EVIDENCE FOR EVOLUTION

• FOSSILS:

  • EVIDENCE for EVOLUTION
  • REMAINS of ORGANISMS from MILLIONS of YEARS
  • Found in ROCKS
• HOW DO FOSSILS FORM?

  • Parts of an ORGANISM -> haven't DECAYED (conditions needed are absent e.g. lack of water, oxygen, low TEMPERATURE)
  • Parts of an ORGANISM are replaced by MINERALS
  • PRESERVED traces of ORGANISM e.g. footprints, burrows, plant ROOTS
• PROBLEMS:

  • First organisms: Soft bodied "no SKELETON , SHELL"
  • RARELY form fossils -> destroyed to ROCKS in the Earth's CRUST
• EXTINICTION:

  • When there are NONE remaining of a particular SPECIES

  CAUSES:

  • CATASTROPHIC event e.g. ASTEROID killing DINOSAURS
  • New DISEASES / PREDATORS
  • Environmental CHANGES
  • New more SUCCESSFUL species -> COMPETITION
• BACTERIA:

  • EVOLVE rapidly as the REPRODUCE at a FAST rate
  • Use ANTIBIOTICS to treat bacterial DISEASES , or in FARMING
  • Certain STRAINS -> no longer KILLED by ANTIBIOTICS -> antibiotic RESISTANT (e.g. MRSA)
• MUTATIONS:

  • MUTATIONS of BACTERIAL pathogen -> new STRAINS
  • Some are not killed -> SURVIVE and REPRODUCE
  • Therefore the POPULATION of the STRAIN rises -> SPREAD -> people are not IMMUNE -> no effective TREATMENT
• REDUCTION OF STRAINS:

  • Doctors -> shouldn't prescribe antibiotics INAPPROPRIATELY e.g. for a VIRUS
  • Patients should FINISH their full COURSE of ANTIBIOTICS so all of the bacteria are KILLED and none SURVIVE and MUTATE
  • Restrict use in FARMING
• NEW ANTIBIOTICS:

  • EXPENSIVE , take time to DEVELOP
  • New RESISTANT bacteria -> unable to keep UP