How to write a scientific name correctly every time
Genus is always capitalized. Species is always lowercase. Both are italicized (or underlined in handwriting). Example: Homo sapiens.
🧬 Taxonomy
3 Domains: BEA
The Three Domains of Life
Bacteria, Eukarya, Archaea — the three domains
Bacteria: prokaryotes, no nucleus. Archaea: prokaryotes, extremophiles. Eukarya: all organisms with a nucleus (animals, plants, fungi, protists).
🧬 Taxonomy
"Fungi are not Plants"
Fungi Kingdom
Key features that separate Fungi from Plants
Fungi are heterotrophs (don't photosynthesize). Their cell walls are made of chitin, not cellulose. They absorb nutrients externally. Mushrooms, molds, and yeasts are all fungi.
🧬 Taxonomy
Shared features = more recently related
Reading Phylogenetic Trees
How to read a cladogram or phylogenetic tree
Species that share a node (branching point) are more closely related. The more recent the common ancestor, the more shared characteristics. Read from the root up.
Five Kingdom System
5 Kingdoms: MFPPA — Monera, Fungi, Protista, Plantae, Animalia
Five Kingdom System
The traditional five kingdoms of life — still tested widely
Vertebrate classes: Fish Amphibians Reptiles Birds Mammals — Foolish Animals Really Bug Me
Vertebrate Classes
Five vertebrate classes in evolutionary order
Fish (ectotherm, gills, scales). Amphibians (ectotherm, moist skin, both water and land). Reptiles (ectotherm, dry scales, fully terrestrial). Birds (endotherm, feathers, hollow bones). Mammals (endotherm, hair, mammary glands). Each class adapted to its environment.
F
Fish — gills, scales
A
Amphibians — moist skin, two worlds
R
Reptiles — dry scales, terrestrial
B
Birds — feathers, endotherm
M
Mammals — hair, mammary glands
Scientific Naming Rules
Binomial nomenclature: Genus species — Homo sapiens. Capital G, lowercase s, italicized.
Scientific Naming Rules
How to write a scientific name correctly — always the same format
Two-part Latin name: Genus (capitalized) + species (lowercase). Always italicized in print, underlined when handwritten. Examples: Homo sapiens, Canis lupus (wolf), Panthera leo (lion). The genus groups related species; the species name makes it unique.
Convergent vs Divergent Evolution
Convergent evolution: unrelated species develop similar features (shark + dolphin fins)
Convergent vs Divergent Evolution
Two very different evolutionary patterns — don't confuse them
Convergent: unrelated species independently evolve similar structures due to similar environments (shark fin + dolphin fin + ichthyosaur fin — all unrelated). Divergent: related species evolve different features (Darwin's finches). Analogy vs homology.
Reading Cladograms
Cladogram: the more branching points shared, the more closely related
Reading Cladograms
How to determine evolutionary relationships from a branching diagram
Each branching point (node) represents a common ancestor. Two organisms that share a more recent common ancestor are more closely related. Derived characters (new traits) appear at each node. Outgroup: the reference organism that branched off earliest.
Protista: diverse single-celled eukaryotes (amoeba, algae, slime molds). Fungi: absorptive heterotrophs with chitin cell walls. Animalia: ingestive heterotrophs, no cell walls. Plantae: photosynthetic autotrophs, cellulose cell walls. All four share the membrane-bound nucleus.
P
Protista
F
Fungi
A
Animalia
P
Plantae
Analogous vs Homologous Structures
Analogous structures = same function, different origin. Homologous = same origin, different function.
Analogous vs Homologous Structures
Two types of structural similarity — one shows evolution, one doesn't
Homologous structures: share common ancestry (human arm, whale flipper, bat wing — all same bone structure). Evidence for evolution. Analogous structures: same function but different origin (bird wing vs insect wing). Convergent evolution, NOT evidence of common ancestry.