IB biology A3.2.1 classification of organisms; A3.1.3 Binomial system for naming organisms; A3.1.14 Engagement with local plant or animal species to develop a dichotomous key; A3.1.1 Variation between organisms as a defining feature of life; D3.2.15 Box-and-whisker plots to represent data for a continuous variable such as student height.

Taxonomy

This branch of biology focuses on classifying living things.

Taxonomic levels

Domain, Eukarya, Phylum, Class, Order, Family, Genus, Species

Binomial Nomenclature

2 terms used to denote the species:

• the first term indicates the genus 

• the second term indicates the specific species

Dichotomous key

A tool used to identify a species (A3.1.2) based on observable traits. 

Variation

Differences between members of a group. Can be discrete or continuous.

Discrete variation

Traits that can be put into distinct qualitative categories. This is usually influenced by only one or a few genes. They can also be influenced by environment, although usually not significantly. (ex:Hand used for writing (left or right))

Continuous variation

Traits that vary along a quantitative continuum. (most types of biological variation is this type). This is the result from complex interaction between many different genes (“polygenic”), often with the environment playing a significant part in the expression of the phenotype. (ex:Height (wide range of values, eg 1.69m))

Intraspecies variation

Variation within a species. (obv)

Intraspecies genetic variation can be from:

Mutation, gene flow, meiosis, sexual reproduction

Natural selection is…

…the main force that drives evolution

Differential survival and reproduction is…

…a part of natural selection.

Discrete quantitative data

a finite value that can be counted

Continuous quantitative data

an infinite number of possible values can be measured

Gene flow

the spatial movement of genes, typically through seed and pollen dispersal, either within a population or between separated stands

Meiosis

a type of cell division during which a single cell divides twice and produces four daughter cells