicotine, cocaine)

-higher proportion of tropical plants contain alkaloids and producemore toxic alkaloids than temperate plants

-tropical plants grazed more heavily = greater selective pressure for defense 

Plant defenses do not work universally

“Predator-Prey” arms race

As plants evolved defenses, herbivores evolved and vice versa

Some insects convert toxic alkaloids into non-toxic chemicals

Giraffe tongue

Consume dead organic material, mostly plants (helps break plant material into smaller and smaller fragments)

Important for nutrient cycling 

Same issue as herbivores…low N in dead plants

Dead plant material has even less N than living plant tissue!

Many organisms look similar or have similar color patterns as other species that are toxic or “dangerous” to predators.

noxious species (“dangerous”) mimici each other

-E.g., two venomous snakes mimicking each other

harmless species mimics noxious species

Diet studies common in ecological literature

Understanding of bioenergetics

Effects of invasive species (predators and prey)

Energy flow and food webs

What organisms eat can substantially affect on life history (growth, longevity, age-at-maturity, fecundity)

fecundity: how many eggs a female produces in season/lifetime?

Predators frequently select prey based on size

Size of prey often correlated with size of predator

(1) availability of energy

(2) ability to process energy

 P_max 

maximum photosynthesis rate given that not limited by:

-nutrients,

-water,

-CO₂

-temperature,

-humidity

P_max can vary among plants from different environments 

Some desert plants have high P_max

-in order to be able to produce a lot of food during the infrequent times when water is available

Developed by increasing the amount of food available an animal and measuring foot intake/time.

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Type I – only observed for animals that have little or no processing time for handling prey (small prey). E.g., aquatic filter feeders

Type II – At low prey density, feeding rate limited by finding food.  Intermediate density, limited by finding food and handling food. High density, limited by handling time.

Type III – Learning rate for new prey or multiple prey types.