BIOL 4120: Principles of EcologyBIOL 4120: Principles of Ecology

Lecture 7: Animal adaptations to Lecture 7: Animal adaptations to the Environmentthe Environment

Dafeng HuiDafeng Hui

Office: Harned Hall 320Office: Harned Hall 320

Phone: 963-5777Phone: 963-5777

Email: dhui@tnstate.eduEmail: dhui@tnstate.edu

TopicsTopics7.1 Animals have various ways to acquire energy and nutrients7.1 Animals have various ways to acquire energy and nutrients7.2 Animals have various nutritional needs7.2 Animals have various nutritional needs7.3 Animal require oxygen to release energy contained in food7.3 Animal require oxygen to release energy contained in food7.4 Regulation of internal conditions involves homeostasis and 7.4 Regulation of internal conditions involves homeostasis and

feedbackfeedback7.5 Animals have different methods of maintaining their body 7.5 Animals have different methods of maintaining their body

temperaturestemperatures7.6 Poikilotherms depend on environmental temperatures7.6 Poikilotherms depend on environmental temperatures7.7 Homeotherms escape the thermal restraints of the environment7.7 Homeotherms escape the thermal restraints of the environment7.8 Endothermy and Ectothermy involve trade-offs7.8 Endothermy and Ectothermy involve trade-offs7.9 Heterotherms take on characteristics of ectotherms and 7.9 Heterotherms take on characteristics of ectotherms and

endothermsendotherms7.10 Torpor helps some animals conserve energy7.10 Torpor helps some animals conserve energy7.11 Some animals use unique physiological means for thermal 7.11 Some animals use unique physiological means for thermal

balancebalance7.12 Maintenance of water balance7.12 Maintenance of water balance7.13 Biological clocks influence animal activity7.13 Biological clocks influence animal activity

Animals are heterotrophs and derive their energy Animals are heterotrophs and derive their energy and most nutrients from consuming organic and most nutrients from consuming organic compounds contained in other plants and animalscompounds contained in other plants and animals

Key processes common to all animalsKey processes common to all animals• Acquire and digest foodAcquire and digest food• Absorb oxygenAbsorb oxygen• Maintain body temperature and water balanceMaintain body temperature and water balance• Adapt to light and temperature variationsAdapt to light and temperature variations

Animals encounter different constraints in aquatic Animals encounter different constraints in aquatic versus terrestrial environmentsversus terrestrial environments

Chapter 7 Animal Adaptations to the Chapter 7 Animal Adaptations to the EnvironmentEnvironment

7.1 Animals have various ways of 7.1 Animals have various ways of acquiring energy and nutrientsacquiring energy and nutrients

Energy sources for plants and animalsEnergy sources for plants and animals Three Feeding Methods of Heterotrophs:Three Feeding Methods of Heterotrophs:

• Herbivores: Feed on plants.Herbivores: Feed on plants.• Carnivores: Feed on animal flesh.Carnivores: Feed on animal flesh.• Omnivores: Feed on both plants and animalsOmnivores: Feed on both plants and animals• Detritivores:Detritivores: Feed on non-living organic matter Feed on non-living organic matter

(earthworm, dung beetle).(earthworm, dung beetle).

Animals have various ways of Animals have various ways of acquiring energy and nutrientsacquiring energy and nutrients

Mouthparts Mouthparts reflect how reflect how organisms obtain organisms obtain their food.their food.

Herbivores Herbivores • Grazers (cattle, dear, sheep, grasshopper)Grazers (cattle, dear, sheep, grasshopper)

Leafy material (Ruminants chew the cud; Non ruminants Leafy material (Ruminants chew the cud; Non ruminants are less efficient)are less efficient)

High in cellulose and some lignin (C:N ratio)High in cellulose and some lignin (C:N ratio)• Use specialized microorganisms in gut to help digest the Use specialized microorganisms in gut to help digest the

difficult carbohydrate molecules in ruman or cecum or difficult carbohydrate molecules in ruman or cecum or redigestion (redigestion (FermentationFermentation))

• Microorganisms produce proteins, lipids etcMicroorganisms produce proteins, lipids etc

• BrowsersBrowsers Woody material (Termites)Woody material (Termites)

• High in lignin and celluloseHigh in lignin and cellulose• Use specialized microorganisms in gut to help digest the Use specialized microorganisms in gut to help digest the

difficult carbohydrate moleculesdifficult carbohydrate molecules• Microorganisms produce proteins, lipids etcMicroorganisms produce proteins, lipids etc

• Granivores (birds)Granivores (birds) SeedsSeeds

• Crop with specialized enzymesCrop with specialized enzymes• Gizzard for grindingGizzard for grinding

• Frugivores (monkey etc.)Frugivores (monkey etc.) FruitFruit

CarnivoresCarnivores• First level feed directly on herbivoresFirst level feed directly on herbivores

No celluloseNo cellulose Rapid digestion and easy assimilationRapid digestion and easy assimilation Hunting is energy consumingHunting is energy consuming

• Second level feed on first level carnivoresSecond level feed on first level carnivores OmnivoresOmnivores

• Food eating habits vary with season, life cycle Food eating habits vary with season, life cycle and their sizesand their sizes

FoxFox• Preferential carnivorePreferential carnivore

Insects, small mammals and birdsInsects, small mammals and birds but eats berries, fruit, grassbut eats berries, fruit, grass

BearBear• Preferential herbivorePreferential herbivore

Buds, leaves, berries, fruit, etcBuds, leaves, berries, fruit, etc Supplemented by insects, fish and small to medium Supplemented by insects, fish and small to medium

mammalsmammals

Red Fox is an Red Fox is an example of example of an omnivorean omnivore

7.2 Animals have various nutritional 7.2 Animals have various nutritional needsneeds

Animals need amino acids and specific minerals such as sodium, Animals need amino acids and specific minerals such as sodium, calcium, magnesium, etccalcium, magnesium, etc

High quality and quantity of plants are very important to animal High quality and quantity of plants are very important to animal survivalsurvival

Herbivores show certain preference on high N plants (Taste and Herbivores show certain preference on high N plants (Taste and odor)odor)

Deficiency in minerals influences distribution, behavior, and Deficiency in minerals influences distribution, behavior, and physiology of animalsphysiology of animals

Sodium can be hard to obtain and can be a problemSodium can be hard to obtain and can be a problem• Kangaroos, Rabbits in AustraliaKangaroos, Rabbits in Australia

Overgrazing of sodium rich plants can cause population collapse (plants died)Overgrazing of sodium rich plants can cause population collapse (plants died)• ElephantsElephants

See preference for sodium rich water hole in Wankie National Park, ZimbabweSee preference for sodium rich water hole in Wankie National Park, Zimbabwe Dear: eating mineral-rich soil in springDear: eating mineral-rich soil in spring

High potassium in spring vegetation may cause calcium, magnesium High potassium in spring vegetation may cause calcium, magnesium deficiency in goats, cattle and sheep (influence hormone balance)deficiency in goats, cattle and sheep (influence hormone balance)

Nutrient conditions influence growth and reproduction.Nutrient conditions influence growth and reproduction.

Deer need lots Deer need lots of calcium, of calcium, phosphorus and phosphorus and protein to grow protein to grow antlers, which antlers, which are needed for are needed for reproductive reproductive successsuccess• Deficiency Deficiency

results in results in stunted antlersstunted antlers

7.3 Animals require oxygen7.3 Animals require oxygen Energy from organic compounds in the food they Energy from organic compounds in the food they

eateat Release energy primarily through aerobic Release energy primarily through aerobic

respirationrespiration O2 is required (could be an issue for aquatic O2 is required (could be an issue for aquatic

animals)animals) Methods to acquire O2Methods to acquire O2

• Body surface: insects, tracheal tubesBody surface: insects, tracheal tubes• Lungs: mammals, birds, reptilesLungs: mammals, birds, reptiles• Lung and air sacs: birdsLung and air sacs: birds• Lungs: whales and sharksLungs: whales and sharks• Gills: FishGills: Fish

Respiration systemsRespiration systemsAnimals need to use aerobic Animals need to use aerobic

respirationrespiration Therefore need to have Therefore need to have

excellent oxygen uptake excellent oxygen uptake systemsystem

Small animalsSmall animals• DiffusionDiffusion

InsectsInsects• Diffusion and spiraclesDiffusion and spiracles

AmphibiansAmphibians• Vascularised skinVascularised skin• Simple lungsSimple lungs

MammalsMammals• LungsLungs

BirdsBirds• LungsLungs• Anterior and posterior air sacsAnterior and posterior air sacs

FishFish• GillsGills

Aquatic mammalsAquatic mammals• LungsLungs• Special haemoglobin oxygen storage Special haemoglobin oxygen storage

systemssystems

O2 countercurrent exchangeO2 countercurrent exchange

BIOL 4120: Principles of EcologyBIOL 4120: Principles of Ecology

Lecture 7: Animal adaptations to Lecture 7: Animal adaptations to the Environmentthe Environment

Dafeng HuiDafeng Hui

Office: Harned Hall 320Office: Harned Hall 320

Phone: 963-5777Phone: 963-5777

Email: dhui@tnstate.eduEmail: dhui@tnstate.edu

7.4 Regulation of internal conditions 7.4 Regulation of internal conditions involves homeostasis and feedbackinvolves homeostasis and feedback

Homeostasis:Homeostasis: The maintenance of a The maintenance of a relatively constant internal environment in relatively constant internal environment in a varying external environment.a varying external environment.

Homeostasis depends on negative feedbackHomeostasis depends on negative feedbackNegative feedback:Negative feedback: when a system when a system

deviates from the normal or desired state, deviates from the normal or desired state, mechanisms function to restore the mechanisms function to restore the system back to that state.system back to that state.

Example: room temperature settingExample: room temperature setting

HomeostasisHomeostasis To stay alive, animals To stay alive, animals

need to keep their body need to keep their body within certain limitswithin certain limits• TemperatureTemperature• Water balanceWater balance• pHpH• Salt balanceSalt balance

Feedback systems to Feedback systems to help to keep within help to keep within specific limitsspecific limits

Outside limits Outside limits –– • DehydrationDehydration• Heat shockHeat shock• Salt imbalanceSalt imbalance• DeathDeath

Negative feedback (thermoregulation)

Body structure influences Body structure influences the T exchangethe T exchange

Temperature (Tb, Ts, Ta)Temperature (Tb, Ts, Ta) Tb<->Ts conductionTb<->Ts conduction

• Boundary layer (a thin layer Boundary layer (a thin layer of air surround the body)of air surround the body)

• Core temperature TbCore temperature Tb• Surface temperature TsSurface temperature Ts

EarsEars FingersFingers ToesToes

Ts<->Ta: conduction, Ts<->Ta: conduction, convection, radiation, convection, radiation, evaporationevaporation

Insulation (air, body Insulation (air, body covering) influences energy covering) influences energy exchangesexchanges

Animals exchange energy with their surrounding environment

7.5 Animals have different methods of 7.5 Animals have different methods of maintaining their body temperaturesmaintaining their body temperaturesThree groups of animalsThree groups of animals Endothermy resulting in homeothermyEndothermy resulting in homeothermy

• Use of internal heat source (metabolically)Use of internal heat source (metabolically) Mammals and birdsMammals and birds Maintain a fairly constant temperature (warm-blooded)Maintain a fairly constant temperature (warm-blooded)

Ectothermy resulting in poikilothermyEctothermy resulting in poikilothermy• Use of external heat sourcesUse of external heat sources

Reptiles, amphibians, fish, insects and invertebratesReptiles, amphibians, fish, insects and invertebrates Results in a variable body temperature (cold-blooded)Results in a variable body temperature (cold-blooded)

HeterothermHeterotherm• Uses both endothermy and ectothermyUses both endothermy and ectothermy

Bats, bees and hummingbirdsBats, bees and hummingbirds Depends on environmental situations and metabolic needs.Depends on environmental situations and metabolic needs.

• As the temperature As the temperature increases, so does the increases, so does the metabolic ratemetabolic rate

• Therefore these animals Therefore these animals are more active during the are more active during the dayday

• Every 10Every 10ooC doubles C doubles metabolic ratemetabolic rate

• Naturally low metabolic Naturally low metabolic rate and high conductivityrate and high conductivity

• Activities also control Activities also control temperaturetemperature

• Upper and lower limits varyUpper and lower limits vary Lizards and snakes have a Lizards and snakes have a

55ooCC Amphibians have a 10Amphibians have a 10ooCC

7.6 Poikilotherms depend on 7.6 Poikilotherms depend on environmental temperaturesenvironmental temperatures

Operative T range: range of body T at which poikilotherms can carry out their daily activities (next slide).

During the day, the snake During the day, the snake can maintain a fairly can maintain a fairly constant temperature by constant temperature by adjusting itadjusting it’’s environment s environment (bask in sun to raise T, (bask in sun to raise T, seek shade to cool, seek shade to cool, submerge in water etc)submerge in water etc)

During the night, it has few During the night, it has few optionsoptions• Temperature drops 10-Temperature drops 10-

15 degrees15 degrees• Become torpid (slow Become torpid (slow

moving)moving)• Restricted by Restricted by

environmentenvironment• Limited to Maximum size Limited to Maximum size

due to need for surface due to need for surface area to gather heatarea to gather heat

• No minimum sizeNo minimum size

Poikilotherms in waterPoikilotherms in water• No insulationNo insulation• Match of body temperature to water temperatureMatch of body temperature to water temperature• Water temperature normally only changes slowly Water temperature normally only changes slowly

with seasonwith season• Poikilotherms can adjust slowly to a wide range Poikilotherms can adjust slowly to a wide range

of temperatures than land poikilotherms of temperatures than land poikilotherms ((acclimationacclimation))

• Stressed by rapid temperature changesStressed by rapid temperature changes

7.7 Homeotherms escape the thermal 7.7 Homeotherms escape the thermal restraints of the environmentrestraints of the environment

Homeotherms can escape the thermal Homeotherms can escape the thermal restraints of the environments, thus restraints of the environments, thus can exploit a wide range of thermal environments

But needs energy to maintain relative But needs energy to maintain relative constant Tconstant T

Therefore homeotherms use large amounts Therefore homeotherms use large amounts of glucose etc to maintain temperature of glucose etc to maintain temperature (aerobic respiration)(aerobic respiration)

O2 is consumed during respirationO2 is consumed during respiration Rate of O2 consumption is used to measure Rate of O2 consumption is used to measure

metabolic ratemetabolic rate

Resting metabolic rate and ambient Resting metabolic rate and ambient temperaturetemperature

Thermoneutral zone: a range of environmental temperatures within which the metabolic rates are minimal.

Critical T: lower and upper critical T

Homeotherms can escape the thermal Homeotherms can escape the thermal constraints of the environmentsconstraints of the environments

Ways to keep body warm: Ways to keep body warm: 1. Insulation to reduce the convection: fur, feather, or body fat1. Insulation to reduce the convection: fur, feather, or body fat Mammals: fur, change fur in the winterMammals: fur, change fur in the winter

Fur can keep body heat in and the Fur can keep body heat in and the heat outheat out Birds: featherBirds: feather Insects: a dense fur-like coat (moths, bees)Insects: a dense fur-like coat (moths, bees)2. When insulation fails: shivering (a form of involuntary 2. When insulation fails: shivering (a form of involuntary

muscular activity that increase heat production.muscular activity that increase heat production.3. Small mammals: burn brown fat (bats) without shivering.3. Small mammals: burn brown fat (bats) without shivering.

Ways to keep body Cool:Ways to keep body Cool:1. birds and mammals: evaporation of moisture from skin1. birds and mammals: evaporation of moisture from skin2. mammals: sweat glands (horse, human), panting2. mammals: sweat glands (horse, human), panting3. birds: gular fluttering3. birds: gular fluttering

7.8 Endothermy and Ectothermy involve 7.8 Endothermy and Ectothermy involve trade-offstrade-offs

New Scientist, 2009

7.8 Endothermy and Ectothermy involve 7.8 Endothermy and Ectothermy involve trade-offstrade-offs

Endotherms can survive in large range of T, Endotherms can survive in large range of T, why not all animals are endotherms?why not all animals are endotherms?

EndothermsEndotherms EctothermsEctothermsActivity: under all environments limited to environmental TActivity: under all environments limited to environmental TEnergy: high lowEnergy: high lowFood: most for respiration, less less for respirationFood: most for respiration, less less for respiration to growth more to growthto growth more to growthLimits on size:Limits on size: limit on minimum size limit on maximum size limit on minimum size limit on maximum size

Limited in sizeLimited in size

Warm-blooded animals: body Warm-blooded animals: body mass (volume) produce mass (volume) produce heat, lost through surface heat, lost through surface area, the ratio of surface to area, the ratio of surface to volume is key factor too.volume is key factor too.• Small animals have Small animals have

larger ratio and greater larger ratio and greater relative heat loss to relative heat loss to environment, require environment, require higher mass-specific higher mass-specific metabolic rate to metabolic rate to maintain and consume maintain and consume more food energy per more food energy per unit body weight. unit body weight.

• Too smallToo small Need too much Need too much

energy to keep energy to keep temperature stabletemperature stable

2 gm limit2 gm limit Shrew (SolexShrew (Solex spp) spp)

eats own body eats own body weight in food every weight in food every day to maintain day to maintain temperaturetemperature

Cold-blooded animals absorb heat through surface, thus the surface area to volume is also a key factor. Large animals limited to warm areas.

Metabolic rate and body massMetabolic rate and body mass

7.9 Heterotherms take on characteristics 7.9 Heterotherms take on characteristics of ectotherms and endothermsof ectotherms and endotherms

Temporal heterotherms: species that sometimes Temporal heterotherms: species that sometimes regulate their body T and sometimes they do not.regulate their body T and sometimes they do not.

Insects, bats, bees, hummingbirdsInsects, bats, bees, hummingbirds

Adult insects can be ectothermic and Adult insects can be ectothermic and endothermic: endothermic:

T limits on flight: 30oC for take off, and no T limits on flight: 30oC for take off, and no more than 40oC for flightmore than 40oC for flightNeed warm-up to take off: ectothermicNeed warm-up to take off: ectothermicFlight: burn energy, endothermicFlight: burn energy, endothermic

7.10 Torpor helps some animals 7.10 Torpor helps some animals conserve energyconserve energy

TorporTorpor• Small homeothemic animalsSmall homeothemic animals

Become heterothermicBecome heterothermic Body temperature drops to ambient at nightBody temperature drops to ambient at night InactiveInactive

• Bats, Some mice, kangaroosBats, Some mice, kangaroos HibernationHibernation

• Many poikilotherms and some mammals have winter torpor to Many poikilotherms and some mammals have winter torpor to save energysave energy

• Selective advantage when resources are fewSelective advantage when resources are few• MammalsMammals

Heart rate, respiration fallHeart rate, respiration fall Temperature drops to ambientTemperature drops to ambient Groundhogs, chipmonksGroundhogs, chipmonks Not bearsNot bears

• No temperature changeNo temperature change• Just long sleep with no eating, drinking, defecating or urinatingJust long sleep with no eating, drinking, defecating or urinating• Females give birth and feed young in this periodFemales give birth and feed young in this period• Can wake up easilyCan wake up easily• Do not visit a bear cave in winter!Do not visit a bear cave in winter!

7.11 Some animals use unique physiological 7.11 Some animals use unique physiological means for thermal balancemeans for thermal balance

Storing body heat: Storing body heat:

Camel, oryx and some gazelles Camel, oryx and some gazelles

Body T change from 34oc to 41oC for camel (morning to Body T change from 34oc to 41oC for camel (morning to afternoon)afternoon)

Reduce need for evaporative cooling and save water and energyReduce need for evaporative cooling and save water and energy

Supercooling:Supercooling:

many ectothermic animals of temperate and Arctic regionsmany ectothermic animals of temperate and Arctic regions

When the body T below freezing points without actually freezingWhen the body T below freezing points without actually freezing

The presence of certain solute (glycerol) in the body lower the The presence of certain solute (glycerol) in the body lower the freezing pointsfreezing points

Wood frog, grey tree frog, spring peeperWood frog, grey tree frog, spring peeper

Countercurrent heat exchange:Countercurrent heat exchange:to conserve heat in a cold environment and to cool vital part of to conserve heat in a cold environment and to cool vital part of body during heat stress.body during heat stress.

Countcurrent heat exchange happens in Countcurrent heat exchange happens in homeotherms (porpoise, whale) as well as in certain homeotherms (porpoise, whale) as well as in certain poikilotherms (tuna, mackerel shark)poikilotherms (tuna, mackerel shark)

To preserve heat in cold water, and get ride of heat in warm water

To cool brain, reduce T by 2-3oC

7.12 Maintenance of water balance7.12 Maintenance of water balance TerrestrialTerrestrial

• InputInput DrinkingDrinking EatingEating Produced by metabolism (respiration)Produced by metabolism (respiration)

• Output Output –– Need to control in extreme Need to control in extreme environments environments

UrineUrine• Concentrated to avoid water lossConcentrated to avoid water loss

FecesFeces EvaporationEvaporation

• No sweat glands in some mammalsNo sweat glands in some mammals BreathingBreathing

What happens to ungulates in a hot What happens to ungulates in a hot dry climate like Africadry climate like Africa

No pants, no sweating to save water, store heat in body (T up to 46oC at daytime, release heat at night 36oC)

Countcurrent heat exchange to lower head T

Eat at nighttime, more water in plants

Respiration to produce water

Maintenance of water balanceMaintenance of water balance AquaticAquatic

• Freshwater (hyperosmotic, high salt in Freshwater (hyperosmotic, high salt in body)body)

• Prevent excess uptake of waterPrevent excess uptake of water Remove excess waterRemove excess water

• Retain salt in special cells (gills)Retain salt in special cells (gills)• Large amounts of very dilute urineLarge amounts of very dilute urine

• Saltwater (hypoosmotic, low salt in body)Saltwater (hypoosmotic, low salt in body) If salt concentration is higher than in body, If salt concentration is higher than in body,

dehydratedehydrate• Ion pumps, gill (fish)Ion pumps, gill (fish)• Kidneys (eliminate salts, marine mammals)Kidneys (eliminate salts, marine mammals)• Salt secreting glands in birdsSalt secreting glands in birds

Buoyancy aids aquatic organisms to stay Buoyancy aids aquatic organisms to stay afloatafloat

Gas or swim bladder (most fish)Gas or swim bladder (most fish)• 5-10% body volume5-10% body volume

Lungs in air-breathing animalsLungs in air-breathing animals Replace heavy chemical ions in the Replace heavy chemical ions in the

body fluids with lighter onesbody fluids with lighter ones• Squid (ammonium ions to replace sodium Squid (ammonium ions to replace sodium

ions)ions)• Shark, mackerels, bluefish: store lipids Shark, mackerels, bluefish: store lipids

(less dense than seawater)(less dense than seawater)

Aquatic animals Aquatic animals need to move up need to move up and down in waterand down in water

Buoyancy aidsBuoyancy aids SharkShark

• Large fatty Large fatty liverliver

• Must swim to Must swim to not sinknot sink

FishFish• Gas bladderGas bladder• Used to move Used to move

up and downup and down SealSeal

• BlubberBlubber• Can float on Can float on

surface with surface with air in lungsair in lungs

7.13 Biological clocks influence animal 7.13 Biological clocks influence animal activityactivity

Daily and seasonal light and dark Daily and seasonal light and dark cyclescycles

Critical daylengths trigger seasonal Critical daylengths trigger seasonal responsesresponses

Activity rhythms of intertidal Activity rhythms of intertidal organisms follow tidal cyclesorganisms follow tidal cycles

Animals react to changing light through internal Animals react to changing light through internal biological clocksbiological clocks

Internal Biological Clocks have adaptive valueInternal Biological Clocks have adaptive value• Used to change behavior: feeding, food storage, Used to change behavior: feeding, food storage,

reproduction, migration.reproduction, migration. Daily (Circadian rhythm): sleep, metabolic rate, Daily (Circadian rhythm): sleep, metabolic rate,

temperaturetemperature

Predators must match their feeding activity with Predators must match their feeding activity with prey. prey.

Seasonal: food storage, migrationSeasonal: food storage, migration

Seasonal Seasonal Changes for Changes for male deermale deer

Only needed Only needed during mating during mating seasonseason

Can be Can be damaged and damaged and need need replacingreplacing

Critical daylengths trigger seasonal responsesCritical daylengths trigger seasonal responses

Squirrels start activity when the day starts, regardless of Squirrels start activity when the day starts, regardless of the seasonthe season

Daylengths influence organisms activityDaylengths influence organisms activity

Critical daylengthCritical daylength• Duration of light or dark reaches a certain proportion of the 24-Duration of light or dark reaches a certain proportion of the 24-

hour day, it inhibits or promotes a photoperiodic response. hour day, it inhibits or promotes a photoperiodic response. • Normally 10-14 hoursNormally 10-14 hours

Day-neutral organisms: not controlled by daylengthDay-neutral organisms: not controlled by daylength Short-day organisms: reproduction (or other activity) is Short-day organisms: reproduction (or other activity) is

stimulated by daylength shorter than critical daylengthstimulated by daylength shorter than critical daylength Long-day organisms: ~longer~Long-day organisms: ~longer~

Diapause: a stage of arrested growth over winter in insects of Diapause: a stage of arrested growth over winter in insects of the temperate regions controlled by photoperiod.the temperate regions controlled by photoperiod.• Requirement: 12-13 hours of lightRequirement: 12-13 hours of light• A quarter-hour difference can determine diapause or notA quarter-hour difference can determine diapause or not

Crabs from a tidal estuary Crabs from a tidal estuary retain timed activities in a retain timed activities in a fixed environmentfixed environment• Color change (day and night)Color change (day and night)• Activity (tides)Activity (tides)• Two clocksTwo clocks

TidalTidal SolarSolar

Activity rhythms of intertidal Activity rhythms of intertidal organisms follow tidal cyclesorganisms follow tidal cycles

The ENDThe END

Circadian (24 hr) rhythm Circadian (24 hr) rhythm is very important to is very important to most living organismsmost living organisms

Timing measuresTiming measures• LightLight• TemperatureTemperature• MoistureMoisture

Temperate zoneTemperate zone• Light cycleLight cycle

Arctic and subarctic Arctic and subarctic zoneszones• TemperatureTemperature

Tropical and subtropical Tropical and subtropical zoneszones• MoistureMoisture

Water Movement in Aquatic Water Movement in Aquatic EnvironmentEnvironment

Isomotic (isotonic)Isomotic (isotonic): Body fluids and : Body fluids and external fluid are at the same external fluid are at the same concentration.concentration.

Hypoosmotic (hypotonic)Hypoosmotic (hypotonic): Body fluids : Body fluids are at a lower concentration of salt are at a lower concentration of salt than the external environment.than the external environment.

Hyperosmotic (hypertonic)Hyperosmotic (hypertonic): Body fluids : Body fluids are at a higher salt concentration than are at a higher salt concentration than the external environment. (freshwater)the external environment. (freshwater)

Fig. 5.4

Digestive systems are different for these different type of animals

Stomach

Caecum:

Intestine

Colon