Evidence for Evolution (bio - unit 2)

fossil record and biogeography

remains or traces of organisms from the past, usually found in sedimentary rock, which appears in layers of strata

darwin noticed that ____ often resembled living species from the same region

using paleontology - transitional fossils show change through time. Species resemble nearby species.

comparative embryology

early stages look similar. same blueprint, different outcomes. embryos start alike, then develop into different species

anatomical homologies

some features shared between species make little sense except in the context of evolution

homologous structures are anatomical resemblances that represent variations on a structural theme present in a common ancestor

similar structure different functions. some parts are leftover from earlier designs (vestigial structures)

DNA and molecular homologies

m____ h_____ are shared genes inherited from a common ancestor

homologous genes and their products can be found in organisms as dissimilar as humans and bacteria

many organisms have retained genes that, like vestigial structures, have lost their function 

all life uses DNA, RNA, and the same genetic code to build proteins

(subcategory) biogeography

the study of the geographic distribution of species

pangea —> continental drift

continental movement and modern distribution of species helps us predict when and where different groups evolved

islands resemble the nearest mainland (law of succession)

(subcategory) paleontology

the study of fossils. (georges cuvier) noted that fossils in older strata were more dissimilar to to modern forms

(subcategory) vestigial structures

organisms sometimes contain features that served important functions in an ancestor but serve no current purpose