Macroevolution The result of repeated speciation events Evidences

 Macroevolution  The result of repeated speciation events  Evidences

Macroevolution The result of repeated speciation events Evidences From From

From From Comparative Anatomy the Fossil Record

Biochemistry Biogeography Macroevolution evidences from the field of comparative anatomy

Congruence of anatomical features Vestigial structures Homology Living intermediates

Von Baers Law Congruence of anatomical features Shared features of 2 species which are derived from common ancestry should

be numerous. If two species are not from a shared ancestry then there is no particular reason for them to share an abundance of anatomical features.

Vestigial Structures Anatomical features which serve no function, or are more of a liability than a help. Thought to be passed down from an ancestor in which

the feature served a beneficial purpose. Examples whale hipbones, eyes of blind cavefish, ear moving muscles of humans Homologous Structures

Anatomical features which have the same developmental origin, but have a variety of developmental outcomes. Example The limb bud of the vertebrate becomes bird wing, bat wing,

whale flipper, horse leg, and human arm. Living intermediates Any species or taxon which has anatomical features that are considered

similar to an ancestral group linking two dissimilar taxa. Examples Hemichordates have features linking echinoderms and chordates. Peripatus has features linking

annelids and arthropods. Von Baers Law features common to all members of major phylogenetic group of animals

develop earlier in ontogeny than do features that distinguish subdivisions of the group Evidences for macroevolution from

the field of paleontology Confirmation of fossil age Strata sequence Isotope dating Index fossils

Missing links Concept of superposition

Fossil Succession Volcanic events and dating rocks

Index fossils rock beds with similar fossils are assumed to be approximately from the same age. If the age of one bed is known the matching beds are assigned the same age until proven otherwise.

Missing links are extinct forms that share features from two separate phylogenetic lines. Evidences for macroevolution from the

field of biochemistry Proteins immunotaxonomy electrophoresis amino acid sequence

DNA DNA DNA hybridization nucleic acid sequence

Evidence for macroevolution from the field of biogeography Continental drift and phylogenetic lines Taxa and their geographic radiations Islands, refugia and speciation

Continental Separations Pangea (triassic,220my) Laurasia Gondwana (jurassic, 160my) N. America, Europe, Asia, S. America,

Antarctica, Australia, Africa, India (cretaceaous, 100my) New Land Bridges Berringea, DeGeer/Thule passages, panamanian connection, Middle Eastern

Radiation of Taxa Regions of endemism may show a greater variety of taxon subgroups via repeated speciation events.

Regions more distant from an endemic center often have fewer taxon subgroups present. Islands, refugia and speciation

Fragmented populations, located in refugia of suitable habitat or on islands, speciate and form recognizable subgroups.

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