BIO 370 Lecture Notes - Lecture 28: Invertebrate, Cryptogam, Ecological Niche
Using Phylogenetic Trees to Classify Life
Taxon – Your ook sas a tao is, … a group of related orgaiss…. This is a it loose.
Historically, a taxon is a group of organisms seen by a taxonomist to form a unit and be
somehow worthy of naming.
This often included subjective judgements as to the relative importance of a trait, or ecological
position.
An eclectic and subjective (not theory based) mix of evolutionary and ecological criteria
• Ofte ot groups defied lak of traits
– Invertebrata
– Cryptogams (plants without cones or flowers).
• Eologial ihe ad a i of has ad ot
– Fishes (vertebrates lacking four limbs, that had gills and swam).
• “oe hae groups.
– Aves, tetrapods with forelimbs as wings, feathers, beaks/bills.
– Angiosperms (multicellular plants with flowers).
Evolutionary Theory says that all life has a common history. Under this concept, there is an
objective reality that should exist regardless of human perception – a unique historical
relationship – monophyly.
For the rest of this course, when we refer to taxon (pl., taxa), or natural group, we mean a
presumed or hypothesized monophyletic group.
Determination of monophyly requires a rooted tree.
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Document Summary
Taxon your (cid:271)ook sa(cid:455)s a ta(cid:454)o(cid:374) is, (cid:862) a group of related orga(cid:374)is(cid:373)s . (cid:863) (cid:894)this is a (cid:271)it loose. (cid:895) Historically, a taxon is a group of organisms seen by a taxonomist to form a unit and be somehow worthy of naming. This often included subjective judgements as to the relative importance of a trait, or ecological position. An eclectic and subjective (not theory based) mix of evolutionary and ecological criteria: ofte(cid:374) (cid:862)(cid:374)ot(cid:863) groups defi(cid:374)ed (cid:271)(cid:455) la(cid:272)k of traits. Cryptogams (plants without cones or flowers): e(cid:272)ologi(cid:272)al (cid:374)i(cid:272)he a(cid:374)d a (cid:373)i(cid:454) of (cid:862)has(cid:863) a(cid:374)d (cid:862)(cid:374)ot(cid:863) Fishes (vertebrates lacking four limbs, that had gills and swam): o(cid:373)e (cid:862)ha(cid:448)e(cid:863) groups. Aves, tetrapods with forelimbs as wings, feathers, beaks/bills. Evolutionary theory says that all life has a common history. Under this concept, there is an objective reality that should exist regardless of human perception a unique historical relationship monophyly.
