Alien Physiology, Convergent Evolution, and f c Recap N = N * f s f - PowerPoint PPT Presentation

Alien Physiology, Convergent Evolution, and f c

Recap N = N * f s f GHZ f p n H f l f J f ƒ f Eu f m f i f c L/T • N * = 4 x 10 11 • f s = 0.2 • f GHZ = 0.002 • f p = 1.0 • n H = 2 • f l = 1.0 • f J = 0.5 • f ƒ = 0.01 • f Eu = 0.1 • f m = 0.1 • f i = 0.3 N = 4.8 x 10 3

Necessities of Life • Energy – What does it eat? – How does it eat? • Reproduction • Senses – What senses are important? – Communication • Motility

Convergent Evolution • Evolutionarily useful traits evolve among unrelated animals. • Manipulative organs: • Primate hands • Bird beaks • Elephant trunks • Cephalopod tentacles • The eye has evolved >65 times, with 10 different designs. • The mammalian eye evolved from brain tissue. • The cephalopod eye evolved from skin tissue.

Will Intelligent Aliens be Humanoids?

What might a Martian look like? Let’s build an alien …

Technology If we expect to make contact and communicate, (unless we can travel to their planet), they must have communications technology (e.g., radio) f c is fraction of intelligent creatures that develop communications technology

Intelligence and Technology Must intelligent creatures develop technology? Can you generate technology without manipulative organs (e.g., hands)?

Technology and Culture • Must intelligent life form societies , and have cultures ? • Some insects are social, and keep farms. • Many mammals, and most primates, are social. • Is a society required for the development of technology? • Some primates and birds use tools.

N update N = N * f s f GHZ f p n H f l f J f ƒ f Eu f m f i f c L/T • N * = 4 x 10 11 • f s = 0.2 • f GHZ = 0.002 • f p = 1.0 • n H = 2 • f l = 1.0 • f J = 0.5 • f ƒ = 0.01 • f Eu = 0.1 • f m = 0.1 • f i =0.3 • f c =0.1 N = 480