Lecture 1 Flashcards
What are some ways organisms can be related to one another?
They can be related through an ancestor or through existing in similar conditions.
Define Phylogeny
The evolutionary history of a species or a group of related species.
The discipline of _____ classifies organisms and determines their evolutionary relationships.
Systematics
What does the discipline of systematics do?
It classifies organisms and determines their evolutionary relationships.
What type of information do systematists use to infer evolutionary relationships?
Fossil, Molecular, and Genetic Data. FMG
Which scientist was responsible for taxonomy?
Carl Linnaeus
What does the two part name of an organism consist of and what are the rules?
It comes in the order of genus then species. Genus is always capitalized whilst species is always in lowercase.
How do systematists depict evolutionary relationships?
They do so in branching phylogenetic trees.
What does a phylogenetic tree represent?
It represents a hypothesis about evolutionary relationships.
Define Branch Point
A branch point is a point on the phylogenetic tree that represents the divergence of 2 species.
Define Sister Taxa
They are groups that share an immediate common ancestor.
What is a polytomy representing?
Its representing an unsolved pattern of divergence.
What is found with organisms with similar DNA sequences ?
They have been found to be related more closely compared to organisms with different structures or sequences.
Define Homology
Similarity due to shared ancestry. HA
Define Analogy
Similarity due to convergent evolution. Convergent evolution occurs when similar environmental pressures and natural selection produces similar (analogous) adaptations in organisms from different evolutionary lineages.
What is a way of distinguishing between homology and analogy?
By comparing fossil evidence and degree of complexity.
What are some indications that two organisms are homologous?
If the genes in two organisms share many portions of nucleotide sequence, it is likely that they are homologous. If they have more elements that are similar, the more likely it is that they are homologous.
Define Cladistics
A practice that involves grouping organisms by common descent.
Define Clade
A group of species that includes an ancestral species and all of its descendants.
Do all groupings of organisms form a clade?
No, they do not.
What are the different types of scenarios that can happen in cladistics?
Monophyletic-Paraphyletic-Polyphyletic
Define Monophyletic
A monophyletic clade is a valid clade, signifying that it consists of the ancestor species and all of its descendants.
Define Paraphyletic Clade
A group that consist of an aces trail species and some, but not all, of the descendants.
Define Polyphyletic Clade
Grouping includes distantly related species but does not include their most recent common ancestor.
