Charles Darwin, aged 7yrs 1

Aged 25yrs 2

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Natural selection – the survival of the “fittest.” How long necks evolved in giraffes. What would happen to the giraffes with shorter necks? Discuss. 10

Natural selection – the survival of the “fittest.” Why might the brown beetles have survived? Discuss. (See notes) 11 11

Natural Selection Darwin wrote extensively about the Galapagos finches, which he studied while on a research voyage on the HMS Beagle. He carefully observed and noted that the variation in the beak structures of the finches had created certain advantages or distinctions in their quest for food. For instance, some beaks were designed for crushing seed shells, whereas others for catching insects. He is most closely associat 12 12

Can you spot the difference? Discuss. Darwin's finches Darwin's finches or Galapagos finches (gulä'pugōs") [key], species of small finches, constituting the subfamily Geospizinae of the finch family. This group of thirteen species is confined to the Galápagos Islands, except a single species found on Cocos Island, about 600 mi (960 km) northeast. Their special adaptations to various habitats were important evidence considered by Charles Darwin in formulating the theory of evolution; they are a striking example of adaptive radiation. Geographically isolated and without competition from similar species, these finches developed distinctive anatomy (particularly beak size and shape) and behaviors, with each species exploiting a unique feeding niche. The bill is adapted in the different species for different purposes, such as crushing seeds, pecking wood, and probing flowers for nectar. The woodpecker finch, Cactospiza pallida, an insect-eater, holds twigs and cactus spines in its beak to fish out larvae in tree cavities. Darwin proposed that the Galapagos finches evolved on the islands from a single species of finch from mainland South America. Modern methods of DNA (genetic) analysis have confirmed his insight. Darwin's finches are classified in three genera of the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Fringillidae, subfamily Geospizinae. Can you spot the difference? Discuss. What might they have been used for? Discuss. 13 13

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Rufous hummingbird (Selasphorus rufus) Rufous hummingbird (Selasphorus rufus). A hummingbird's long bill and tongue evolved to let the bird reach deep into a flower for nectar. 15 15

Homologous Structures Look at the pictures. What do you think ‘homologous’ means? 16

What might you infer from these homologous structures? 17

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Ida goes way back to 47mya 19 19

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Brain sizes 22 22

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Australopithecus 3.9 – 3mya 24

Australopithecus 3.9 – 3mya 25

Lucy Ape like skull. Human –like pelvis and femur for walking upright. 26

Ida 27

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Monkey Darwin The Hornet, 1857 29

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