What's in General Biology II

General Biology II is the organismal half of a two-semester majors biology sequence. Where the first semester works inside the cell, the second works at the scale of whole organisms, populations and ecosystems: how species change, what lives on Earth, how plants and animals function, and how they interact. Encodr's free General Biology II course follows OpenStax Biology 2e chapters 18 through 47 in book order, split into 18 units, 70 chapters, 1,328 study cards and 70 chapter notes, drawn from 31 sources.

Here is what each unit covers, in the order the course teaches it.

Evolution (units 1-3, OpenStax ch 18-20)

Unit 1, Evolution and Origin of Species (3 chapters). Darwin, Wallace and natural selection, the evidence for evolution, then speciation: species concepts, reproductive isolation, allopatric and sympatric speciation, hybrid zones, and gradualism versus punctuated equilibrium.

Unit 2, Evolution of Populations (3 chapters). Gene pools, allele and genotype frequencies, and Hardy-Weinberg equilibrium with its five conditions. Then the forces that break it: mutation, genetic drift (bottlenecks and founder effects), gene flow and natural selection, followed by directional, stabilizing and disruptive selection and sexual selection. This is the first math-heavy stretch; the Hardy-Weinberg guide walks through the calculations.

Unit 3, Phylogenies and History of Life (4 chapters). Reading phylogenetic trees, cladistics and homology, horizontal gene transfer and the web and ring of life models, and the geologic timeline with the five mass extinctions. See how to read a phylogenetic tree for the tree-reading skills.

Microbes and fungi (units 4-7, ch 21-24)

Unit 4, Viruses (3 chapters). Virus structure and classification, lytic and lysogenic cycles, animal virus replication, vaccines and antivirals, and prions and viroids.

Unit 5, Prokaryotes (4 chapters). Bacteria and archaea: diversity and cell structure, metabolism, bacterial disease, and the prokaryotes people depend on.

Unit 6, Protists (3 chapters). Endosymbiosis and the origin of eukaryotes, what defines a protist, the supergroups, and protist ecology.

Unit 7, Fungi (3 chapters). Fungal structure and the major phyla, decomposers, mycorrhizae and lichens, fungal pathogens, and fungi in human life.

Plants and animals (units 8-9, ch 25-29)

Unit 8, Plant Diversity (6 chapters). How plants colonized land from green algae, alternation of generations, bryophytes, seedless vascular plants, gymnosperms, angiosperms and the flower, and why seed plants matter.

Unit 9, Animal Diversity (9 chapters, tied with ecology for the most). Animal body plans and phylogeny, then a tour of the phyla: sponges and cnidarians, flatworms and other invertebrates, mollusks and annelids, arthropods, echinoderms and deuterostomes, chordates and fish, amphibians, reptiles and birds, and mammals with primate evolution.

Plant physiology (unit 10, ch 30-32)

Unit 10, Plant Form and Physiology (5 chapters). Plant tissues and organs, water and sugar transport (transpiration and pressure flow), plant hormones and tropisms, soil and plant nutrition, and plant reproduction.

Animal physiology (units 11-17, ch 33-43)

These units stay at intro depth. Encodr's MCAT and post-bac decks go deeper on human physiology.

Unit 11, Animal Body and Homeostasis (2 chapters). Tissue types, negative and positive feedback, and thermoregulation.

Unit 12, Nutrition and Digestion (2 chapters). Digestive systems and processes, nutrition and energy, and hormonal regulation of digestion.

Unit 13, Nervous and Sensory Systems (4 chapters). Neuron structure, resting and action potentials, synapses and nervous system organization, then somatosensation, taste, smell, hearing, balance and vision.

Unit 14, Endocrine System (2 chapters). Hormone types and how they act, and the major glands.

Unit 15, Musculoskeletal System (2 chapters). Skeletal systems, bone and joints, and muscle contraction.

Unit 16, Respiratory and Circulatory Systems (3 chapters). Gas exchange and breathing, blood and circulatory systems, and the heart and blood pressure.

Unit 17, Osmoregulation, Immunity and Reproduction (3 chapters). Osmoregulation and the kidney, innate and adaptive immunity, and animal reproduction and development.

Ecology (unit 18, ch 44-47)

Unit 18, Ecology and Conservation (9 chapters). Biomes and climate, population demography, exponential and logistic growth models, life history strategies, community interactions, succession, energy flow and trophic pyramids, biogeochemical cycles, and biodiversity and conservation. This is the second math stretch: population growth rates and the 10% rule for energy transfer between trophic levels.

How the course is built

Each chapter opens with a note card that teaches the topic, then mixes question types: short answer, multiple choice, cloze, typed answers for calculations, true or false, and sequence cards for ordered processes. Every numeric card (Hardy-Weinberg, growth models, trophic transfer) was recomputed by script before publishing. No card relies on an image, so structures are taught through description and function.

The course assumes you have taken first-semester biology. If you need to refresh cells, metabolism or Mendelian genetics, what's in General Biology I covers that side, and the first-year science courses overview lists all six courses.

Where the hard parts are

Most students find three things harder than expected:

• The diversity units (5-9). A lot of named groups with defining features. Comparison tables beat rereading.
• Hardy-Weinberg and population growth. Short formulas, but easy to set up wrong. The Hardy-Weinberg calculator is useful for checking practice answers.
• Physiology sequences. Action potentials, muscle contraction and the kidney are ordered processes, and exams ask what happens next.

How to study for General Biology II has a plan for each. The physiology units also borrow from physics: the action potential is a story about electric potential across a membrane, and vision depends on the eye working as a lens, both covered in College Physics 2.

The full course is free to study on Encodr: General Biology II flashcards.