HEXAPODS AND ANGIOSPERMS
INSECT EVOLUTION: HEXAPODS AND ANGIOSPERMS Most modern families radiated (50%+)
Most modern orders First winged insects First hexapods PANGAEA Cretaceous-Tertiary Extinction Gnetales - Ancestors of Angiosperms? Fossil Pollen Animal Pollination Advantages 1. Precision of transfer 2. Gene flow 3. Reproduction in sparse populations 4. Speciation Orchid Pollination Fossil Evidence for Insect Pollination
1. Pollen in guts of fossilized insects 2. Structure of flowers 3. Specialized insect structures Fossil Evidence for Insect Pollination
1. Pollen in guts of fossilized insects 2. Structure of flowers 3. Specialized insect structures Fossil Evidence for Insect Pollination
1. Pollen in guts of fossilized insects 2. Structure of flowers 3. Specialized insect structures 4. Ability to hover Orchids and Hawkmoths (Lepidoptera: Sphingidae) Orchids and Hawkmoths (Lepidoptera: Sphingidae)
Anther cap Orchids and Hawkmoths (Lepidoptera: Sphingidae)
nectary Red Queen Hypothesis "Well, in our country," said Alice, still panting a little, "you'd generally get to somewhere else if you run very fast for a long time, as we've been doing." "A slow sort of country!" said the Queen. "Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!" For an evolutionary system, continuing change is needed just so that one species can maintain its fitness relative to the species with whichit is co-evolving. Orchid lengthens nectary to draw moth closer to pollen
Orchids and Hawkmoths (Lepidoptera: Sphingidae) Moth lengthens proboscis to reach nectar Orchid lengthens nectary to draw moth closer to pollen Figs and Fig Wasps Pleistodontes froggatti Figs and Fig Wasps Ficus macrophylla Figs and Fig Wasps Figs and Fig Wasps