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UNIT 3 - EVOLUTION

UNIT 3 - EVOLUTION. 3 ½ - 4 weeks … test around Nov. 23 rd Evaluation: 2 Quizzes, Written Test Ind. Study Work … working in library or on own. Adaptation & Variation. Extinction. To completely disappear from Earth

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UNIT 3 - EVOLUTION

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

  2. Adaptation & Variation

  3. 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.

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

  5. Adaptations • 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…)

  6. Adaptations • Video: Camouflage

  7. 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

  8. Mimics

  9. Mimicry • Video: Animal Imposters

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

  11. Japanese honey bee adaptation • Video: “Hornets from hell”

  12. Adaptations • Physiological • Hibernation • Bears can overwinter when food is scarce; ground squirrels can avoid harsh winters • Tanning • Lactic Acid fermentation (low O2)

  13. 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

  14. African Cichlids

  15. 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

  16. 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

  17. 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

  18. English Peppered Moth Pre-industrial revolution Post-industrial revolution

  19. Peppered Moth Applet • Fun in 17th century England! Click here

  20. Questions • Sharks have an excellent sense of smell. Is this a variation or an adaptation? • 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. • When could genetic variation have no significant effect on a species’ survival?

  21. 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

  22. 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

  23. 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

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