Biology- 4.3 Classification and Evolution

Placing living things into groups. For convenience, makes study more manageable, easier to identify organisms and helps us to see relationships between species.
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Studying differences between different species, in order to classify.
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8 Taxonomic Levels
Domain. Kingdom. Phylum. Class. Order. Family. Genus. Species.
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How closely related 2 different species are. Phlogenetic trees help us see how closely 2 organisms are evolutionary linked, closely related species diverge more recently.
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Binomial Naming System
Uses genus name and species name to avoid confusion when naming animals. Uses Latin as universal language. Carl Linnaeus.
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Standard Deviation
Measure of how spread about the data is around the mean. Low= data has narrow range= greater reliability. X= individual value. X-= mean. n= no. data points.
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Student's t-Test
Used to compare 2 different means to see if there is a significant difference between sets of data. X-1= mean from 1st set of data. S1^2= standard deviation from 1st set of data squared. n1= no. data points.
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Spearman Rank Correlation Coefficient
How 2 sets of data are related. Closer to 0= weaker correlation. Closer to +1, stronger positive correlation (1=perfect correlation). Closer to -1= stronger negative correlation. D= difference between ranks. n= no. pairs of values.
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Phylogenetic Definition of Species
Group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics,
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5 kingdoms
Prokaryote (eg. bacteria, no nucleus, parasitic). Protoctista (eg. paramecium, eukaryotic, plant and animal like). Fungi (eukaryotic, chitin cell walls, saprophytic). Plantae (euakaryotic, autotrophic). Animalia (eukaryotic, heterotrophic).
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Evidence Used in Classification
Courtship behaviour. Observable features (convergent evolution= issue). Biological molecules- cytochrome c= protein used in respiration, amino acid sequence compared. Genome (DNA base) sequencing- compare genetic codes.
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3 Domain Classification
Woese. Divided prokaryote kingdom into bacteria and archaea, because archaea are more similar to animals because have similar enzymes (RNA polymerase) for DNA synthesis, have similar DNA replication mechanisms and produce proteins that bind to DNA.
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Artificial Classification
Based on few characteristics, doesn't reflect evolutionary relationships, limited info, stable.
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Natural Classification
Detailed study of individuals in species. Uses many characteristics, reflects evolutionary relationships, lots of useful info, may change with advancing knowledge.
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Natural Selection
Features of environment apply selective pressure on reproduction of individuals in population. Mutation creates variation (alleles). Selective pressure. Individuals w/ advantageous characteristics survive and reproduce, passing along alleles.
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Which 2 scientists independently proposed the mechanism (natural selection) for the process of evolution?
Darwin and Wallace
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Evidence for Evolution
Fossils- moderns species similar to old species have variations meaning better suited to habitat. Biological molecules- certain molecules found in all living world suggest all species arose from 1 common ancestor. DNA (genome) sequencing comparisons.
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Differences between individuals,
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Intraspecific Variation
Differences between members of same species.
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Interspecific Variation
Differences between species.
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Continuous Variation
2 extremes and full range of intermediate values in between. Often regulated by more than 1 gene can be affected by environment.
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Discontinuous Variation
Distinct categories and no intermediate values in between. Usually regulated by 1 gene and not affected by environment.
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Genetic Variation
Caused by possessing different combination of alleles.
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Environmental Variation
Caused by response to environmental factors,
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Characteristic that enhances survival in habitat. Helps organisms cope w/ envrionmental stress and obtain things needed for survival.
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Anatomical Adaptation
Structural features. eg. Marram grass (xerophyte) has long roots and thick waxy cuticle.
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Behavioural Adaptation
Ways behaviour is modified for survival. eg. Marram grass responds to shortage of water by rolling leaf and closing stomata.
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Physiological/ Biochemical Adaptations
Ensures correct functioning of cell processing. eg. Marram grass- guard cells open and close based on cell turgidity and maintain low cell water potential to ensure survival in salty conditions.
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Convergent Evolution
2 unrelated species living in similar habitats evolve to have similar adaptations. eg. Marsupial mole and placental mole have cylindrical body, small eyes and strong front legs.
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How have insects developed resistance to insecticides?
Applies strong selection pressure, some resistant individuals (due to mutations) survive, reproduce and pass on resistant characteristics/alleles.
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How have bacteria developed resistance to antibiotics?
Applies strong selection pressure, some resistant individuals (due to mutations) survive, reproduce and pass on resistant characteristics/alleles. eg. MRSA.
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Studying differences between different species, in order to classify.

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8 Taxonomic Levels


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Binomial Naming System


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