Lecture Two: Evolution, Phylogenies, Characteristics Flashcards
January 28
What makes up the VAST majority of animal life?
Invertebrates.
At its simplest, what makes a vertebrate a vertebrate?
The presence of vertebrae.
What is the first vertebrate?
Lamprey.
Why are hagfish not vertebrates?
No living hagfish have vertebrate.
Though, they have the genetic material to make vertebrate so it is possible their ancestors may have had them.
Is evolution a direct process?
No, it is random. Mutation occur in an organism that may or may not be advantageous to its environment.
Monophyletic:
Ancestor and ALL descendants.
Paraphyletic:
Polyphyletic:
Outgroup:
Shares certain similarities to the main group being spoken of, but just different to sit outside.
Ex. If vertebrates are the “in-group,” hagfish would be an outgroup since they are craniates and chordates, but not vertebrates.
Shared Ancestral Characteristic:
Trait found in ancestor and not descendant.
Shared Derived Characteristic:
Trait only found in descendants and not the ancestor. Differentiates descendant from ancestor.
Homologous:
Same components (ex. bat wing and human hand).
Analogous:
Same function, not necessarily same components (ex. fish and whale caudal fin).
Convergent Evolution:
Appearance of a functional trait that appears in distantly related groups (ex. whale and fish tail).
(For this class… would be across groups like fish and mammals)
Parallel Evolution:
Appearance of the same functional trait in relatively closely related groups
(For this class… would be in the same group such as mammals.)
HOX genes:
Cluster of genes that lay out a specific body plan for organisms.
Usually, HOX genes are associated with what?
Increased complication in body plans.
When did one cluster of HOX genes arise?
Invertebrates, chordates.
When did two clusters of HOX genes arise?
Craniates.
(Distinct head)
When did four clusters of HOX genes arise?
Gnathostomes.
(Jaws and faired appendages)
What type of character would an organism have at its first appearance? After its first appearance (with descendants)?
Shared derived.
Shared ancestral.
What traits are unique to vertebrates that have not already appeared in invertebrates?
Vertebrae.
Skin, scales, feathers, mammary glands.
Why are there so few unique traits to vertebrates compared to invertebrates?
Invertebrates have been around MUCH longer than vertebrates.
They have had much more time to develop nervous systems, complex social structures, distinct heads, complex brains, and so on.
What are the levels of Linnean classification from least to most specific?
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
