BIOL 121 Lecture Notes - Lecture 41: Biodiversity Hotspot, George Gaylord Simpson, Atlantic Horseshoe Crab
Document Summary
March 24, 2017: major episodes of extinction did not, in the end, lead to decreased biodiversity, george gaylord simpson (american paleontologist) estimated that 99% of the species originating since the cambrian (544 mya) are extinct. Causes: climate, atmosphere, landmasses, floods, glaciation, volcanic eruptions, meteorite impacts (cid:862)living fossils(cid:863, an extant species that has survived major extinction events and has remain unchanged (e. g. , morphologically) over time, it is not possible to have a living fossil. The ter(cid:373) (cid:862)livi(cid:374)g fossil(cid:863: individuals of an extant (living) species that are morphologically like a species that is only known from fossils; that is, it appears to have no close living (cid:862)relatives(cid:863) [(cid:272)losely-related species, e. g. : atlantic horseshoe crab (limulus polyphemus: a marine (lives along shores) arthropod, survived morphologically unchanged since the. Triassic (230 mya: closes relative trilobite. Changes in biological diversity=(biodiversity) thru time & varies spatially: a measure of the variety of life.
