EcologyEcology

Lecture 6Lecture 6

Ralph KirbyRalph Kirby

Adaptation of Animals to their Adaptation of Animals to their environmentenvironment

The environments on Earth The environments on Earth vary greatly. See earlier vary greatly. See earlier lectureslecturesTherefore animals (and all Therefore animals (and all other living organisms) other living organisms) need to adapt to fit their need to adapt to fit their environmentenvironment|Obtaining nutrients is |Obtaining nutrients is probably one of the most probably one of the most importantimportant– Input into system is the Input into system is the

plantsplants– Plants consumed by Plants consumed by

herbivoresherbivores– Herbivore animals eaten Herbivore animals eaten

by carnivoresby carnivores– Omnivores use both Omnivores use both

sources but may have a sources but may have a preferred onepreferred one

HerbivoresHerbivores– Grazers (Ruminants)Grazers (Ruminants)

Leafy materialLeafy materialRuminants chew the cudRuminants chew the cudNon ruminants are less efficientNon ruminants are less efficientCoprophagyCoprophagy

– High in cellulose and some ligninHigh in cellulose and some lignin– Use specialized microorganisms in gut to help digest the difficult Use specialized microorganisms in gut to help digest the difficult

carbohydrate molecules in ruman or cecum or redigestioncarbohydrate molecules in ruman or cecum or redigestion– Microorganisms produce proteins, lipids etcMicroorganisms produce proteins, lipids etc

– BrowsersBrowsersWoody materialWoody materialTermitesTermites

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

carbohydrate moleculescarbohydrate molecules– Microorganisms produce proteins, lipids etcMicroorganisms produce proteins, lipids etc

– GranivoresGranivoresSeedsSeeds

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

– FrugivoresFrugivoresFruitFruit

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

No celluloseNo celluloseRapid digestion and easy assimilationRapid digestion and easy assimilationHunting 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 and Food eating habits vary with season, life cycle and

their sizetheir sizeFoxFox

– Preferential carnivorePreferential carnivoreInsects, small mammals and birdsInsects, small mammals and birdsbut eats berries, fruit, grassbut eats berries, fruit, grass

BearBear– Preferential herbivorePreferential herbivore

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

Animals needAnimals need– Essential amino acids Essential amino acids

(14)(14)– Other amino acidsOther amino acids– MineralsMinerals

Herbivores need high Herbivores need high nitrogen help nitrogen help microorganisms in microorganisms in the digestion of the digestion of cellulose and lignincellulose and ligninHowever, season is However, season is very importantvery importantHerbivores get more Herbivores get more high nitrogen food in high nitrogen food in Spring and therefore Spring and therefore they reproduce at they reproduce at that timethat timeAvailability is very Availability is very important for a important for a carnivore or carnivore or omnivoreomnivore

MineralsMinerals

Animals need specific minerals such as sodium, Animals need specific minerals such as sodium, magnesium, etcmagnesium, etcSodium can be hard to obtain and can be a Sodium can be hard to obtain and can be a problemproblem– KangaroosKangaroos– Rabbits in AustraliaRabbits in Australia

Overgrazing of sodium rich plants can cause population Overgrazing of sodium rich plants can cause population collapsecollapse

– ElephantsElephantsSee preference for sodium rich water hole in Wankie See preference for sodium rich water hole in Wankie National Park, ZimbabweNational Park, Zimbabwe

High potassium can cause magnesium High potassium can cause magnesium deficiency in goats, cattle and sheepdeficiency in goats, cattle and sheep

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

in stunted antlersin stunted antlers

Animals need to use Animals need to use aerobic respirationaerobic respirationTherefore need to have Therefore need to have excellent oxygen uptake excellent oxygen uptake systemsystemSmall animalsSmall animals– DiffusionDiffusion

InsectsInsects– Diffusion and spiraclesDiffusion and spiracles

AmphibiansAmphibians– Vascularised skinVascularised skin– Simple lungsSimple lungs

MammalsMammals– LungsLungs

BirdsBirds– LungsLungs– Anterior and posterior Anterior and posterior

air sacsair sacsFishFish– GillsGills

Aquatic mammalsAquatic mammals– LungsLungs– Special haemoglobin Special haemoglobin

oxygen storage oxygen storage systemssystems

HomeostasisHomeostasis

To stay alive, animals To stay alive, animals need to keep their need to keep their body within certain body within certain limitslimits– TemperatureTemperature– Water balanceWater balance– pHpH– Salt balanceSalt balance

Fedback systems to Fedback systems to help to keep within help to keep within specific limitsspecific limitsOutside limits – deathOutside limits – death– DehydrationDehydration– Heat shockHeat shock– Salt imbalanceSalt imbalance

TemperatureTemperature– InsulationInsulation

– Boundary layerBoundary layer

– Core temepratureCore temeprature

– Surface temepratureSurface temeprature

EarsEars

FingersFingers

ToesToes

Animals have different methods of Animals have different methods of maintaining their body temperaturesmaintaining their body temperatures

Endothermy resulting in homeothermyEndothermy resulting in homeothermy– Use of internal heat sourceUse of internal heat source

Mammals and birdsMammals and birdsDinosaurs?Dinosaurs?

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 invertebratesDinosaurs?Dinosaurs?

HeterothermyHeterothermy– Uses both endothermy and ectothermyUses both endothermy and ectothermy

Bats, bees and hummingbirdsBats, bees and hummingbirdsDinosaurs?Dinosaurs?

Poikilotherms on LandPoikilotherms on Land– 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 varyLizards and snakes have a Lizards and snakes have a 55ooCCAmphibians have a 10Amphibians have a 10ooCCHibernationHibernation

During the day, the During the day, the snake can maintain a snake can maintain a fairly constant fairly constant temperature by adjusting temperature by adjusting it’s environmentit’s environmentDuring the night, it has During the night, it has few optionsfew options– Temperature drops 10-15 Temperature drops 10-15

degreesdegrees– Become torpid (slow Become torpid (slow

moving)moving)– Restricted by environmentRestricted by environment– Maximum size due to Maximum size due to

need for surface area to need for surface area to gather heatgather 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 with Water temperature normally only changes slowly with

seasonseason– Poikilotherms can adjust slowly to a wide range of Poikilotherms can adjust slowly to a wide range of

temperaturestemperatures– Adjust over wider range than land poikilothermsAdjust over wider range than land poikilotherms– Stressed by rapid temperature changesStressed by rapid temperature changes– Smaller change than reptiles over much longer periodSmaller change than reptiles over much longer period

Note that homeotherms are not restricted by their environmentNote that homeotherms are not restricted by their environment– Move at same rate in tropics and at polesMove at same rate in tropics and at poles

Homeothermy needs energyHomeothermy needs energyTherfore homeotherms use Therfore homeotherms use large amounts of glucose large amounts of glucose etc to maintain temperatureetc to maintain temperatureNeed insulation in coldNeed insulation in coldNeed cooling mechanisms Need cooling mechanisms in heatin heatFasterFasterMove for longer periodsMove for longer periodsStrongerStrongerMore environmentsMore environmentsBut limited in sizeBut limited in size– Too big?Too big?

Core temperature build upCore temperature build upDinosaurs?Dinosaurs?

– Too smallToo smallNeed to much energy to Need to much energy to keep temperature stablekeep temperature stable2 gm limit2 gm limitSolexSolex spp eats own body spp eats own body weight in food every day to weight in food every day to maintain temperaturemaintain temperature

Insects can be ectotherm and endothermInsects can be ectotherm and endotherm– Ectotherm for take off (30Ectotherm for take off (30ooC)C)– Endotherm for flight (not more than 44Endotherm for flight (not more than 44ooC)C)

TorporTorpor– Small homeothemic animalsSmall homeothemic animals

Become heterothermicBecome heterothermicBody temperature drops to ambient at nightBody temperature drops to ambient at nightInactiveInactive

– Bats, Some mice, kangaroosBats, Some mice, kangaroos

HibernationHibernation– Many poikilotherms and some mammals have winter torpor to save Many poikilotherms and some mammals have winter torpor to save

energyenergy– Selective advantage when resources are fewSelective advantage when resources are few– MammalsMammals

Heart rate, respiration fallHeart rate, respiration fallTemperature drops to ambientTemperature drops to ambientGroundhogs, chipmonksGroundhogs, chipmonksNot 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!

Homeotherms and some poikilotherms use insulation to minimize temperature Homeotherms and some poikilotherms use insulation to minimize temperature changeschanges– Fur and fat in mammalsFur and fat in mammals– Feathers in birds, note water repellant feathers in water birdsFeathers in birds, note water repellant feathers in water birds– Blubber in aquatic mammals such as sealsBlubber in aquatic mammals such as seals– Water repellant fur in polar bearsWater repellant fur in polar bears– Can also work in hot environment, see camelsCan also work in hot environment, see camels– Shivering in emergencyShivering in emergency– Burn highly vascular brown fat to produce heat, see groundhogs and human babiesBurn highly vascular brown fat to produce heat, see groundhogs and human babies

Terrestrial poikilotherms use microenvironments to change their temperatureTerrestrial poikilotherms use microenvironments to change their temperature– Basking of reptiles followed by cooling in shade can give a fairly stable temperature Basking of reptiles followed by cooling in shade can give a fairly stable temperature

during the dayduring the day– Changing shape to increase or decrease convection and radiationChanging shape to increase or decrease convection and radiation– Note that basking can increase water lossNote that basking can increase water loss

Cooling in birds, mammals and Cooling in birds, mammals and some insects uses evaporationsome insects uses evaporation– Only certain mammals have Only certain mammals have

sweat glandssweat glandsHorses and man. Horses and man. Dogs pantDogs pantPigs wallowPigs wallow

Camels can store body Camels can store body heatheat– 3434ooC in morningC in morning– 4141ooC by late afternoonC by late afternoon

Counter current flow Counter current flow can also be used to can also be used to reduce temperaturereduce temperature– PorpoisePorpoise– GazelleGazelle

Controlling water balanceControlling water balanceAquaticAquatic– FreshwaterFreshwater

Prevent excess uptake of waterPrevent excess uptake of waterRemove excess waterRemove excess water

– Retain salt in special cellsRetain salt in special cells– Large amounts of very dilute urineLarge amounts of very dilute urine

– SaltwaterSaltwaterIf salt concentration very similar to cellsIf salt concentration very similar to cells

– Limited problemsLimited problems

If salt concentration is higherIf salt concentration is higher– Ion pumpsIon pumps– KidneysKidneys– Salt secreting glands in birdsSalt secreting glands in birds

TerrestrialTerrestrial– InputInput

DrinkingDrinkingEatingEatingProduced by metabolismProduced by metabolism

– Output – Need to control in extreme environmentsOutput – Need to control in extreme environmentsUrineUrine

– Concentrated to avoid water lossConcentrated to avoid water loss

FecesFecesEvaporationEvaporation

– 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

Biological Biological clocks have clocks have adaptive valueadaptive value– Used to Used to

change change behaviorbehavior

DailyDailySeasonallySeasonally

Mammals use Mammals use melatonin to melatonin to maintain maintain biological clockbiological clock– Produce by Produce by

pineal gland at pineal gland at nightnight

– Used to get Used to get over jetlagover jetlag

Seasonal Seasonal Changes for Changes for male deermale deerOnly needed Only needed during mating during mating seasonseasonCan be Can be damaged and damaged and need replacingneed replacingMelatonin Melatonin linkedlinked

Seasonal changes for squirrelsSeasonal changes for squirrels

When will you find food at different times of the year?When will you find food at different times of the year?Melatonin linkedMelatonin linkedNote also Seasonal Affected Disorder (SAD) in humansNote also Seasonal Affected Disorder (SAD) in humans– Why you have a very high suicide rate in Norway, Sweden and FinlandWhy you have a very high suicide rate in Norway, Sweden and Finland

Crabs from a tidal estuary Crabs from a tidal estuary retain timed activities in a fixed retain timed activities in a fixed environmentenvironment– Color changeColor change– ActivityActivity– Two clocksTwo clocks

TidalTidal

SolarSolar

Redunancy is probably present in Redunancy is probably present in most organismsmost organisms

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

Buoyancy aidsBuoyancy aids

SharkShark– Large fatty liverLarge fatty liver– 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 air surface with air in lungsin lungs