Population Ecology PDF

POPULATION ECOLOGY  ECOLOGY= INTERACTIONS OF ORGANISMS WITH THEIR PHYSICAL AND BIOLOGICAL ENVIRONMENTS POPULATION ECOLOGY= FLUCTUATIONS IN THE SIZE OF A POPULATION AND THE FACTORS THAT REGULATE THIS BIOSPHERE= PART OF EARTH WHERE LIVING ORGANISMS ARE FOUND ECOSYSTEM= GROUPS OF DIFFERENT...

POPULATION ECOLOGY  ECOLOGY= INTERACTIONS OF ORGANISMS WITH THEIR PHYSICAL AND BIOLOGICAL ENVIRONMENTS POPULATION ECOLOGY= FLUCTUATIONS IN THE SIZE OF A POPULATION AND THE FACTORS THAT REGULATE THIS BIOSPHERE= PART OF EARTH WHERE LIVING ORGANISMS ARE FOUND ECOSYSTEM= GROUPS OF DIFFERENT SPECIES OF ORGANISMS THAT INTERACT WITH EACH OTHER AND THEIR ENVIRONMENT ORGANISM= INDIVIDUAL FORM OF LIFE  COMMUNITY= GROUP OF DIFFERENT SPECIES THAT INTERACT AND INHABIT THE SAME AREA SPECIES= CLOSELY RELATED ORGANISMS THAT ARE VERY SIMILAR TO EACH OTHER AND CAN USUALLY INTERBREED AND PRODUCE FERTILE OFFSPRING INDIVIDUAL= SINGLE ORGANISM POPULATION= ORGANISMS OF THE SAME SPECIES THAT OCCUPY THE SAME AREA AND CAN BREED FREELY DEMOGRAPHICS= STATISTICS- SIZE, AGE DISTRIBUTION, GROWTH RATE, DENSITY, ETC.  WHAT AFFECTS THE SIZE OF A POPULATION? NATALITY- BIRTH RATE IN ANIMALS OR PRODUCTION OF SEEDS IN PLANTS MORTALITY- DEATH RATE IMMIGRATION- INDIVIDUALS MOVE INTO A POPULATION EMIGRATION- INDIVIDUALS LEAVE A POPULATION AND DO NOT RETURN HUMANS: BIRTH RATE IS THE NUMBER OF BIRTHS PER 1000 PEOPLE/YEAR DEATH RATE IS THE NUMBER OF DEATHS PER 1000 PEOPLE/YEAR  IF NATALITY AND IMMIGRATION > MORTALITY AND EMIGRATION= INCREASE IN POPULATION EMIGRATION AND DEATH > NATALITY AND IMMIGRATION = DECREASE IN POPULATION NATALITY AND IMMIGRATION = MORTALITY AND EMIGRATION = STABLE POPULATION CLOSED POPULATION= ONLY NATALITY AND MORTALITY PLAY A ROLE  HOW IS THE GROWTH OF A POPULATION REGULATED? INDIVIDUALS WILL INCREASE EXPONENTIALLY IF THERE ARE NO LIMITED RESOURCES OR PREDATORS AS NUMBERS INCREASE SO DOES ENVIRONMENTAL RESISTANCE THIS CAUSES A DECREASE IN NATALITY & IMMIGRATION AND A INCREASE IN MORTALITY & EMIGRATION THE POPULATION WILL STABILIZE WHEN A BALANCE IS REACHED. CARRYING CAPACITY= THE POPULATION DENSITY THAT THE ENVIRONMENT CAN SUPPORT.  POPULATION FLUCTUATES AROUND THE CARRYING CAPACITY UNTIL THE ENVIRONMENT CHANGES FLUCTUATIONS ARE SEASONAL AND ANNUAL DEPENDING ON AVAILABLE RESOURCES. POPULATION SIZE IS SELF-REGULATING  LIMITING FACTORS FACTORS THAT REGULATE THE GROWTH OF A POPULATION DENSITY INDEPENDENT: NATURAL FACTORS PHYSICAL- RAINFALL, TEMPERATURE, HUMIDITY, ACIDITY, SALINITY CATASTROPHIC- FLOODS, FIRES, VOLCANIC ERUPTIONS, TSUNAMIS, EARTHQUAKES DENSITY DEPENDENT: COMPETITION FOR RESOURCES (FOOD, LIGHT, OXYGEN, WATER, SPACE, ETC.) LARGER NUMBERS ARE MORE EASILY PREYED UPON LARGER NUMBERS ALLOW DISEASES AND PARASITES TO SPREAD MORE EASILY  STABLE POPULATION🡪 NUMBERS DECREASE WHEN ITS SIZE EXCEEDS CARRYING CAPACITY AND INCREASE AGAIN WHEN NUMBERS FALL BELOW CARRYING CAPACITY. UNSTABLE POPULATION🡪 OCCURS IF POPULATION FAR EXCEEDS CARRYING CAPACITY HABITAT DETERIORATES RAPIDLY AND LOWERS THE CARRYING CAPACITY EVENTUALLY IT CAN’T SUPPORT THE POPULATION, WHICH WILL RAPIDLY DECREASE AND POSSIBLY BECOME EXTINCT  ESTIMATING POPULATION SIZE IMPORTANT TO MEASURE TO SEE IF A POPULATION SIZE IS CHANGING OVER TIME. 1. DIRECT METHOD 2. INDIRECT METHOD  1. DIRECT METHODS INVOLVE COUNTING EVERY SINGLE INDIVIDUAL IN THE POPULATION= CENSUS CAN BE USED: ORGANISMS ARE LARGE ENOUGH TO BE SEEN AREA OF POPULATION IS NOT TOO LARGE DIRECT METHODS CAN BE USED FOR INDIVIDUALS: SLOW MOVING E.G. SNAILS STATIONARY E.G. PLANTS USUALLY STAY IN FIXED POSITIONS E.G. MUSSELS  IF THE AREA IS TOO LARGE TO COUNT EVERY INDIVIDUAL: AERIAL PHOTOGRAPHS CAN BE TAKEN E.G. PENGUINS HELICOPTERS CAN BE USED TO COUNT LARGER INDIVIDUALS E.G. ELEPHANT HUMANS: CENSUS FORMS CAN BE FILLED IN ACCOUNTING FOR EVERYONE IN A HOUSEHOLD  2. INDIRECT METHODS COUNTING A SAMPLE NUMBER OF THE POPULATION AND THEN ESTIMATING THE TOTAL SIZE QUADRAT METHOD: COUNTING THE NUMBER OF INDIVIDUALS IN SMALL, MEASURED AREAS (QUADRATS) CALCULATE THE POPULATION SIZE WITH THE FOLLOWING FORMULA: N = (NUMBERS IN SAMPLE X SIZE OF WHOLE HABITAT) / SIZE OF QUADRAT N= TOTAL POPULATION QUADRAT METHOD IS USED TO ENABLE COMPARABLE SAMPLES TO BE OBTAINED  METHOD: MEASURE THE TOTAL AREA SIZE USE A WOODEN FRAME OF KNOWN DIAMETER (USUALLY 0.5 OR 1 M2) AS A QUADRAT THE SAME QUADRAT SIZE MUST BE USED FOR EACH SAMPLE QUADRAT SHOULD BE DISTRIBUTED AT RANDOM COUNT THE INDIVIDUALS IN EACH QUADRAT TAKE SEVERAL SAMPLES AND CALCULATE THE NUMBER OF INDIVIDUALS PER QUADRAT CALCULATE THE SIZE OF THE POPULATION USING THE FORMULA.  IMPORTANCE OF RANDOM SAMPLING: DISTRIBUTION OF INDIVIDUALS IS NOT NECESSARILY UNIFORM THROUGHOUT AN AREA RANDOM SAMPLING IS DONE TO ACHIEVE A TRUE REFLECTION OF THE DISTRIBUTION  MARK-RECAPTURE METHOD: KNOWN NUMBER OF INDIVIDUALS ARE CAUGHT, MARKED AND THEN RELEASED AFTER A SUITABLE PERIOD OF TIME ANOTHER SAMPLE IS CAPTURED AND THE MARKED INDIVIDUALS ARE COUNTED. SUITABLE FOR ANIMALS THAT ARE: MOBILE E.G. BIRDS NOT EASILY VISIBLE E.G. FISH  METHOD: MARK OUT A WELL-DEFINED AREA CAPTURE AS MANY INDIVIDUALS AS POSSIBLE AND MARK THEM RELEASE MARKED INDIVIDUALS BACK INTO THE ENVIRONMENT AND ALLOW THEM TIME TO MIX THOROUGHLY WITH UNMARKED INDIVIDUALS RECAPTURE AS MANY INDIVIDUALS AS POSSIBLE COUNT THE TOTAL NUMBER OF MARKED INDIVIDUALS IN THE SECOND CAPTURE CALCULATE THE TOTAL POPULATION SIZE USING THE PETERSEN INDEX: P = (M X C) / R P🡪 ESTIMATED POPULATION M🡪 TOTAL NUMBER OF MARKED ANIMALS C🡪 TOTAL NUMBER OF ANIMALS CAUGHT IN SECOND SAMPLE R🡪 TOTAL NUMBER OF MARKED ANIMALS IN SECOND SAMPLE  PRECAUTIONS: ONLY A SHORT TIME PERIOD SHOULD PASS BETWEEN SAMPLINGS SO THAT NO BIRTHS AND DEATHS OCCUR SAMPLING SHOULD BE REPEATED SEVERAL TIMES AND AN AVERAGE POPULATION CALCULATED THE MARKING MUST NOT DAMAGE THE INDIVIDUAL OR AFFECT ITS MOVEMENT OR BEHAVIOUR MARKED ANIMAL/S MUST MIX FREELY WITH THE REST OF THE POPULATION BEFORE A NEW SAMPLE IS TAKEN NO IMMIGRATION OR EMIGRATION IS ALLOWED🡪 POPULATION MUST BE CLOSED PREDATOR-PREY RELATIONSHIPS  ORGANISMS IN AN ECOSYSTEM ARE INTERDEPENDENT CHANGES IN POPULATION SIZE OF ONE SPECIES CAN DRASTICALLY AFFECT THAT OF ANOTHER PREDATION= THE PREDATOR KILLS AND EATS ANOTHER SPECIES, THE PREY PREDATOR AND PREY EVOLVE TOGETHER AND ARE PART OF THE SAME ENVIRONMENT PREDATORS HELP CREATE AND MAINTAIN GREATER DIVERSITY WITHIN AN ECOSYSTEM: REGULATE THE ABUNDANCE AND DISTRIBUTION OF PREY SPECIES INCREASE BIODIVERSITY OF COMMUNITIES BY PREVENTING A SINGLE SPECIES FROM BECOMING DOMINANT KEEP PREY POPULATION GENETICALLY FIT (REMOVE WEAK AND INJURED) PROVIDE VITAL FOOD SOURCES FOR SCAVENGERS  RELATIONSHIP: AS PREY POPULATION DECREASES DUE TO PREDATOR KILLING THE FOOD FOR PREDATORS DECREASES AND THEIR NUMBERS DECLINE PREDATOR PRESSURE DECREASES AND PREY NUMBERS INCREASE AGAIN THE RESULT IS CYCLICAL RISING AND FALLING OF THE NUMBERS OF THE PREY POPULATION WITH A SLIGHTLY LATER CYCLICAL PATTERN OF THE PREDATOR FLUCTUATIONS MAY BE SEASONAL OR OVER A FEW YEARS E.G: 1. APHID-LADYBIRD 2. LION-ZEBRA 3. SHARK-FISH 1. APHID-LADYBIRD LADYBIRDS FEED ON APHIDS (INSECTS) 2. LION-ZEBRA LIONS FEED ON ZEBRA BOTH HAVE ADAPTED IN SPEED AND MOVEMENT FASTER LIONS ARE ABLE TO CATCH AND EAT THEIR PREY MORE EASILY THAN SLOWER LIONS FASTER ZEBRA ARE ABLE TO ESCAPE LIONS BOTH THESE STRONGER INDIVIDUALS SURVIVE AND REPRODUCE= CO-EVOLUTION 3. SHARK-FISH SHARK KEEP POPULATIONS OF OTHER FISH AND MARINE ORGANISMS HEALTHY AND IN BALANCE GO AFTER OLD, SICK AND SLOW FISH THIS PREVENTS THE SPREAD OF DISEASE AND STRENGTHENS THE PREY GENE POOL THIS RESULTS IN LARGER NUMBERS OF HEALTHIER FISH SHARKS PREVENT FISH FROM INCREASING TOO RAPIDLY AND BECOMING TOO DOMINANT  FOOD WEBS IMPACT ON POPULATIONS FOOD WEB= INTERCONNECTED SET OF FOOD CHAINS IN AN ECOSYSTEM THE REMOVAL OF ONE SPECIES MAY HAVE A LARGE IMPACT ON THE POPULATIONS OF MANY OTHER SPECIES IF TOP PREDATORS (LION, SHARK) ARE REMOVED THE DISRUPTION IS EVEN WORSE  3. COMPETITION WHEN TWO OR MORE INDIVIDUALS COMPETE FOR THE SAME RESOURCES THAT ARE IN SHORT SUPPLY A. INTRASPECIFIC COMPETITION: BETWEEN INDIVIDUALS OF THE SAME SPECIES COMPETE FOR REPRODUCTIVE MATES AS WELL AS RESOURCES MOST INTENSE AS INDIVIDUALS HAVE SIMILAR HABITATS AND RESOURCE REQUIREMENTS B. INTERSPECIFIC COMPETITION: BETWEEN INDIVIDUALS OF DIFFERENT SPECIES NICHES IN A HABITAT ARE VERY SIMILAR ECOLOGICAL NICHES: ALL THE CONDITIONS NECESSARY FOR AN ORGANISM TO SURVIVE AND REPRODUCE INDIVIDUALS OF A POPULATION MUST SURVIVE AND REPRODUCE THEY MUST: TOLERATE THE PHYSICAL ENVIRONMENT (TEMPERATURE, PH) OBTAIN ENERGY AND NUTRIENTS COPE WITH COMPETITION AVOID PREDATORS  SPECIALISATION= THE STRUCTURAL AND BEHAVIOURAL ADAPTATION THAT ENABLE INDIVIDUALS OF DIFFERENT SPECIES TO CO-EXIST. OCCURS WHEN TWO SPECIES WITH SIMILAR ECOLOGICAL NICHES OCCUPY THE SAME HABITAT. E.G GALAPAGOS FINCHES: EVOLVED A LARGE VARIETY OF BEAK SHAPES AND SIZES TO SUIT THEIR FOOD CREATE THEIR OWN ECOLOGICAL NICHES TO PREVENT COMPETITION COMPETITION THAT ARISES FROM SPECIALIZATION CAN LEAD TO COMPETITIVE EXCLUSION OR COMPETITIVE COEXISTENCE  COMPETITIVE EXCLUSION WHEN ONE OF THE TWO COMPETING SPECIES IS MUCH MORE SUCCESSFUL THAN THE OTHER SUCCESSFUL SPECIES SURVIVES AND THE OTHER DISAPPEARS CAN RESULT IN EXTINCTION AND IS IMPORTANT IN EVOLUTION E.G. MONKEYS OUT-COMPETED LEMURS IN AFRICA  COMPETITIVE CO-EXISTENCE ARISES WHEN TWO COMPETING SPECIES CO-EXIST IN THE SAME HABITAT USE THE RESOURCES AVAILABLE DIFFERENTLY= RESOURCE PARTITIONING RESOURCE PARTITIONING: EVOLUTIONARY PROCESS WHEREBY SPECIES WITH SIMILAR REQUIREMENTS LIVING IN THE SAME HABITAT, EVOLVE SPECIALISED TRAITS THAT ENABLE THEM TO UTILIZE THE RESOURCES DIFFERENTLY, CREATING SEPARATE NICHES TO REDUCE INTERSPECIFIC COMPETITION AND MAKE CO-EXISTENCE POSSIBLE. HOW CAN RESOURCES BE PARTITIONED? TWO SPECIES CAN ELIMINATE COMPETITION FOR THE SAME RESOURCE BY USING THE RESOURCE: AT DIFFERENT TIMES (FEEDING DURING DAY OR NIGHT) IN DIFFERENT PARTS OF THE HABITAT (FEEDING AT DIFFERENT DEPTHS IN A LAKE) IN DIFFERENT PARTS OF THE SAME PLANT (GIRAFFE AND KUDU)  A. STRATEGY AMONG PLANTS FOREST: CREATE A VERTICAL STRUCTURE TO DIVIDE VEGETATION INTO LAYERS= STRATIFICATION MADE UP OF: TALL TREES- CREATE A HIGH UPPER CANOPY AND ARE EXPOSED TO MAXIMUM LIGHT INTENSITY. E.G. YELLOW WOODS SHORTER TREES- CREATE THE UNDERSTORY OF A FOREST AND ARE EXPOSED TO LESS LIGHT INTENSITY. E.G. BLADDERNUTS PIONEER SPECIES AND YOUNG TREES- GROW IN THE GAPS. E.G. WILD PEACH EPIPHYTES THAT GROW ON TREE TRUNKS AND CLIMBERS THAT TWINE AROUND BRANCHES E.G. LICHENS AND CAT-THORN HERBACEOUS GROUND LAYER- VARIOUS FERNS AND SHADE-LOVING PLANTS. E.G. GRASS Different layers of vegetation are adapted to photosynthesise in different light intensities.  B. STRATEGIES AMONG ANIMALS 1. COEXISTING LARGE HERBIVORES IN AFRICAN SAVANNAH: GIRAFFE AND KUDU ARE BROWSERS GIRAFFE ARE ADAPTED TO FEED OFF THE HIGHER BRANCHES OF TREES KUDU BROWSE ON THE LOWER BRANCHES COMPETITION IS ELIMINATED 2. COEXISTING SHOREBIRDS: FEEDING HABITS DIVIDE TERRITORY HORIZONTALLY AND VERTICALLY HORIZONTAL= SPECIES CAN FEED ABOVE THE TIDE LINE, FOLLOW THE WATERLINE, IN THE SHALLOWS, ROCKY AREAS, DEEPER WATER VERTICAL= PICK TITBITS OFF THE GROUND/WATER SURFACE, PROBE UNDERGROUND, PREY ON CREATURES IN DEEPER WATERS PICKERS= SEARCH FOR FOOD USING SIGHT AND “RUN AND PECK” e.g. PLOVERS PROBERS= LONG BILLS THAT STICK INTO SAND/MUD TO FEEL FOR PREY e.g. SANDPIPERS  MORPHOLOGY: DIFFERENT LENGTH BILLS AND LEGS= FEED ON DIFFERENT TYPES OF FOOD OYSTERCATCHERS= TRIANGULAR BILL TO STAB OR SEVER THE MUSCLES THAT CLOSE SHELLS OR SMASH OPEN THE SHELL UPTURNED BILLS= SCYTHE WATER TO STIR UP AND SNAG PREY WADERS= LONG, SLENDER LEGS TO WADE INTO THE WATER AND FEED ON MOLLUSCS, CRUSTACEANS AND SMALL FISH  3. COEXISTING PREDATORS LEOPARDS AND LION HUNT AT DIFFERENT TIMES OF THE DAY HUNT DIFFERENT TYPES OF PREY (LIONS- MEDIUM PREY, LEOPARD- SMALLER PREY) = DIETARY NICHE SEPARATION HUNT IN DIFFERENT AREAS OF THE HABITAT  4. ECOLOGICAL SUCCESSION PREDICTABLE PATTERN OF GRADUAL CHANGE OVER TIME IN THE TYPES OF SPECIES IN A COMMUNITY FOLLOWING A DISTURBANCE. REFERS TO THE SEQUENCE OF COMMUNITIES, WHERE ONE REPLACES ANOTHER OVER TIME= LONG-TERM CHANGES IN THE ECOSYSTEM. TWO TYPES: PRIMARY SUCCESSION: ON SITES THAT HAVE NOT PREVIOUSLY HAD PLANTS GROWING ON THEM. E.G. BEACHES, SEVERE LANDSLIPS, PONDS, BARE ROCK SECONDARY SUCCESSION: IN AREAS WHERE A DISTURBANCE REMOVES SOME OR ALL SPECIES BUT THE SOIL REMAINS  STAGES IN SUCCESSION NOT RANDOM THREE STAGES: 1. PIONEER SPECIES STAGE: BARE GROUND CONDITIONS FAVOUR PIONEER SPECIES GROW BEST WITH LITTLE COMPETITION ARE HARDY (WITHSTAND EXTREME CONDITIONS) ESTABLISH RAPIDLY SPORES OR SEEDS THAT DISPERSE OVER LONG DISTANCES DO NOT GROW IN SHADE PREPARE THE SURROUNDINGS FOR LATER COLONISTS: BUILD-UP, STABILIZE AND ENRICH SOIL ALTER LIGHT AVAILABILITY BY PROVIDING SHADE OTHER SPECIES WILL REPLACE THE PIONEER SPECIES 2. INTERMEDIATE SPECIES STAGE: ECOLOGICAL CONDITIONS CHANGE AND A GREATER VARIETY AND NUMBER OF ORGANISMS CAN MOVE IN AS SOIL BUILDS UP SMALL, NON-WOODY HERBACEOUS PLANTS GIVE WAY TO BIGGER WOODY PLANTS WHICH GIVE WAY TO HARDY, WOODY PLANTS WHICH GIVE WAY TO BUSHES AND SHRUBS LARGER HERBIVORES AND SMALL CARNIVORES, SNAKES AND RAPTORS BECOME PART OF THE COMMUNITY MAKE COMMUNITIES MORE STRUCTURALLY COMPLEX 3. CLIMAX COMMUNITY SEMI-STABLE STAGE/ ENDPOINT OF SUCCESSION VARY IS SIZE AND TYPE ANIMAL SPECIES ARE DIVERSE- LARGE HERBIVORES AND CARNIVORES Stage Primary Succession Secondary succession Pioneer species - bare ground - after a disturbance - hardy species - soil is present - establish rapidly - annuals (herbs and weeds) - have spores for dispersal over long distances - later grasses and perennials - don’t grow in shade - climbers follow - usually lichens (don’t need soil) - followed by mosses - then ferns, grasses and annuals - climbers follow - mites, ants and spiders - small insects, rodents and birds - earthworms- decomposers Intermediate - soil can hold more water and is more fertile - soil can hold more water and is more fertile species - shade available - shade available - temperatures are less extreme - temperatures are less extreme - small shrubs plants to larger woody plants - small non-woody herbaceous species appear - followed by larger woody trees - larger herbivores and small carnivores - snakes and raptors Climax - endpoint community - semi-stable - large trees (forest) ; grasses (savannah) - diverse animal life- large herbivores and carnivores  FACTORS THAT DETERMINE AN ENDPOINT TO A COMMUNITY ANY COMMUNITY CAN CHANGE- CAUSED BY ENVIRONMENTAL FLUCTUATIONS: 1. RAINFALL (DETERMINE IF THE ENDPOINT IS A FOREST OR GRASSLAND) 2. OVERGRAZING (UNPALATABLE SPECIES BECOME DOMINANT) 3. DRAINING OF WETLANDS (DRAINAGE CAUSES THE DISAPPEARANCE OF WETLAND CLIMAX SPECIES SUCH AS FROGS AND REEDS) 4. CLIMATE CHANGE (GRASSLANDS THAT BECOME WETTER FORM FORESTS) 5. INVASION BY ALIENS (BECOME THE DOMINANT SPECIES)  5. SOCIAL ORGANISATION STRUCTURE OF RELATIONSHIPS WITHIN A GROUP FEATURES NEED TO BE DIVIDED AMONG THE GROUP: - RESOURCES🡪 GOOD, TERRITORIES, NEST SITES - ACTIVITIES 🡪 PROTECTION AND OTHER SKILLS INSECTS (BEES & TERMITES) AND MAMMALS (WILD DOG) IMPROVES THE SURVIVAL AND REPRODUCTIVE SUCCESS OF AN INDIVIDUAL  SOCIAL ORGANIZATION MAKES IT EASIER TO: AVOID BEING ATTACKED BY PREDATORS FIND FOOD BY HUNTING COLLECTIVELY DIVIDE LABOUR AMONG INDIVIDUALS FIND MATES PROTECT RESOURCES REGULATE POPULATION SIZE  1. HERDS OR FLOCKS AS A PREDATOR AVOIDANCE STRATEGY THE SAFETY OF THE GROUP IS INCREASED BY AVOIDING AND DEFENDING AGAINST PREDATORS ALTHOUGH LARGE GROUPS ARE MORE EASILY SEEN LESS PREY ARE CAPTURED BECAUSE: THERE ARE MORE EYES AND EARS AND THE GROUP ARE MORE WATCHFUL LARGE HERDS/FLOCKS CAN MOB (SURROUND AND OVERPOWER) A PREDATOR DILUTION EFFECT= THE GREATER THE NUMBER OF INDIVIDUALS, THE LARGER THE SURVIVAL CHANCE CONFUSION AND DISTRACTION EFFECT= HERD SCATTERS IN ALL DIRECTIONS AND CONFUSES THE PREDATOR MOULTING AND VULNERABLE ARE PROTECTED BY OTHER MEMBERS INEXPERIENCED ARE GIVEN GUIDANCE AND PROTECTION DURING MIGRATION  2. PACKS AS A SUCCESSFUL HUNTING STRATEGY AFRICAN WILD DOGS: ONE OF THE HIGHEST SUCCESS RATES OF ANY PREDATOR SPECIES IN AFRICA (8/10) AFTER PREY DETECTION THEY CHASE IT AT A FAST RUN (45KM/H)- THEY ARE TIRELESS RUNNERS WHEN THE PREY TIRES ONE DOG GRABS ITS TAIL AND THE OTHER ITS UPPER LIP THE REST KILL THE PREY QUICKLY AND EFFICIENTLY YOUNG FEED FIRST DOGS LEFT BEHIND IN THE DEN (DOMINANT FEMALE AND PUPS, INJURED OR SICK) ARE FED ON REGURGITATED MEAT NEEDS OF THE WHOLE PACK ARE SATISFIED  3. ANIMALS WITH A DOMINANT BREEDING PAIR E.G. WILD DOGS STRICT RANKING SYSTEM LED BY THE ALPHA MALE AND FEMALE (MATE FOR LIFE AND PREVENT OTHER FEMALES FROM BREEDING) FEMALE OFFSPRING REACH SEXUAL MATURITY AT 18 MONTHS-2 YEARS AND THEY LEAVE TO JOIN A NEW PACK MALES REMAIN WITH THEIR PACK FOR THE REST OF THEIR LIVES (+/- 11 YEARS)  DOMINANT PAIR KEEPS THE PACK UNDER CONTROL TO ENSURE THE SURVIVAL OF THE SPECIES RAISING PUPS AND CARING FOR THE OLD AND SICK IS A GROUP TASK SUBORDINATE MEMBERS BENEFIT BY HAVING ACCESS TO MATES AND OTHER RESOURCES THESE MEMBERS MAY BECOME DOMINANT AT LATER STAGES OF THEIR LIVES  4. DIVISION OF TASKS AMONG CASTES MOST SOCIAL GROUPS HAVE DIVISION OF TASKS OR LABOUR EACH INDIVIDUAL HAS AN IMPORTANT ROLE TO PLAY EUSOCIAL ANIMALS ARE THE MOST ADVANCED FORM OF SOCIAL ORGANIZATION AND LIVE IN COLONIES: DOMINANT BREEDING PAIR OR SINGLE FEMALE QUEEN NON-BREEDING ANIMALS HAVE DIFFERENT TASKS TO PERFORM BEE, WASPS, TERMITES, ANTS AND NAKED MOLE-RATS ARE ALL EUSOCIAL TERMITES: LIVE IN COLONIES CREATE TERMETARIA (MOUNDS OF SOIL CEMENTED WITH FAECES AND SALIVA) CASTE SYSTEM: 1. REPRODUCTIVES: ALATES- WINGED TERMITES THAT FOUND THE COLONY. APPEAR IN RAINY SEASONS AND MATE QUEEN AND KING- AFTER LOSING THEIR WINGS THEY BURROW UNDERGROUND AND BECOME QUEEN AND KING. THE QUEEN LAYS EGGS (THOUSANDS/WEEK) THAT HATCH INTO NYMPHS, WHICH WILL GROW INTO CASTES WITH DIFFERENT ROLES IN THE COLONY. KING CONTINUALLY MATES WITH THE QUEEN. YOUNG REPRODUCTIVE- EITHER BECOME NEW ALATES OR SUPPLEMENTARY REPRODUCTIVES 2. WORKERS: MAJORITY OF TERMITES (MALE OR FEMALE) MAKE TUNNELS, BUILD THE TERMITE MOUND, FORAGE FOR FOOD, LOOK AFTER EGGS, FEED OTHER MEMBERS DIGEST CELLULOSE IN LEAVES AND WOOD BY BACTERIA AND PROTOZOA IN THEIR STOMACHS, WHICH THEY PASS TO THE KING AND QUEEN, NYMPHS AND SOLDIERS 3. SOLDIERS: 5% OF THE COLONY HUGE BITING OR SQUIRTING MOUTHPARTS FOR DEFENSE  ALL NYMPHS ARE GENETICALLY IDENTICAL AND CAN DEVELOP INTO ANY CASTE REPRODUCTIVES AND SOLDIER CASTES SECRETE A PHEROMONE TO INHIBIT DEVELOPMENT OF REPRODUCTIVE OR SOLDIERS  6. HUMAN POPULATION DYNAMICS 10 000 YEARS AGO THERE WERE NO MORE THAN 10 MILLION PEOPLE ON EARTH DEATH RATES WERE HIGH BECAUSE OF STARVATION, DISEASE AND HIGH INFANT MORTALITY RATES IN THE LAST 1000 YEARS POPULATION GROWTH HAS INCREASED EXPONENTIALLY  CURRENT HUMAN POPULATION: JULY 2015= JUST OVER 7.3 BILLION INCREASED BY APPROXIMATELY 216 000 PEOPLE/DAY = ANNUAL INCREASE OF 83 MILLION MOST OF THE GROWTH IS IN DEVELOPING COUNTRIES  DUE TO: REDUCED ENVIRONMENTAL RESISTANCE AND INCREASING THE CARRYING CAPACITY OF THE WORLD’S FOOD PRODUCING REGIONS 1. FOOD PRODUCTION HAS INCREASED SUBSTANTIALLY: a. more land cultivation b. food production methods improved 2. METHODS OF TREATING DISEASES HAVE IMPROVED GREATLY: a. more people stay alive to reproduce ENVIRONMENTAL RESISTANCE IS THE RESISTANCE PRESENTED BY THE ENVIRONMENTAL CONDITIONS TO LIMIT A SPECIES FROM GROWING OUT OF CONTROL OR TO STOP THEM FROM REPRODUCING AT A MAXIMUM RATE. INCLUDES ABIOTIC AND BIOTIC FACTORS.  DO COUNTRIES OF THE WORLD DIFFER? MORE DEVELOPED COUNTRIES (MDCs) SLOW POPULATION GROWTH (0.1%/YEAR) HIGH STANDARD OF LIVING (JAPAN, AUSTRALIA) LESS DEVELOPED COUNTRIES (LDCs) RAPID POPULATION GROWTH (1.6%/YEAR) LOWER STANDARD OF LIVING (ASIA, AFRICA)  FUTURE? NEXT 150 YEARS THE GROWTH WILL BE MORE LOGISTIC AND LESS EXPONENTIAL MDCs HAVE ALREADY SHIFTED TO A STABLE POPULATION AS NATALITY HAS DECREASED: LATE MARRIAGES BIRTH CONTROL more individuals are educated and therefore SEXUAL ABSTINENCE responsible. LDC POPULATIONS WILL CONTINUE TO INCREASE DUE TO IMPROVED MEDICAL TREATMENTS  ECOLOGICAL FOOTPRINT OF MDCs AND LDCs GROWTH IS PLACING EXTREME PRESSURE ON THE EARTH’S RESOURCES AND ENVIRONMENT: PRIMARILY DUE TO MDCs MDCs ARE RESPONSIBLE FOR MORE TOTAL POLLUTION AND MORE TOTAL CONSUMPTION THAN LDCs MDCs ACCOUNT FOR 22% OF THE WORLD’S POPULATION YET THEY PRODUCE 90% OF HAZARDOUS WASTE AND USE MORE RESOURCES https://www.youtube.com/watch?v=E8dkWQVFAoA  POPULATION PYRAMID AGE-SEX PYRAMID BAR GRAPH THAT SHOWS THE COMPOSITION BY AGE AND SEX OF A NATION’S POPULATION A POPULATION CONTAINS 3 MAJOR AGE/SEX GROUPS: PRE-REPRODUCTIVE REPRODUCTIVE POST-REPRODUCTIVE AGE STRUCTURE= RELATIVE NUMBERS OF INDIVIDUALS OF EACH AGE IN A POPULATION  TWO BACK-TO-BACK BAR GRAPHS WITH THE POPULATION NUMBERS PLOTTED ON THE HORIZONTAL AXIS AND AGE ON THE VERTICAL AXIS TOP OF THE PYRAMID= OLDER POPULATION BOTTOM=YOUNGER POPULATION MALES= SHOWN ON THE LEFT (PERCENTAGE OR ACTUAL NUMBERS) FEMALES=SHOWN ON RIGHT (FIVE YEAR AGE GROUPS)  1. RAPIDLY GROWING POPULATION HIGH BIRTH RATE RAPID FALL IN EACH UPWARD AGE GROUP DUE TO HIGH DEATH RATES AND SHORT LIFE EXPECTANCY (LDCs- AFRICA, ASIA & SOUTH AMERICA) HIGH DEPENDENCY RATIO  2. STABLE POPULATION DECLINING BIRTH RATE LOW DEATH RATE MORE PEOPLE LIVING TO AN OLD AGE (MDCs- CANADA & AUSTRALIA)  3. DECLINING POPULATION LOW BIRTH RATE LOW DEATH RATE HIGHER DEPENDENCY RATIO LONGER LIFE EXPECTANCY (AFFLUENT COUNTRIES- SWEDEN, NORWAY)  PRE-REPRODUCTIVE AGE LARGEST= POPULATION WILL INCREASE IF IT IS THE SMALLEST= POPULATION WILL DECREASE A POPULATION WITH MORE OLD, NON-PRODUCTIVE INDIVIDUALS WILL GROW MORE SLOWLY THAN A POPULATION WITH MORE YOUNG INDIVIDUALS PURPOSE: QUICK ASSESS OF A NATION’S GROWTH TO SHOW IF A COUNTRY IS MORE OR LESS DEVELOPED TOTAL NUMBER OF PEOPLE IN EACH AGE RANGE HISTORY OF A NATION’S GROWTH DETERMINE THE NUMBER OF ECONOMIC DEPENDENTS 0-15 YEARS AND 65+ YEARS= ECONOMICALLY DEPENDENT 15-65= PRODUCTIVE, WORKING GROUP (LABOUR FORCE)  WHAT CAN CAUSE THE MAKEUP OF A POPULATION TO CHANGE? HIV/AIDS- DEATH OF SEXUALLY ACTIVE INDIVIDUALS (MAIN FACTOR) YOUNG IMMIGRANTS BEING ABSORBED AND INDIVIDUALS LOST TO EMIGRATION MEN FIGHTING WARS REDUCED BIRTHS DUE TO ECONOMIC CRISIS SA: IN 1960 THE POPULATION WAS 17.4 MILLION. IN 2014= 54 MILLION (190% INCREASE)  WILL THE ENVIRONMENT SURVIVE THE HUMAN EXPLOSION? ECOLOGICAL FOOTPRINT= HUMAN DEMAND ON THE EARTH’S ECOSYSTEM (AMOUNT OF BIOLOGICALLY PRODUCTIVE LAND AND SEA AREA NECESSARY TO SUPPLY THE RESOURCES A HUMAN POPULATION CONSUMES) FOOTPRINT ACCOUNTS FOR ALL DEMANDS ON THE BIOSPHERE: AT PRESENT THE ECOLOGICAL FOOTPRINT IS 2.7 GLOBAL HECTARES/PERSON WORLD BIOCAPACITY IS 2.1 GLOBAL HECTARES/PERSON (DEFICIT OF 0.6) IF ECOLOGICAL FOOTPRINTS CONTINUE TO INCREASE OUR PLANET EARTH WILL BE PERMANENTLY DAMAGED READ THROUGH HUMAN NEED FOR LAND VS CONSERVATION (PG 34-35)