Evolution and Classification summary sheets.

Classification
All living organisms can be classified into 5 kingdoms
"Before the nucleus" DNA in
Cytoplasm. E.g. Bacteria + cyanobacteria
Usually unicellular eukaryotes.
E.g. Slime, mould, algae.
Consist of Mycelium (hyphae strands). Chitin
cell walls. Eukaryotic. Multinucleate.
Plants. Eukaryotic. Multicellular. Cellulose
Cell wall. Large amount of mitochondria
Multicellular. Eukaryote. Usually motile.
The kingdom is decided under the following classifications
Phylum Class Order Family Genus Species
Please Cool Off For Goodness Sake
Keys are used to identify living organisms. E.g. The Dichotomous key ­ which asks a series
of questions where there should ONLY be YES or NO answers.
Genus species
Modern Classification
Still use Observable features. But also Molecular Evidence.
Eg. Physiology, Biochemistry, Genetics, Protein Analysis, DNA and RNA Sequencing.
1970's. Carl Woese. RNA could be compared/analysed by computer easily.
Lead to separation of the prokaryote group. Total of 3 Domains
Eubacteria Archaebacteria Eukaryote
Cellular Prokaryotic Prokaryotic Eukaryotic
organisation
Cell wall (if Peptidoglycan (murein) Do not have peptidoglycan Do not have peptidoglycan
present) Cellulose (plants)
Chitin (fungi)
Cell membrane Unbranched hydrocarbon, Branched hydrocarbon, ester- Unbranched hydrocarbon,
ester-linked to glycerol linked to glycerol ester-linked to glycerol
Antibiotic Insensitive to those that Sensitive to some that affect Insensitive to those that affect
sensitivity affect Eukaryotae Eubacteria and some that Eubacteria
affect Eukaryotes
ssrRNA Regions unique to Regions unique to Regions unique to Eukaryotae
Eubacteria Archaebacteria
Main groupings Gram positive and gram Extremophiles: Protoctista, Fungi, Plantae
negative bacteria Methanogens and Animalia
Cyanobacteria Extreme halophiles and
thermophiles…read more

Evolution
Continuous Variation Intermediates Present. Character controlled by many
genes.. Usually affected by environment.
Discontinuous Variation Few/No Intermediates. Generally controlled by single gene.
Inter-specific Variation Difference between species [Basis of classification]. Morphology,
physiology, behaviour, genetics.
Intra-specific Variation Within a species. E.g. Dogs
Meiosis Shuffles Alleles so gametes contain a random mixture.
Sexual Reproduction Male gametes fuse randomly with female gametes. Alleles from different
individuals are combined in zygote.
Mutation Mistakes in DNA replication. E.g. Different base code changing the amino
acid type in a protein.
Environmental Affect characteristics of organism. E.g. UV exposure darkens skin.
Evidence: Fossils - Change over geographical time scale, DNA- Base sequences, Molecular- Amino Acid sequences
Adaptation
Behavioural E.g. Avoiding hottest time of day, Sentry Duty to evade predators. Escape
reflexes.
Physiological Correct/Appropriate functioning E.g. opening/closing stomata in response to
CO2, light, humidity/water stress.
Anatomical/Structural Blubber- Insulation. Large Ears in Elephants = Cooling. Long roots in
xerophytes = greater water source.
Natural Selection
Darwin's Observations
Able to produce large numbers of Dogs ­ 10 pups. Cod- 250,000- 500,000 eggs. Mushroom ­ millions
offspring of spores.
Populations stay constant over Competition for survival - otherwise populations would rapidly
time. increase.
Offspring similar to parents. Offspring inherit some characteristics from their parents.
Variations exists within population. Some are better adapted to the environment than others. More likely
to survive and pass on characteristic to offspring. Survival of the
fittest.
Predation. Grazing.
Food Availability. Disease.
Physical/Chemical Factors
Speciation
Allopatric Populations are
physically separated by a
geographical barrier. E.g.
Mountains.
Sympatric Populations not physically
separated. Reproductive
barrier ­ often
physiological, behavioural
or genetic.…read more