UNIT 3 - EVOLUTION 3 ½ - 4 weeks … test around Nov. 23 rd Evaluation:Evaluation: –2 Quizzes, Written Test –Ind. Study Work … working in library or on own

Adaptation & Variation

Extinction To completely disappear from Earth Results when species either lack diversity and/or the ability to change within their environment Eg. Dodo bird, etc.

Adaptations Helps an organism survive & reproduce Can be structural, behavioural or a physiological process

Adaptations 1.Structural Too many to name –Owls (talons, eyesight); sharks (sensory organs, teeth, graceful swimmers); bats (sonar); humans (brain, bipedal, thumbs), etc. Includes camouflage (stick insect, octopus…)

Adaptations Video: CamouflageCamouflage

Mimicry A special structural adaptation Harmless creatures posing as harmful species in either colour or structure Tricks predators into believing the critter is untasty Eg. Viceroy butterfly, king snake

Mimics

Mimicry Video: Animal ImpostersAnimal Imposters

Adaptations 2.Behavioural Things that animals do, not what they have Eg. Meerkats standing, bird calls, migration,

Japanese honey bee adaptation Video: “Hornets from hell”Hornets from hell

Adaptations 3.Physiological Hibernation –Bears can overwinter when food is scarce; ground squirrels can avoid harsh winters Tanning Lactic Acid fermentation (low O 2 )

How do Adaptations Develop? Gradual, accumulative changes over generations Random, heritable mutations in DNA Variations → differences between individuals (structural or physiological) Not all variations become adaptations

African Cichlids

Interactions with Environment Very important to adaptation & variation Climates change; floods, droughts and famines occur Human activities – deforestation, agriculture change landscapes Unimportant characteristics may eventually become crucial for survival if things change

Saguaro cactus Fleshy stem holds water Most roots < 15cm deep but cover huge area Can absorb 750 L of water in a single storm Leaves reduced to spines to reduce transpiration rate Spines also ↓ predation Stomata only open at night

Variation to Adaptation The English Peppered Moth Light peppered colour and black Historically black was rare – lichen on trees in England was light coloured and moths were easy targets for birds Industrial Revolution killed lichen and put soot on trees; 50 years later 95% of Manchester moths were black

English Peppered Moth Pre-industrial revolution Post-industrial revolution

Peppered Moth Applet Fun in 17 th century England! Click hereClick here

Questions 1.Sharks have an excellent sense of smell. Is this a variation or an adaptation? 2.A black and yellow insect buzzes around you, causing you to freak out. When it lands you see that it is only a fly. What is the fly’s adaptation and explain the advantage. 3.When could genetic variation have no significant effect on a species’ survival?

Mutations Changes in genetic material (DNA) New alleles = genetic variation Eg. Your DNA has about 175 mutations compared to your parents’ Could be harmful or beneficial In somatic cells → tumour In gametic cells → may be passed on

Selective advantage A genetic advantage of one organism over its competitors Helps it to survive changing environmental conditions Eg. Water flea surviving in warmer water temperatures

Antibiotic Resistance Staphylococcus aureus (bacteria) can reproduce every 30 minutes Adaptation can occur very quickly Treatment of Staph. Infections can be inhibited by the adaptive bacteria Populations of bacteria with the new allele can create antibiotic resistance