10 - Classification and Evolution Flashcards
What is the order of classification? (i.e. class, genus etc. in order)
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
What is the name of the groups of classification (i.e. class, genus etc.)?
Taxonomic groups
What were the traditional 5 kingdoms?
Animalia, Fungi, Protoctista, Plantae, Prokaryotae
Who was the first to propose a modern system of classification and when?
Carl Linnaeus in the 18th century, hence it being named Linnaen Classification
What is the binomial naming system?
Where we use the Genus and Species names (in that order) to identify a species
What is an advantage of using the binomial naming system?
It removes the language barrier between two scientists without a common language who wish to talk about the same organism
Can organisms in the same genus reproduce?
Yes, but they only produce infertile offspring
What is the infertile offspring of two organisms of the same genus called?
A hybrid, and has no Latin name
When was the 6-kingdom model of classification with domains first introduced and by whom?
1977 by Carl Woese
What are 3 reasons that scientists classify organisms?
- To identify species 2. To predict characteristics 3. To find evolutionary links
What is one slight limitation of using a classification system?
The classification is created by humans instead of being defined by nature
What are some features of organisms from the Animalia kingdom?
Multicellular, heterotrophic feeders, no chlorophyll, no cell wall, complex cell structure with nucleus
What are some features of organisms from the Plantae kingdom?
Multicellular, cellulose cell wall, autotrophic feeders using chlorophyll, complex cell structure with nucleus
What are some features of organisms from the Fungi kingdom?
Multicellular, cell walls not made of cellulose, saprophytic feeders so no chlorophyll, complex cell structure with nucleus
What are some features of organisms from the Protoctista kingdom?
Mostly unicellular (a few multicellular), complex cell structure with nucleus
What are the 3 domains?
Eukaryotes, Eubacteria, Archebacteria
Why are some hybrids infertile?
Because they have an odd number of chromosomes
What are some features of Eukarya?
Eukaryotic, bilipid cell membrane, membrane-bound organelles, contain 80S ribosomes, RNA Polymerase has 12 proteins
What are some features of Archaea?
Prokaryotic, monolipid cell membrane, no true organelles, extremophiles, 70S ribosomes, RNA Polymerase has 8-10 proteins
What cellular feature makes Archaea such good extremophiles?
Their monolipid cell membrane is very resistant to being disrupted
What are the main differences between Archaea and Eubacteria?
- Archaea have no peptidoglycan in their cell wall 2. Different number of proteins in RNA Polymerase 3. Archaea have a monolipid cell membrane, Eubacteria have a bilipid cell membrane 4. Eubacteria are found in all environments whereas Archaea tend to be extremophiles
What are some features of Eubacteria?
Prokarotic, peptidoglycan cell wall, no true organelles, 70S ribosomes, RNA Polymerase contains 5 proteins
Why do scientists think Archaea were some of the earliest life?
They were extermophiles, and conditions on early Earth were very hostile
Are Archaea or Eubacteria more common?
Eubacteria
What is a protein which indicates a shared ancestry between primates?
Haemoglobin- there is only 1 amino acid different between humans and chimpanzees
Where do methanogens live and what do they do?
They live in anaerobic environments such as sewage treatment plants, and make methane
What are some examples of places that extremophilic Archaea live?
Anaerobic conditions, highly acidic environments and hot thermal vents
What does a phylogenetic tree do?
Help us see relationships between organisms and common ancestors
What does it mean when a branch on a phylogenetic tree does not make it to the top of the diagram (i.e. the modern day)?
That the species is extinct
What causes variation within a species?
Random genetic mutations
What is interspecific variation?
Variation which occurs between different species
What is intraspecific variation?
Variation which occurs within a species
What is continuous variation?
Variation which can take any value in a given range
What is discontinuous variation?
Variation which can only take certain values within a given range
How do DNA mutations cause variation?
They can lead do different proteins being coded for, which would give rise to different proteins
What are the 3 genetic causes of variation?
- Sexual reproduction mixing alleles from the two individuals’ gametes 2. Which alleles the gametes contain is down to chance during meiosis (assortment and crossing over) 3. Mutations to the DNA sequence
What is phylogeny?
The evolutionary relationships between organisms
What is phylogenetics?
The study of the evolutionary relationships between organisms
What does the closeness of the branches of a phylogenetic tree mean?
The closer the branches, the more closely related the organisms are
How can classification use phylogeny?
To confirm that classification groups are correct, or that they need to be changed
What are two advantages of phylogeny over classification?
- Phylogeny allows production of a continuous tree instead of placing organisms into discrete groups like classification 2. Hierarchical nature of classification can be misleading as it implies, for example, that the orchid and cat families are equal, even though there are 35 cat species and 30,000 orchid species. Phylogeny clarifies this.
What shape is a normal distribution?
A ‘bell curve’