General Biology Study Guide: Biodiversity, Evolution, and Ecology

Biodiversity and Classification

Domains and Kingdoms of Life

The diversity of life is organized into three domains: Bacteria, Archaea, and Eukarya. Each domain contains multiple kingdoms, which group organisms based on shared characteristics.

• Bacteria: Single-celled prokaryotes, found in many environments.

• Archaea: Single-celled prokaryotes, often found in extreme environments.

• Eukarya: Includes all eukaryotic organisms (plants, animals, fungi, protists).

Prokaryotes were the first life forms on Earth, predating eukaryotes.

Classification Systems

• Organisms are classified based on physical, genetic, and biochemical similarities.

• Phylogenetic trees show evolutionary relationships among species.

Plant Biology

Plant Life Cycles

Plants exhibit an alternation of generations life cycle, alternating between haploid (gametophyte) and diploid (sporophyte) stages.

• Sporophyte: Diploid stage that produces haploid spores via meiosis.

• Gametophyte: Haploid stage that produces gametes via mitosis.

Example: In mosses, the gametophyte is the dominant stage, while in flowering plants, the sporophyte is dominant.

Plant Structure and Function

• Roots: Anchor the plant and absorb water/nutrients.

• Stems: Support the plant and transport materials.

• Leaves: Main site of photosynthesis.

Fungi and Animal Diversity

Fungi

• Fungi are eukaryotic organisms that decompose organic material.

• They reproduce via spores and can be unicellular (yeasts) or multicellular (molds, mushrooms).

Animal Classification

• Animals are classified by body plan, symmetry, and developmental patterns.

• Major groups include invertebrates (e.g., insects, mollusks) and vertebrates (e.g., fish, mammals).

Evolution and Natural Selection

Mechanisms of Evolution

Evolution is the change in the genetic composition of populations over time. Key mechanisms include:

• Natural Selection: Differential survival and reproduction of individuals due to environmental pressures.

• Genetic Drift: Random changes in allele frequencies, especially in small populations.

• Gene Flow: Movement of genes between populations.

• Mutation: Source of genetic variation.

Speciation

• Speciation is the formation of new species, often due to reproductive isolation.

• Types of speciation include allopatric (geographic separation) and sympatric (without physical separation).

Phylogenetic Trees

Phylogenetic trees illustrate evolutionary relationships. Organisms sharing a recent common ancestor are closely related.

Ecology

Population Ecology

Population ecology studies the dynamics of species populations and how they interact with the environment.

• Population Growth: Can be exponential or logistic.

• Exponential growth equation: $N_t = N_0 e^{rt}$

• Carrying Capacity (K): Maximum population size an environment can support.

Community and Ecosystem Ecology

• Producers: Organisms that produce their own food (e.g., plants).

• Consumers: Organisms that eat other organisms.

• Decomposers: Break down dead organic matter.

Succession

• Primary Succession: Occurs in lifeless areas (e.g., after a volcanic eruption).

• Secondary Succession: Occurs in areas where a disturbance has destroyed a community but left the soil intact.

Genetics and Inheritance

Chromosomes and Genes

• Chromosomes: Structures that carry genetic information.

• Genes: Segments of DNA that code for proteins.

Types of Reproduction

• Asexual Reproduction: Offspring are genetically identical to the parent.

• Sexual Reproduction: Involves fusion of gametes, increases genetic diversity.

Sample Table: Comparison of Primary and Secondary Succession

Type of Succession	Starting Condition	Example
Primary Succession	No soil present	After lava flow
Secondary Succession	Soil present	After forest fire

Key Terms and Definitions

• Gametophyte: Haploid, gamete-producing phase in plants.

• Sporophyte: Diploid, spore-producing phase in plants.

• Photosynthesis: Process by which plants convert light energy into chemical energy.

• Mutation: Change in DNA sequence.

• Gene Flow: Movement of alleles between populations.

• Carrying Capacity: Maximum population size an environment can sustain.

Additional info:

• Some diagrams and handwritten notes referenced alternation of generations and phylogenetic trees. These are central to understanding plant life cycles and evolutionary relationships.

• Questions covered topics from Ch. 8-12 of a General Biology course, including biodiversity, evolution, ecology, and genetics.