B2

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B2A - Classification

CLASSIFICATION - ORGANISING LIVING ORGANISMS INTO GROUPS

  • NATURAL CLASSIFICATION SYSTEMS - BASED ON EVOLUTIONARY RELATIONSHIPS AND GENETIC SIMILARITIES BETWEEN ORGANISMS
  • ARTIFICIAL CLASSIFICATION - BASED ON APPEARANCE RATHER THAN GENES - USED TO IDENTIFY ORGANISMS

DIVIDING LIVING THINGS

  • DIVIDED INTO KINGDOMS AND THEN SUB DIVIDED INTO SMALLER AND SMALLER THINGS
  • ORDER - KINDOM --> PHYLUM --> CLASS --> ORDER --> FAMILY --> GENUS --> SPECIES
  • GENUS - GROUP OF CLOSELY RELATED SPECIES

DIFFICULTIES IN CLASSIFICATION

  • MANY ORGANISMS SHARE CHARACTERISTICS - DIFFICULT TO MAKE DISTINCT GROUPS
  • NEWLY DISCOVERED SPECIES MAY NOT FIT INTO ANY CATAGORY - LIVING SPECIES OR NEWLY DISCOVERED FOSSILS - MAY HAVE FEATURES OF TWO DIFFERENT CLASSES
  • DNA SEQUENCING ALLOWS US TO SEE GENETIC DIFFERENCES BETWEEN GROUPS - AS DATA COLLECTED, WE MAY FIND THAT SOME GROUPS ARE NOT AS CLOSELY RELATED AS WE THINK
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B2A - Classification

EVOLUTIONARY TREES - SHOW HOW CLOSELY RELATED DIFFERENT SPECIES ARE TO EACHOTHER

  • SHOW COMMON ANCESTORS AND RELATIONSHIPS BETWEEN SPECIES - THE MORE RECENT THE COMMON ANCESTOR, THE MORE CLOSELY RELATED THE TWO SPECIES ARE AND THE MORE CHARACTERISTICS THEY'RE LIKELY TO SHARE
  • SCIENTISTS STUDY LOTS OF CHARACTERISTICS FOR A LARGE GROUP OF ORGANISMS TO FIND OUT EVOLUTIONARY RELATIONSHIPS - ONLY POSSIBLE THANKS TO ADVANCES IN ICT
  • SPECIES - A GROUP OF ORGANISMS WHICH CAN INTERBREED TO PRODUCE FERTILE OFFSPRING

PROBLEMS WITH CLASSIFYING ORGANISMS INTO SPECIES

  • ASEXUAL REPRODUCTION - E.G. BACTERIA - DON'T INTERBREED WITH OTHER ORGANISMS - DON'T FIT DEFINITION
  • HYBRIDS - USUALLY INFERTILE - AREN'T A NEW SPECIES
  • EVOLUTION - ORGANISMS CHANGE AND EVOLVE OVER TIME - WAY THEY'VE BEEN CLASSIFIED MAY HAVE TO CHANGE - SOMETIMES ORGANISMS WILL CHANGE SO MUCH THEY HAVE TO FORM A NEW SPECIES
  • RECENT COMMON ANCESTORS - MAY LOOK AND LIVE DIFFERENTLY - NEED TO CONSIDER BOTH EVOLUTIONARY AND ENVIRONMENTAL RELATIONSHIPS IN ORDER TO CLASSIFY ORGANISMS
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B2A - Classification

THE BINOMIAL SYSTEM 

EVERY SPECIES HAS A TWO PART LATIN NAME - FIRST PART REFERS TO GENUS, SECOND TO SPECIES - ALLOWS SCIENTISTS WHO SPEAK DIFFERENT LANGUAGES TO REFER TO SPECIES BY THE SAME NAME - AVOIDS POTENTIAL CONFUSION

CLASSIFYING ARTHROPODS

INSECTS - 6 LEGS       ARACHNIDS - 8 LEGS       CRUSTACEANS - 10 - 14 LEGS      MYRIAPODS - MORE THAN 20 LEG

 

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B2B - Energy Flow

PYRAMIDS OF BIOMAS

EACH BAR ON PYRAMID SHOWS MASS OF LIVING MATERIAL AT THAT STAGE OF THE FOOD CHAIN - HOW MUCH ALL OF THE LEVELS OF ORGANISMS WOULD WEIGH IF YOU PUT THEM TOGETHER

  •  E.G. 5000 KG OF PLANTS FEEDS 500 KG OF MICE WHICH    FEED  50 KG OF SNAKES AND SO ON
  •  ALWAYS PYRAMID SHAPED - BIOMAS LOST ON EACH STAGE OF THE  FOOD  CHAIN
  •  DRY MASS IS USED TO CONSTRUCT PYRAMIDS OF BIOMAS - CAN BE  DIFFICULT TO WEIGH BECAUSE ORGANISMS NEED TO BE KILLED FIRST
  •  SOMETIMES DIFFICULT TO CONSTRUCT ACCURATE PYRAMID OF  BIOMAS -  SOME ORGANISMS FEED AT MORE THAN ONE TROPHIC LEVEL

PYRAMIDS OF NUMBERS

  • EACH BAR ON PYRAMID SHOWS NUMBER OF ORGANISMS AT EACH STAGE OF FOOD CHAIN - NOT MASS
  • NOT ALWAYS PYRAMID SHAPED (E.G. ONE PEAR TREE WOULD FEED A HUGE NUMBER OF APHIDS SO THE BOTTOM BAR (PEAR TREES) WOULD BE MUCH SMALLER THAN THE SECOND BAR (APHIDS)
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B2B - Energy Flow

ENERGY TRANSFER

  • ENERGY FROM SUN - SOURCE OF ENERGY FOR NEARLY ALL LIFE ON EARTH - PLANTS USE SOME OF IT FOR PHOTOSYNTHESIS - GETS TRANFERED ALONG FOOD CHAIN AS DIFFERENT ANIMALS EAT EACHOTHER
  • ENERGY LOST AT EACH STAGE USED FOR RESPIRATION WHICH POWERS ALL LIFE PROCESSES
  • MOST OF ENERGY EVENTUALLY LOST TO SURROUNDINGS AS HEAT (ESPECIALLY TRUE FOR MAMMALS - BODIES HAVE TO BE KEPT AT CONSTANT TEMPERATURE - USUALLY HOTTER THAN SURROUNDINGS)
  • MATERIAL AND ENERGY ALSO LOST AS WASTE PRODUCTS - CAN BECOME STARTING POINTS OF OTHER FOOD CHAINS (E.G. HOUSEFLIES EAT FAECES)
  • EGESTION - WHEN FOOD THAT CAN'T BE DIGESTED PASSES OUT AS FAECES
  • EXCRETION - WHEN WASTE PRODUCTS OF BODILY PROCESSES ARE RELEASED
  • MATERIAL AND ENERGY BOTH LOST AT EACH STAGE OF FOOD CHAIN - EXPLAINS PYRAMID OF BIOMAS SHAPE
  • ONLY EVER GET FOOD CHAINS WITH ABOUT FIVE TROPHIC LEVELS - SO MUCH ENERGY LOST AT EACH STAGE THAT THERE IS NOT ENOUGH LEFT TO SUPPORT ANY OTHER ORGANISMS
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B2B - Energy Flow

DATA ON ENERGY FLOW

  • AMOUNT OF ENERGY LOST AT CERTAIN STAGE = ENERGY AVAILABLE TO FIRST LEVEL - ENERGY AVAILABLE TO SECOND LEVEL (E.G. ENERGY AVAILABLE TO A GREENFLY FROM A ROSEBUD IS 80000KJ AND THE ENERGY AVAILABLE TO A LADYBIRD FROM THE GREENFLY IS 10000KJ. ENERGY LOST = 80000 - 10000 = 70000KJ)
  • EFFICIENCY OF ENERGY TRANSFER = (ENERGY AVAILABLE TO NEXT LEVEL / ENERGY THAT WAS AVAILABLE TO PREVIOUS LEVEL) X 100 
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B2C - Recycling

IMPORTANCE OF CARBON

IMPORTANT ELEMENT IN MATERIALS THAT LIVING THINGS ARE MADE FROM

THE CARBON CYCLE

  • PHOTOSYNTHESIS - PLANTS CONVERT CO2 IN AIR INTO SUGARS - CAN THEN INCORPERATE CARBON INTO OTHER CARBS, FATS AND PROTIENS - ONLY WAY CARBON IS USED UP - CYCLE POWERED BY PHOTOSYNTHESIS
  • EATING - PASSES CARBON COMPOUNDS IN PLANT ALONG TO ANIMALS IN FOOD CHAIN
  • RESPIRATION - BOTH PLANTS AND ANIMALS RESPIRE - PUTS CO2 BACK INTO ATMOSPHERE
  • DEATH AND DECAY - PLANS AND ANIMALS - BROKEN DOWN BY BACTERIA AND FUNGI IN SOIL - DECOMPOSERS RELEASE CO2 BY RESPIRATION AS THEY BREAK DOWN MATERIAL
  • FOSSIL FUELS - FORMED FROM MATERIAL OF DEAD PLANTS AND ANIMALS OVER MILLIONS OF YEARS - BURNED TO RELEASE CO2
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B2C - Recycling

WATERLOGGED AND ACIDIC SOILS

  • WATERLOGGED SOILS - DECOMPOSITION SLOWER - RECYCLING OF CARBON TAKES LONGER - BACTERIA AND FUNGI NEED OXYGEN TO RESPIRE AND DECOMPOSE MATERIAL - WATERLOGGED SOIL DON'T HAVE MUCH OXYGEN - DECOMPOSERS HAVE LESS ENERGY - DECOMPOSITION SLOWER
  • ACIDIC SOILS - DECOMPOSITION SLOWER - EXTREMES IN PH SLOW DOWN REPRODUCTION OF DECOMPOSERS OR KILL THEM

THE SEA

  • SEA - MAJOR RECYCLING PATHWAY FOR CARBON
  • MILLIONS OF SPECIES OF MARINE ORGANISMS MAKE SHELLS MADE OF CARBONATE - ORGANISMS DIE AND SHELLS FALL ON OCEAN FLOOR - FORM LIMESTONE ROCKS - CARBON IN ROCKS RETURNS TO ATMOSPHERE AS CO2 DURING VOLCANIC ERUPTIONS OR WHEN ROCKS WEATHERED DOWN 
  • CARBON SINKS - OCEANS CAN ABSORB LARGE AMOUNTS OF CO2 - ACTS AS HUGE STORES OF CARBON
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B2C - Recycling

IMPORTANCE OF NITROGEN

ATMOSPHERE - 78% NITROGEN GAS - NEEDS TO BE TURNED INTO NITRATES - PLANTS NEED NITRATES - MAKE PROTIENS FOR GROWTH

THE NITROGEN CYCLE

  • 1) PLANTS - GET NITROGEN FROM NITRATES IN SOIL - NITROGEN COMPOUNDS PASSED ALONG FOOD CHAIN AS ANIMALS EAT EACHOTHER - ANIMALS PRODUCE WASTE AND DECOMPOSE WHEN DEAD
  • 2) DECOMPOSERS - BREAK DOWN PROTIENS IN DECOMPOSING PLANTS AND ANIMALS AND UREA FROM ANIMAL WASTE INTO AMMONIA
  • 3) NITRIFYING BACTERIA - TURNS AMMONIA FROM DECAYING MATTER INTO NITRATES - RETURNS NITROGEN COMPOUNDS TO SOIL 
  • 4) NITROGEN FIXATION - PROCESS OF TURNING N2 FROM AIR INTO NITROGEN COMPOUNDS WHICH CAN BE USED BY PLANTS - DONE IN TWO WAYS
  • LIGHTNING - ENERGY IN LIGHTNING MAKES MAKES NITROGEN REACT WITH OXYGEN TO FORM NITRATES
  • NITROGEN FIXING BACTERIA - TURNS ATMOSPHERIC CO2 INTO NITRATES THAT PLANTS CAN USE
  • 5) DENITRIFYING BACTERIA - TURNS NITRATES BACK INTO N2 GAS - NO BENEFIT TO LIVING ORGANISMS
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B2D - Interdependence

COMPETITION BETWEEN ORGANISMS

  • ANIMALS MUST COMPETE WITH EACHOTHER FOR THINGS THEY NEED LIKE FOOD, SHELTER AND MATES IN ORDER TO SURVIVE
  • SIMILAR ORGANISMS IN SAME HABITAT - CLOSEST COMP - COMPETING FOR SIMILAR ECOLOGICAL NICHES
  • ECOLOGICAL NICHES - HOW A SPECIES FITS IN TO IT'S ECOSYSTEM - DEPENDS ON WHERE INDIVIDUALS LIVE AND WHAT THEY FEED ON

INTRASPECIFIC COMPETITION

  • ORGANISMS COMPETE FOR RECOURCES AGAINST INDIVIDUALS OF SAME SPECIES
  • BIGGER IMPACT ON ORGANISMS - INDIVIDUALS OF SAME ORGANISMS HAVE SAME NEEDS - WILL COMPETE FOR SAME RECOURCES

INTERSPECIFIC COMPETITION

  • ORGANISMS COMPETE FOR RECOURCES AGAINST INDIVIDUALS OF DIFFERENT SPECIES
  • LESS IMPACT ON ORGANISMS - DIFFERENT NEEDS - COMPETE FOR DIFFERENT RECOURCES
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B2D - Interdependence

PREY AND PREDITOR CYCLES

  • POPULATION OF ANY SPECIES LIMITED BY AMOUNT OF FOOD AVAILABLE
  • POPULATION OF PREY INCREASES - CAUSES POPULATION OF PREDITORS TO INCREASE - MORE FOOD AVAILABLE
  • POPULATION OF PREDITORS INCREASE - CAUSE POPULATION OF PREY TO DECREASE - MORE PREY EATEN
  • PREY AND PREDITOR CYCLES - OUT OF PHASE WITH EACHOTHER - TAKES A WHILE FOR ONE POPULATION TO RESPOND TO CHANGES OF OTHER POPULATION 

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B2D - Interdependence

PARASITIC RELATIONSHIPS

  • PARASITES LIVE OFF HOST - TAKE WHAT THEY NEED TO SURVIVE WITHOUT GIVING ANYTHING BACK - OFTEN HARMS HOST - WIN-LOSE SITUATION
  • E.G. TAPEWORMS ABSORB LOTS OF NUTRIENTS FROM HOST, CAUSING HOST TO SUFFER MALNUTRITION
  • E.G. FLEAS LIVE ON ORGANISMS LIKE DOGS WHICH GAIN NOTHING FROM HAVING FLEAS

MUTUALISTIC RELATIONSHIPS

  • RELATIONSHIP WHERE BOTH ORGANISMS BENEFIT - WIN-WIN RELATIONSHIP
  • E.G. OXPECKERS LIVE ON THE BACK OF BUFFALOS - EAT PESTD OFF BUFFALO AND ALERT IT TO WHEN PREDETORS ARE NEAR BY HISSING
  • E.G. PLANTS POLLINATED BY INSECTS - ALLOWS PLANTS TO REPRODUCE - INSECTS GET NECTAR - CONTAINS SUGAR NEEDED FOR ENERGY

NITROGEN FIXING BACTERIA

SOME LIVE IN SOIL - OTHERS IN NODULES ON ROOTS OF LEGUME PLANTS  - MUTUALISTIC RELATIONSHIP - BACTERIA GETS FOOD FROM PLANT - PLANT GETS NITROGEN COMPOUND TO MAKE PROTEINS 

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B2E - Adaptations

ADAPTATIONS - FEATURES THAT ORGANISMS HAVE TO MAKE THEM BETTER SUITED TO THEIR ENVIRONMENT

ANIMALS THAT ARE ADAPTED ARE BETTER ABLE TO COMPETE FOR RECOURCES - MORE LIKELY TO SURVIVE, REPRODUCE AND PASS ON THESE TRAITS TO OFFSPRING

SPECIALISTS - ORGANISMS WHICH ARE HIGHLY ADAPTED TO LIVE IN A SPECIFIC HABITAT

  • E.G. GIANT PANDAS ADAPTED TO EAT JUST BAMBOO
  • WILL OUTCOMPETE GENERALISTS IN HABITAT WHERE CONDITIONS ARE STABLE - BETTER ADAPTED TO SPECIFIC CONDITIONS

GENERALISTS - ORGANISMS THAT ARE ADAPTED TO SURVIVE IN A RANGE OF DIFFERENT HABITATS

  • E.G. BLACK RATS ABLE TO SURVIVE IN FORESTS, CITIES AND AREAS OF FARMLAND
  • WILL OUTCOMPETE SPECIALISTS WHEN CONDITIONS IN HABITAT ARE LIKELY TO CHANGE - SPECIALISTS WON'T BE ADAPTED TO NEW CONDITIONS - GENERALISTS ADAPTED TO RANGE OF CONDITIONS - MORE LIKELY TO SURVIVE
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B2E - Adaptations

 ADAPTATIONS OF SUCCESSFUL PREDETORS

  • BINOCULAR VISION - HELPS JUDGE SIZE AND DISTANCE WELL
  • BUILT FOR SPEED - HELPS THEM CATCH UP WITH PREY
  • SHARP TEETH AND CLAWS - HELPS THEM KILL PREY
  • CAMOFLAUGE - HELPS THEM AVOID BEING SEEN BY PREY 

ADAPTATIONS FOR SUCCESSFUL PREY

  • LIVE IN GROUPS - INTIMIDATING FOR PREDETOR AND OFFERS PROTECTION
  • BUILT FOR SPEED - HELPS THEM RUN AWAY FROM PREDITOR
  • EYES ON SIDE OF HEAD - GIVES THEM WIDE FIELD OF VIEW
  • CAMOFLAUGE AND DEFENCES SUCH AS POISEN AND STINGS - HELPS THEM AVOID BEING SEEN BY PREDITOR AND, IF SEEN ALLOWS THEM TO DEFEND THEMSELVES MORE EFFECTIVELY
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B2E - Adaptations

ADAPTATIONS FOR COLD ENVIRONMENT

ADAPTATION FOR COLD ENVIRONMENT BASED ON REDUCING HEAT LOSS

ANATOMICAL ADAPTATIONS

THICK COAT OR LAYER OF BLUBBER TO INSULATE BODY AND TRAP HEAT IN
LARGE SIZE AND COMPACT BODY - SMALL SURFACE AREA TO VOLUME RATIO - REDUCE HEAT LOSS THROUGH SURFACE OF SKIN
COUNTER-CURRENT HEAT EXCHANGE SYSTEMS E.G. PENGUINS HAVE TO STAND ON COLD ICE ALL DAY - BLOOD VESSELS TO AND FROM FEET CARRY BLOOD THAT FLOWS IN OPPISITE DIRECTIONS - VESSELS PASS CLOSE TO EACHOTHER ALLOWING HEAT TO TRANSFER BETWEEN THEM - WARM BLOOD FLOWING TOWARDS FEET HEATS UP COLD BLOOD FLOWING AWAY FROM FEET THAT'S RETURNING TO HEART AND VEINS - FEET STAY COLD BUT REST OF BODY STAYS WARM

BEHAVIOURAL ADAPTIONS

  • MIGRATION TO WARMER CLIMATES IN COLD MONTHS - AVOID HAVING TO COPE WITH COLD CONDITIONS
  • HIBERNATIONS DURING WINTER MONTHS - SAVES ENERGY - ANIMAL DOESN'T HAVE TO FIND FOOD
  • HUDDLE TOGETHER TO KEEP WARM
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B2E - Adaptations

ADAPTAIONS TO HOT ENVIRONMENTS

BASED ON INCREASING HEAT LOSS AND REDUCING HEAT GAIN

BEHAVIOURAL ADAPTATIONS

  • ANIMALS SPEND DAY IN SHADE OR UNDERGROUND TO AVOID HEAT AND ARE OFTEN MORE ACTIVE AT NIGHT
  • INCREASE HEAT LOSS BY BATHING IN WATER - WATER EVAPORATES AND TRANSFERS HEAT FROM SKIN TO SURROUNDINGS - COOLS ANIMAL DOWN

ANATOMICAL ADAPTATIONS

  • SMALL - LARGE SURFACE AREA TO VOLUME RATIO - MORE BODY HEAT LOST TO SURROUNDINGS
  • LARGE THIN EARS - REDUCE SURFACE AREA TO VOLUME RATIO - ALLOW MORE BLOOD FLOW AT SURFACE OF SKIN
  • STORE FAT AT JUST ONE PART OF BODY - STOPS REST OF BODY BEING TOO WELL INSULATED - INCREASES HEAT LOSS
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B2E - Adaptations

ADAPTATIONS TO DRY ENVIRONMENTS - MINIMISE AMOUNT OF WATER LOST TO ENVIRONMENT

DESERT PLANTS

  • SMALL SURFACE AREA TO VOLUME RATIO - MINIMISE WATER LOSS FROM SURFACE
  • CUTICLE - THICK WAXT LAYER - SPINES INSTEAD OF LEAVES - FURTHER REDUCE WATER LOSS
  • STORE WATER IN STEMS - ALLOWS THEM TO SURVIVE IN TIMES OF EXTREME DROUGHT
  • SHALLOW BUT VERY EXTENSIVE ROOTS - ENSURES WATER IS ABSORBED QUICKELY OVER LARGE SURFACE AREA

DESERT ANIMALS

  • SPECIALISED KIDNEYS - PRODUCE CONCERNTRATED URINE WITH LOW WATER CONTENT
  • NO SWEAT GLANDS - PREVENTS WATER LOSS THROUGH SWEATING
  • SPEND LOTS OF TIME IN UNDERGROUND BURROWS - AIR CONTAINS MORE MOISTURE THAN AIR ON SURFACE
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B2E - Adaptations

BIOCHEMICAL ADAPTIONS

  • EXTREMOPHILES - ORGANISMS THAT CAN TOLERATE EXTREME CONDITIONS E.G.HIGH TEMPERATURES, PH
  • E.G. EXTREMOPHILE BACTERIA LIVE IN VERY HOT ENVIRONMENT - HAVE ENZYMES THAT WORK BETTER AT MUCH HIGHER OPTIMUM TEMPERATURES - ABLE TO FUNCTION NORMALLY AT TEMPERATURES WHICH WOULD DENATURE NORMAL ENZYMES
  • E.G. ORGANISMS THAT LIVE IN VERY COLD ENVIRONMENT HAVE ANTIFREEZE PROTEINS - INTERFERE WITH FORMATION AND GROWTH OF ICE CRYSTALS IN CELLS - STOPS CELLS BEING DAMAGED BY ICE

 SURFACE AREA TO VOLUME RATIO

  • WAY OF COMPARING HOW MUCH SURFACE AREA SOMETHING HAS COMPARED TO ITS SIZE
  • SMALL OBJECTS - LARGER SURFACE AREA TO VOLUME RATIO - 1CM2 CUBE HAS A SURFACE AREA OF 6CM SO ITS RATIO WOULD BE 6:1
  • LARGE OBJECTS - SMALLER SURFACE AREA TO VOLUME RATIO - 8CM2 CUBE HAS A SURFACE AREA OF 24CM SO ITS RATIO WOULD BE 24:8 OR 3:1
  • LARGE ORGANISMS LOSE LESS HEAT BECAUSE OF THEIR SMALLER SURFACE AREA TO VOLUME RATIO - USUALLY LIVE IN COLDER PLACES
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B2F - Natural Selection

CHARLES DARWIN'S THEORY OF NATURAL SELECTION

  • ORGANISMS IN A SPECIES SHOW WIDE VARIATION AND ORGANISMS COMPETE FOR LIMITED RECOURCES IN AN ECOSYSTEM
  • ORGANISMS THAT ARE BEST ADAPTED - MORE SUCCESSFUL COMPETITORS - MORE LIKELY TO SURVIVE - SURVIVAL OF THE FITTEST
  • ORGANISMS THAT SURVIVE - MORE LIKELY TO REPRODUCE - PASS ON SUCCESSFUL ADAPTATIONS TO OFFSPRING - ORGANISMS LESS ADAPTED - LESS LIKELY TO SURVIVE AND REPRODUCE AND PASS ON CHARACTERISTICS
  • OVER TIME SUCCESSFUL ADAPTATIONS GET MORE COMMON IN SPECIES - POPULATION EVOLVES

NEW DISCOVERIES

  • ORIGIONAL THEORY COULDN'T GIVE EXPLAINATION FOR WHY NEW CHARACTERISTICS APPEARED OR EXACTLY HOW INDIVIDUAL ORGANISMS PASSED ON SUCCESSFUL ADAPTATIONS TO ORGANISMS
  • DNA DISCOVERED 50 YEARS LATER - EXPLAIN HOW GENES CONTROL ADAPTATIONS - ARISE FROM MUTATIONS IN GENES AND PASSED TO FUTURE GENERATIONS IN GENES PARENTS CONTRIBUTE TO OFFSPRING
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B2F - Natural Selection

SPECIATION - ORGANISMS IN SPECIES CHANGING SO MUCH OVER LONG PERIOD OF TIME THAT NEW SPECIES IS FORMED - HAPPENS WHEN POPULATIONS OF SAME SPECIES CHANGE ENOUGH TO BECOME REPRODUCTIVELY ISOLATED

  • REPRODUCTIVE ISOLATION - ORGANISM CAN'T INTERBREED TO PRODUCE FERTILE OFFSPRING - CAUSED BY GEOGRAPHIC ISOLATION:
  • PHYSICAL BARRIER DIVIDES POPULATION OF SPECIES - TWO NEW POPULATIONS UNABLE TO MIX
  • DIFFERENT MUTATIONS CREATE NEW FEATURES IN TWO GROUPS OF ORGANISMS
  • NATURAL SELECTION WORKS - IF MUTATIONS BENEFIT ORGANISMS IT IS SPREAD THROUGH EACH POPULATION
  • CONDITIONS ON EACH SIDE OF BARRIER SLIGHTLY DIFFERENT - BENEFICIAL FEATURES DIFFERENT
  • INDIVIDUALS WILL EVENTUALLY DEVELOP FEATURES SO DIFFERENT FROM THE OTHER POPULATION THAT THEY WON'T BE ABLE TO INTERBREED TO CREATE FERTILE OFFSPRING
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B2F - Natural Selection

REASONS AGAINST DARWINS THEORY

  • FIRST POSSIBLE EXPLAINATION OF EXISTANCE WITHOUT NEED OF CREATOR - WENT AGAINST COMMON RELIGIOUS BELIEFS
  • COULDN'T EXPLAIN WHY USEFUL CHARACTERISTICS APPEARED OR WHY THEY WERE INHERITED
  • WASN'T ENOUGH EVIDENCE TO CONVINCE MANY SCIENTISTS - NOT MANY OTHER STUDIES HAD BEEN DONE

LAMARCK'S CONFLICTING THEORY OF EVOLUTION

  • CHARACTERISTICS COMMONLY USED BY AN ANIMAL WILL BECOME MORE DEVELOPED - ACQUIRED CHARACTERISTICS CAN BE PASSED ON TO OFFSPRING
  • THEORY REJECTED - CONCLUDED THAT ACQUIRED CHARACTERISTICS DON'T HAVE GENETIC BASIS - CAN'T BE PASSED ON TO OFFSPRING

NATURAL SELECTION WIDELY ACCEPTED

  • BEEN DEBATED AND TESTED BY WIDE RANGE OF SCIENTIST - NO CONCLUSIVE PROOF AGAINST THEORY
  • OFFERS PLAUSABLE EXPLAINATION FOR A LOT OF OBSERVATIONS OF PLANTS AND ANIMALS E.G. BEHAVIOURAL PATTERMS
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B2G - Population and Pollution

RESULTS OF EXPONENTIALLY INCREASING POPULATION

BIRTH RATE HIGHER THAN DEATH RATE - POPULATION INCREASING - MORE RECOURCES BEING USED UP - MORE POLLUTION PRODUCED E.G. CO2 AND SULFUR DIOXIDE, HOUSEHOLD PULLUTION LIKE TOXIC METALS, SEWAGE

HIGHER STANDARD OF LIVING IN DEVELOPED COUNTRIES - DEMANDS EVEN MORE ENVIRONMENTAL RECOURCES - MEDC ONLY HAVE SMALL PROPORTION OF WORLDS POPULATION BUT CAUSE LARGE PROPORTION OF WORLDS POLLUTION

RESULTS OF INCREASING AMOUNTS OF POLLUTION

GLOBAL WARMING - FOSSIL FUELS BURNED AND RELEASE GREENHOUSE GAS - TRAPS HEAT INSIDE ATMOSPHERE - SCIENTISTS PREDICT THIS CAUSING SEA LEVEL TO RISE, WEATHER SYSTEMS TO BECOME LESS PREDICTABLE AND AGRICULTURAL SYSTEMS TO FAIL - PEOPLE MEASURING AMOUNT OF GAS GIVEN OFF TO REDICE EMISSIONS

ACID RAIN - FOSSIL FUELS BURNED PRODUCE SULFUR DIOXIDE - COLLECTS AS SULPHURIC ACID - FALLS AS ACID RAIN - HARMS WILDLIFE BY CAUSING LAKES TO BECOME MORE ACIDIC, CREATING UNBEARABLE PH FOR ECOSYSTEM TO FUNCTION, DESTROYS BUILDINGS

OZONE DEPLETION - CFC BREAK DOWN OZONE - ALLOWS HARMFUL UV RAYS TO EARTH - SKIN CANCER AND KILLS PLANKTON - MASSIVE EFFECT ON SEA ECOSYSTEM - PLANKTON AT BOTTOM OF FOOD CHAIN - INTERNATIONAL BAN OF CFC'S

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B2G - Population and Pollution

INDICATOR SPECIES

  • TELL IF AREA IS POLLUTED OR NOT BY LOOKING AT INDICATOR SPECIES - CAN ONLY SURVIVE IN UNPOLLUTED CONDITIONS
  • E.G. LICHENS USED TO MONITOR AIR QUALITY - CLEANER AIR, GREATER DIVERSITY OF LICHENS SURVIVE
  • E.G. MAYFLY LARVAE USED TO MONITER WATER QUALITY - CAN'T SURVIVE IN POLLUTED WATER
  • E.G. WATERLICE, RAT-TAILED MAGGOTS AND SLUGWORMS ONLY SURVIVE IN POLLUTED WATER - MORE OF THE SPECIES MEANS MORE POLLUTED WATER

MEASURING POLLUTION LEVEL

  • INDICATOR SPECIES - SIMPLE SURVEY - SEE IF SPECIES PRESENT OR ABSENT - CAN'T TELL HOW POLLUTED
  • - COUNT NUMBER OF SPECIES THAT OCCURS IN AREA TO GIVE NUMERICAL VALUE - MEASUREMENTS OF AREAS CAN BE COMPARED
  • DIRECT MEASUREMENT - SENSITIVE INSTRUMENTS MEASURE CONCENTRATIONS OF CHEMICAL POLLUTANTS
  • - SATELLITE DATA INDICATES POLLUTANT LEVEL E.G. CAN SHOW WHERE OZONE IS THIN OR ABSENT
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B2G - Population and Pollution

LIVING METHODS

  • ADVANTAGES - RELATIVELY QUICK, EASY AND CHEAP - NO EXPENSIVE EQUIPMENT OR HIGHLY TRAINED WORKERS NEEDED
  • DISADVANTAGES - FACTORS OTHER THAN POLLUTION E.G. TEMPERATURE CAN INFLUENCE SURVIVAL OF SPECIES - NOT ALWAYS RELIABLE

NON-LIVING METHODS

  • ADVANTAGES - GIVES RELIABLE, NUMERICAL DATA - EASY TO COMPARE WITH OTHER MEASUREMENTS
  • - EXACT POLUTANTS CAN BE IDENTIFIED
  • DISADVANTAGES - OFTEN REQUIRE MORE EXPENSIVE EQUIPMENT AND TRAINED WORKERS
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B2H - Sustainability

REASONS FOR ENDANGERED SPECIES

  • CLIMATE CHANGE AND POLLUTION  - SPECIES UNABLE TO ADAPT TO CHANGES IN CLIMATE E.G. PH, TEMP
  • HABITAT DESTRUCTION - CAN'T FIND FOOD AND SHELTER IF THERE AREN'T ENOUGH SUSTAINABLE HABITATS
  • HUNTING - LESS INDIVIDUALS, LESS LIKELY TO FIND MATES AND REPRODUCE - GENE POOL LOWER - WON'T BE MUCH GENETIC VARIATION
  • COMPETITION - MORE ANIMALS COMPETING FOR SAME THINGS - LESS WILL GET WHAT THEY NEED TO LIVE

SUSTAINABLE DEVELOPMENT - PROVIDING FOR NEEDS OF TODAYS INCREASING POPULATION WITHOUT HARMING ENVIRONMENT

  • NEEDS TO BE CAREFULLY PLANNED AND CARRIED OUT OVER WHOLE PLANET
  • E.G. FISHING QUOTAS INTRODUCED - PREVENT SOME TYPES OF FISH BEING CAUGHT AND KILLED 
  • E.G. LAWS INSISTING LOGGING COMPANIES REPLANT TREES THEY CUT DOWN - SUSTAINABLE PRODUCTION OF WOOD AND PAPER
  • EDUCATION IMPORTANT - PEOPLE AWARE OF PROBLEMS - MORE LIKELY TO HELP 
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B2H - Sustainability

WHALES

  • HAVE COMMERCIAL VALUE WHEN ALIVE AND DEAD
  • TOURIST ATTRACTION - HELP COUNTRIES MAKE MONEY FROM TOURISM
  • WHALE MEAT AND OIL USED AND COSMETICS MADE FROM WAXY SUBSTANCE IN INTESTINES
  • INTERNATIONAL WHALIN COMISSION STRUGGLED TO GET NATIONS TO RESTRICT WHALING - 1982 - MEMBER DECLARED STOP TO WHALING - ONLY EXCEPTION BEING NORWAY AND CULLING ALLOWED TO BE CARRIED OUT IN JAPAN
  • HARD TO CHECK - IWC DOESN'T HAVE AUTHORITY TO ENFORCE PUNISHMENT - ILLEGAL WHALING HAPPENS
  • SOME WHALES KEPT IN CAPTIVITY - DIFFERENT VIEWS:
  • DON'T HAVE MUCH SPACE IN CAPTIVITY AND USED FOR ENTERTAINING PEOPLE - SOME THINK IT'S WRONG TO PREVENT WHALES FROM LIVING A HAPPIER LIFE IN THE WILD FOR BENEFIT OF HUMANS
  • CAPTIVE BREEDING PROGRAMMES - WHALES BRED IN NUMBERS AND RELEASED BACK INTO WILD
  • RESEARCH ON CAPTIVE WHALES - HELP UNDERSTAND NEEDS - HELP CONSERVATION - A LOT WE DON'T UNDERSTAND ABOUT THEM E.G. COMMUNICATION
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B2H - Sustainability

EVALUATING SUCCESS OF CONSERVATION PROGRAMMES

  • GENETIC VARIATION - SPECIES BEING CONSERVED SHOULD HAVE ENOUGH VARIATION TO SURVIVE APPEARENCE OF DISEASE AND COPE WITH CHANGES IN ENVIRONMENT
  • VIABILITY OR POPULATIONS - SHOULD HAVE MALES AND FEMALES OF AGE TO REPRODUCE - LARGE ENOUGH TO PREVENT INTERBREEDING
  • AVAILABLE HABITATS - RIGHT TYPE PF HABITAT TO LIVE IN - IMPORTANT IF SPECIES IS SPECIALISED
  • INTERACTION BETWEEN SPECIES - SPECIES INTERACT AS THEY WOULD IN NATURAL ENVIRONMENT

BENEFITS OF CONSERVATION PROGRAMMES

  • PROTECTING HUMAN FOOD SUPPLY - OVERFISHING REDUCED FISH STOCKS - CONTROL ENSURES THERE'S ENOUGH FISH TO EAT FOR FUTURE GENERATIONS
  • ENSURING MINIMAL DAMAGE TO FOOD CHAINS - EXTINCT SPECIES WILL EFFECT ALL ORGANISMS ABOVE IT IN FOOD CHAIN
  • FUTURE MEDICINES - PLANTS THAT PROVIDE MEDICINE CAN'T BECOME EXTINCT
  • CULTURAL ASPECTS - INDIVIDUAL SPECIES MAY BE IMPORTANT TO PARTICULAR NATION - RESPECT THIS
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