cell evolution Flashcards
phylogeny
the evolutionary history of a species or group of species
phylogenies show evolutionary relationships
differences between prokaryotic and eukaryotic cells
Location of DNA –
- in eukaryotic cells DNA is in the nucleus enclosed in a plasma membrane
- in prokaryotic cells it is concentrated in a region that is not membrane enclosed called a nucleoid
Type of DNA
- Eukaryotes have linear DNA / prokaryotes have circular single stranded DNA
Organelles
- eukaryotic cells have membrane bound organelles
- prokaryotic cells do not have membrane bound organelles (though prokaryotic cells have regions surrounded by proteins
Size
- Eukaryotic cells are generally bigger
differences between prokaryotic and eukaryotic cells
Location of DNA –
- in eukaryotic cells DNA is in the nucleus enclosed in a plasma membrane
- in prokaryotic cells it is concentrated in a region that is not membrane enclosed called a nucleoid
Type of DNA
- Eukaryotes have linear DNA / prokaryotes have circular single stranded DNA
Organelles
- eukaryotic cells have membrane bound organelles
- prokaryotic cells do not have membrane bound organelles (though prokaryotic cells have regions surrounded by proteins
Size
- Eukaryotic cells are generally bigger
how are eukaryotic and prokaryotic cells similar
Bounded by plasma membrane
Contain cytosol
Contains chromosomes
Contain ribosomes
taxonomy
how organisms are named and classified
binomial system of naming species
Linnaeus first part of the name is the genus second part is the specific name - unique to each species within the genus Genus has capital letter should be italics and latinised
Linnaean classification system
species, genus, family, order, class, phylum, kingdoms , domains
“Dear King Philip Came Over For Good Soup”
taxon
the named taxonic unit at any level
e.g. homo sapiens has two taxons
phylogenetic tree
evolutionary history of a group of organisms represented in a branching diagram
branch point
represents the common ancestor of the two evolutionary lineages diverging from it
sister taxa
groups of organisms that share the same immediate common ancestor that is not shared by any other group
the members of a sister group are each other’s closest relatives
what defines a species
can reproduce to produce viable offspring
how did Whittaker classify living things
5 kingdom classification
monera (prokaryotes) protista (small eukaryotes) plantae fungi animala
how did Woese classify living things
Molecular approach - to define the different types of life
use of DNA to distinguish / the more related the DNA the more related the organisms
Prokaryotes - Bacteria and Archaea
Eukaryotes - plants, fungi, animals, protists
homologies
phenotypic (appearance) and genetic similarities due to shared ancestry
convergent evolution
when similar environmental pressures and natural selection produce similar (analogous) adaptations in organisms from different evolutionary lineages e.g. two animals that look similar but have different internal anatomy etc.
e.g. an echidnas quills and a cactus’s spines
clade
a group which includes an ancestral species and all of its descendants e.g. diprotodontia includes kangaroos and wombats
what was needed on earth for the first life to appear
small molecules
abiotic synthesis of small organic molecules
joining of these small molecules into macromolecules such as proteins and amino acids
the packaging of these molecules into protocells
the origin of self replicating molecules
when did our planet form
4.6 billion years ago
what was the Miller Urey experiment
created lab condition similar to those on Earth 4 billion years ago
showed that the Earth’s atmosphere was reducing environment in which organic compounds could have formed from simpler molecules
Miller produced amino acids
more recent theories about where first organic molecules appeared
near volcanoes / hydrothermal vents - alkaline vents
meteorites
protocell
droplets with membranes that maintained an internal chemistry different to their surroundings
vesicles formed when lipids or other organic molecules are added to water
vesicles can divide on their own
