Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The Binomial System: Species are identified by a two-part name consisting of the (capitalized) and (lowercase), both written in italics or underlined, such as .
Hierarchy of Taxa: Organisms are classified into a hierarchy of taxa: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species. A mnemonic is 'Dear King Philip Came Over For Good Soup'.
The Three Domains: All organisms are classified into three domains: (extremophiles), (true bacteria), and (organisms with a membrane-bound nucleus).
Plant Phyla: Major phyla include (no vascular tissue, e.g., mosses), (vascular, spores, e.g., ferns), (seeds in cones, e.g., pines), and (flowers and fruits).
Animal Phyla: Key invertebrate phyla include (no symmetry, pores), (radial symmetry, stinging cells), (bilateral, flat, no heart), (segmented, bilateral), (mantle, muscular foot), and (exoskeleton, jointed appendages).
Chordata: A phylum characterized by having a notochord at some stage of development. Includes sub-classes like , , (birds), and .
Natural Classification: Groups together species that share a common ancestor. This allows for the prediction of characteristics within a group and helps in the identification of new species.
Reclassification: Taxonomists may reclassify groups of species when new evidence (often molecular, such as sequences) suggests a different evolutionary pathway.
📐Formulae
💡Examples
Problem 1:
Calculate the Simpson's Diversity Index () for a sample containing three species: Species A (), Species B (), and Species C ().
Solution:
Explanation:
Simpson's Diversity Index measures the probability that two individuals randomly selected from a sample will belong to the same species. A higher value usually indicates greater biodiversity.
Problem 2:
Identify the plant phylum: A plant has vascular tissue, does not produce flowers, and reproduces via seeds found in woody cones.
Solution:
Explanation:
The presence of vascular tissue eliminates . The use of seeds rather than spores eliminates . The presence of cones and lack of flowers identifies it as .
Problem 3:
Two species show a difference in their sequences. If the estimated mutation rate () is per million years, calculate the time () since they shared a common ancestor.
Solution:
Explanation:
Using the molecular clock hypothesis, the divergence time is calculated by dividing the total divergence by twice the mutation rate (to account for mutations accumulating in both lineages).