Chapter 2 Flashcards
(27 cards)
Repeated paired structures- may be homologous as a group between species, but not as individual elements
Serial homology
Two structures that have the same functions in different species but are not homologues (coincidental resemblances)
Analogues
Evolutionary history
Primary goal of systematics
Phylogeny
How is a phylogeny represented?
Cladogram
Change from a preexisting ancestral condition to a new derived condition
Evolution
Derived condition that represents evolutionary novelty
Apomorphy
Apomorphy that unites 2 or more lineages
Synamorphy
Branching of cladogram represents lineage _________
Divergence
Point of divergence of one clade into two, where the most recent common ancestor of the two divergent clades is located is called
Node
Non molecular features like organ morphology, anatomy, embryology, palynology, reproductive bio
Morphological characters
Phylogenetic analysis derived from genetic data such as DNA sequences
Molecular character
Structures in 2 different species that arise from same embryonic precursor
Homologues
Nonhomologous similarities
Homoplasy
Metamerism may be homologous as a group between species, but not as individual elements
Our ribs match sharks but not the same from rib to rib
Serial homology
Two structures that have the same functions in different species but are not homologues (coincidental)
Analogues
Hereditary modification of a phenotype that increase the probability of survival due to selected mutational changes in genotype
Biological adaptation
Already existing traits or structures that enable a phenotype to meet a new environmental challenge before it materializes
Preadaptation
Formation of new species that results in inability to interbreed and is driven by genetic drift
Speciation
When 2 or more unrelated species occupy the same environment (can be concurrent or millions of years apart) develop similar adaptive morphological trait
Evolutionary covergence
Features common to all members of a major taxonomic group develop earlier in ontogeny than do special features that distinguish subdivisions of the group
Von Bauer’s Law
Delevopmental history of an individual organism, embryo to death
Primary operant=genes
Ontogeny
Evolutionary history of a taxon (group, species, family)
Primary operant= speciation
Phylogeny
Better consideration of von bauer’s law
Features that develop earliest in ontogeny are the oldest phylogenetically, features that develop later are more recent phylogenetic origin
Biogenetic law
Practice of ordering organisms into hierarchies (taxa) based on preselected criteria (morphological or molecular) and thereby yields classification
Systematics
