Adaptive Radiation

• Adaptive radiation is the evolutionary process by which an ancestral species gives rise to multiple descendant species that occupy different ecological niches.
• The adaptive radiation of Darwin's finches on the Galapagos Islands provides evidence for natural selection, as it shows how birds with beaks adapted to their specific food sources have evolved over time.
• Leads to the emergence of diverse forms, each adapted to specific environmental conditions.
• What is the A in adaptive Radiation?

  Sources of Ecological opportunity
• What is the b in adaptive Radiation?

  
  

  Release from natural selection
• What is the c in adaptive Radiation?

  
  

  Ecological Release
• What is the D in adaptive Radiation?

  Rapid specialization and morphological diversification
• What are the three points in ecological opportunity?

  Key innovation, New habitat, Antagonist Extinction
• 3 results of ecological release?

  Increased trait variation, Density compensation, Broader habitat or resource use
• The diversification of Darwin's finches is primarily attributed to natural selection acting on variations in beak morphology driven by food availability.
• The HAWAIIAN HONEYCREEPERS has diverse beak shapes, feeding behaviors, colors, and habitat preferences
• LAKE MALAWI CICHLIDS have laterally compressed bodies, strong jaws, and specialized teeth for scraping algae from rocks.
• LAKE VICTORIA CICHLIDS exhibiting elongated bodies adapted for foraging in open water
• Mammals possess key evolutionary traits such as endothermy (warm-bloodedness), fur/hair, live birth, and mammary glands for nursing offspring.
• THE AMNIOTIC EGG Perhaps one of the greatest key innovations of all time
• ARBOREAL ADAPTATION Tree dwelling reptiles like geckos, calotes and

  chameleon, Development of adhesive pads for climbing, digit modification (syndactyly), prehensile limbs & tail
• AERIAL ADAPTATION

  Pterosaurs (ancient reptiles) adapted to aerial life

  Developed wings with a patagium

  Achieved significant size, with wingspans reaching up to 6 meters

  Draco (modern lizard) possesses a patagium aiding in passive flight with lateral extensions of skin
• AQUATIC ADAPTATION

  Ancient reptiles moved to water

  Aquatic adaptations in living reptiles (turtles, crocodiles)

  Paddle-like limbs, laterally compressed tail

  Hydrophis (sea snake) adaptations
• FOSSORIAL

  ADAPTATION

  Reptilian burrowing

  ex: tuatara and turtles

  strong muscles and skull

  respiratory adaptations

  thermoregulation

  Found in Africa, America, Australia
• One signature of an adaptive radiation is a burst of diversification over a relatively short period of time