BIOLOGY 1B Lecture Notes - Lecture 22: Trophic Cascade, Osprey, Abiogenesis
Document Summary
Ecosystems are a level in the hierarchy (like guilds, communities, etc. ) Ecosystem is an approach to studying organisms, not necessarily higher than communities. Origin of life = origin of ecosystems. Literature has insights on realities of food chains. Darwin was relying on others o(cid:271)ser(cid:448)atio(cid:374)s a(cid:374)d his said that (cid:271)ees polli(cid:374)ate (cid:272)lo(cid:448)er. If there are no cats, then there are alot of mice, that would make the bees disappear, and make flowers disappear. This food interpretation is a connected system. Earliest pu(cid:271)lished food (cid:272)hai(cid:374) shri(cid:373)p at (cid:271)ase, the(cid:374) osprey at top, (cid:449)ith i(cid:374)(cid:272)reasi(cid:374)gly growing fish going up to osprey. Causality going up is easy to explain; at the base, is the physical environment (abiotic - nonliving space); changes in abiotic realm influences vegetative (autotrophic realm); this propogrates up to the rest of the food chain (bottom-up causality) Top-down causality: more of what darwin was saying. Levels of food chains: autotrophs, primary consumers, secondary consumers, tertiary consumers, quaternary, etc .
