BIOLOGY GRADE 11 NOTES Essay

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Biology Grade 11 Exam Study Guide
Diversity
Taxonomic Categories
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Hierarchy
From most general to most specific

Binomial Nomenclature
System used to identify all organisms on Earth
Identifies an organism by its genus and species (ex. Humans-homo sapiens)
Developed by Linnaeus in the 18th century

Identifying Species
3 methods:
Morphology
 Form and shape
 It is simple but there are natural variations in population
Biology
 If species are able to have sex and produce viable offspring
 It is widely used however cannot always be used due to geographic separation, asexual reproduction and extinction of fossils
Phylogeny
 Evolutionary relationships
 Can

Giraffes with long necks
Disruptive Selection
 Occurs when selection favours the extreme variation over the intermediate
 Seed cracker finch
 Can lead to speciation
Directional selection
 Occurs when selection favours one particular variation
 Ex. Peppered moth
Sexual Selection
 Selects for an organism’s ability to obtain a mate and reproduce
 Can create structures and behaviours that are harmful to an individuals’ survival
 Ex. Peacock tail: attracts females but predators too
 Intrasexual
Competition with one sex: attention of females,