Lecture 2: Classifying life and reconstructing phylogenies Flashcards
Taxonomical hierarchy:
Kingdom Phylum Class Order Family Genus Species (King Philip Came Over For Good Spaghetti)
How do you write the genus and species name
UNDERLINE (+ italics)
Genus (capital) species (lower case )
Phylogeny:
Development or evolution of a particular group of organisms
What does PHYLOGENY have but TAXONOMY not have
TIME
What happened in the 1970’s?
there was a revolution giving us phylogenetic or cladistic analysis
Analogous:
Similarity due to convergent evolution (homoplasy) For example, the wings of a fly, a moth, and a bird are analogous because they developed independently as adaptations to a common function—flying.
Homoplasy:
a character shared by a set of species but not present in their common ancestor
Homologous:
Similarity due to common ancestry. examples of homologous structures are the bones in the forelimbs of various vertebrates, such as humans, dogs, birds and whales- from one LUCA, all used for different things
symplesiomorphies:
shared ancestral characters
synapomorphies:
shared derived characters
Autapomorphies:
characters unique to a taxon
Monophyletic group:
contains the latest common ancestor plus all, and only all, of its descendants (full branching from one common ancestor)
Paraphyletic group:
diagnosed by plesiomorphies & not including all the descendants of a common ancestor. A paraphyletic group remains after one or more parts of a monophyletic group have been removed. (just a section on a monophyletic diagram)
Polyphyletic group:
A group in which the most recent common ancestor is assigned to some either group itself. It is defined on the basis of convergence, or by non-homologous characters assumed to have been absent in the latest common ancestor. (2 separate branches from 2 bases with branches)
The classification on life
started as 5, now 3.
- Domain Bacteria
- Domain Eukarya
- Domain Archaea
Prok vs euk:
Organisms represent:
p = bacteria & cyanobacteria e = Protists, fungi, plants, animals
Prok vs euk:
Cell size:
p = generally 1-10 micrometers e = generally 10-100 micrometers
Prok vs euk:
Cellular organisation:
p = unicellular / colonial e = mainly multicellular with tissues and organs
Prok vs euk: cell walls:
p = made of particular sugars and peptides e = made of cellulose or chitin (but lacking in animals)
Prok vs euk:
Flagella & cilia:
p = some have flagella (but made of flagella protein) e = Flagella or cilia with micro tubules
Prok vs euk:
Organelles:
p = no membrane-bound organelles e = membrane-bound chloroplasts and mitochondria
Prok vs euk: metabolism & photosynthesis:
p = anaerobic, facultative aerobic e = aerobic
Prok vs euk:
Genetic organisation:
p = loop of DNA in cytoplasm e = DNA in chromosomes in membrane-bound nucleus
Prok vs euk:
Reproduction:
p = by binary fission. Dominantly asexual but some parasexual e = by mitosis or meiosis. Dominantly sexual
It is thought that eukaryotic cells are made up of
Bacterial cells (act as their organelles)
When was it discovered that there are two types of prokaryotes and what are they
1980’s
- Eubacteria (bacteria)
- Archaebacteria (Archaea)
Archaebacteria vs Eubacteria
Archaebacteria are less numbers and diverse than Eubacteria & inhabit extreme environments
Archaebacteria extreme environments e.g.=
- Thermophiles (v hot)
- Halophiles (v salty)