Table 11.1 Flashcards
The most logical and useful system groups organisms hierarchically.
Biological classification
Humans appear most similar to the great apes
Biological classification
All species in the same family share a relatively recent common ancestor, and all families in the same class share a more distant common ancestor
Biological classification
Organisms that look quite different have surprisingly similar structures
Anatomical homology
Mammalian forelimbs share a common set of bones organized in the same way, despite their very different functions.
Anatomical homology
The simplest explanation is that each species inherited the basic structure from the same common ancestor, and evolution led to their modification in each group.
Anatomical homology
Some species display traits that are nonfunctional but have a functional equivalent in other species
Vestigial traits
Flightless birds such as ostriches produce functionless wings
Vestigial traits
The simplest explanation is that the trait was functional in an ancestral species but lost its function over time in one branch of the evolutionary tree
Vestigial traits
The distribution of organisms on Earth corresponds in part to the relationship implied by biological classification
Biogeography
The different species of tortoises on the Galapagos islands are clearly related
Biogeography
Similarities among species in a geographic location imply divergence from ancestors in that geographic location
Biogeography
Early embryos of different species often look similar
Homology in development
All chordates- animals that have a backbone or closely related structure produce structures called pharyngeal slits, and most have tails as early embryos.
Homology in development
Similarities in early development suggest that these organisms derived form a single common ancestor that developed along a similar pathway
Homology in development
The DNA sequences of species that are closely related in a taxonomic grouping are more similar than those from more distantly related groups
Homology of DNA
Animals in the same genus have more similar DNA sequences than animals in different genera but the same family.
Homology of DNA
Similar DNA sequences in different species imply that the species evolved from a cannon ancestor with a particular sequence
Homology of DNA
The remains of extinct organisms show progression from more ancient forms to more modern forms.
The fossil record
The transition between ancient and modern horses
The fossil record
Fossils provide direct evidence of change in organisms over time and suggest relationships among modern species.
The fossil record
