Biology - Module 1b

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Wide feet for spreading

body weight over soft

shifting sand.

How is a camel adapted to life in a very hot, dry climate?

Fat is stored in the hump.

There is no other body fat

to prevent overheating.

How are camels adapted?How are camels adapted?

Brown coat for camouflage.

Long, thin legs mean the

body surface area is large

compared to volumeto increase heat loss.

Loses little water throughsweating or urine.



Leaves are narrow spines

that reduce water loss and

protect from predators.

Stores water in fleshy stem.

How is a cactus adapted?How is a cactus adapted?

Thick, waxy surface

to reduce water loss.

How is a cactus adapted to life in a very hot, dry climate?

Plant surface area is

small compared to volume

to reduce water loss.Some have shallow,

spreading roots for surface

water, others

have deep roots.



Two Types of ReproductionTwo Types of Reproduction

SexualSexual AsexualAsexual

Number of parentsNumber of parents 22 11

Variation orVariation or

clones?clones?VariationVariation Clones (geneticallyClones (genetically

identical)identical)

AdvantageAdvantage Variation givesVariation givesevolutionaryevolutionary

advantagesadvantages

Energy efficient,Energy efficient,keeps desiredkeeps desired

characteristicscharacteristicsDisadvantageDisadvantage Requires moreRequires more

energyenergy

Less resistance toLess resistance to

diseasedisease



© Boardworks Ltd 2004

Chromosomes and Genes

Chromosomes are long strands of genetic informationlocated in the nuclei of cells. They are made of DNA

A gene is a sectionof DNA that carriesthe instructions for agenetic characteristic

We inherit 23chromosomes from

each parent





Embryo TransferEmbryo Transfer



Therapeutic CloningTherapeutic Cloning



Reproductive CloningReproductive CloningC2 Cloning



Genetic EngineeringGenetic Engineering

Bacteria used to produce human insulinBacteria used to produce human insulinfor diabeticsfor diabetics



Theories of EvolutionTheories of Evolution

LamarckLamarck– Plants and animals changed to suit theirPlants and animals changed to suit their

surroundings e.g. giraffes stretched theirsurroundings e.g. giraffes stretched their

necksnecksDarwinDarwin

– Survival of the fittest by natural selectionSurvival of the fittest by natural selection

– Evidence from the fossil recordEvidence from the fossil record



Natural Selection - DarwinNatural Selection - Darwin

Evolution is the change in a population over a longEvolution is the change in a population over a longperiod of time to create a new species.period of time to create a new species.

Individuals in a population show variation (they haveIndividuals in a population show variation (they havedifferences).differences).

There is competition between individuals for food andThere is competition between individuals for food andmates. There is also predation and disease. Thismates. There is also predation and disease. Thiskeeps numbers within a population constant.keeps numbers within a population constant.

Individuals within a species that are better adaptedIndividuals within a species that are better adapted

to their environment are more likely to survive andto their environment are more likely to survive andbreed.breed. These best adapted animals or plants pass on theirThese best adapted animals or plants pass on their

genes to their offspring.genes to their offspring.



Extinction – the loss of a speciesExtinction – the loss of a species

TheThe environmentenvironment where they live changeswhere they live changese.g. a temperature or pH change.e.g. a temperature or pH change.

AA predatorpredator eats the whole species e.g.eats the whole species e.g.

hunted by humans.hunted by humans.A species is killed off byA species is killed off by diseasedisease e.g.e.g.

plants dying from a fungal infectionplants dying from a fungal infection

A more successfulA more successful competitorcompetitor appearsappearse.g. humanse.g. humans







Land and Water PollutionLand and Water Pollution

SewageSewage– Causes diseases such as gastroenteritis and Weil’sCauses diseases such as gastroenteritis and Weil’s

diseasedisease

FertilisersFertilisers– Can get washed into rivers and lakes causing plantsCan get washed into rivers and lakes causing plants

to grow, they die and decomposing bacteria use upto grow, they die and decomposing bacteria use upoxygenoxygen

Toxic ChemicalsToxic Chemicals– Pesticides e.g. DDT can accumulate in the foodPesticides e.g. DDT can accumulate in the food

chainchain



Acid RainAcid Rain



Acid RainAcid Rain

Burning coal releases sulphur whichBurning coal releases sulphur whichforms sulphur dioxide in the atmosphere.forms sulphur dioxide in the atmosphere.

Sulphur dioxide dissolves in rainwater.Sulphur dioxide dissolves in rainwater.Acid rainAcid rain

– strips waxy layer from leaves, removesstrips waxy layer from leaves, removesminerals from the soilminerals from the soil

– erodes statueserodes statues– poisons rivers and lakespoisons rivers and lakes



DeforestationDeforestation

Is the permanent removal of forestsIs the permanent removal of forestsHappens to:Happens to:

– Provide timber and building materialsProvide timber and building materials– Clear land for agriculture and farmingClear land for agriculture and farming

Effects:Effects:

– Forests remove COForests remove CO22 by photosynthesis soby photosynthesis soless COless CO22 removed adding to global warmingremoved adding to global warming

– Burning trees adds to levels of COBurning trees adds to levels of CO22



Greenhouse EffectGreenhouse Effect





Pollution IndicatorsPollution Indicators

Lichens are used as indicators of sulphurLichens are used as indicators of sulphurdioxide air pollutiondioxide air pollution– High levels of sulphur dioxide = no lichenHigh levels of sulphur dioxide = no lichen

– No sulphur dioxide = lots of lichenNo sulphur dioxide = lots of lichen

Invertebrate animals are used asInvertebrate animals are used asindicators of water pollutionindicators of water pollution– E.g. mosquito larva, freshwater shrimpE.g. mosquito larva, freshwater shrimp



SustainabilitySustainability

Development without destroying theDevelopment without destroying theworld.world.– Reduce, reuse, recycleReduce, reuse, recycle

– Energy efficient homes e.g. well insulatedEnergy efficient homes e.g. well insulated

– Using less fossil fuels – use more renewableUsing less fossil fuels – use more renewableenergiesenergies

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Biology - Module 1b