IB DP Biology: Diversity of Organisms Flashcards

Comprehensive vocabulary flashcards covering the IB DP Biology syllabus on the diversity of organisms, including variation, species concepts, speciation, and genomic diversity.

Variation

The differences in characteristics among individuals of the same species.

Continuous Variation

Inherited traits that vary gradually across a range, such as height and skin color.

Discontinuous Variation

Traits that have distinct categories and are often controlled by a single gene, such as blood type or flower color.

Somatogenic Variation

Variation acquired during an organism's lifetime that is not inherited, such as muscle gain or tanning.

Blastogenic Variation

Inherited variation resulting from genetic differences in gametes.

Meristic Variation

Variation in the number of body parts, such as digits or petal number.

Substantive Variation

Variation in size, shape, or color, such as fruit size or hair color.

Heredity

The passing of traits from parents to offspring.

Population

A group of organisms of the same species living and interacting in the same area.

Species (Morphological Concept)

A group of organisms that look similar and are distinguished based on shared, observable physical traits or anatomy.

Cryptic Species

Species that are genetically distinct but visually identical, posing a challenge to the morphological species concept.

Biological Species Concept

A group of organisms that can interbreed and produce fertile offspring under natural conditions.

Ecological Species Concept

A species definition based on the ecological niche and role of organisms in the environment.

Phylogenetic Species Concept

A species definition based on genetic lineage and evolutionary history using DNA comparisons.

Speciation

The process by which one species splits into two or more new species, occurring when populations stop interbreeding and accumulate genetic differences.

Diploid Number ($2n$)

The total number of chromosomes in a somatic (body) cell, which is always an even number as chromosomes are in pairs.

Haploid Number ($n$)

Half the diploid number, found in gametes such as sperm or egg cells.

Karyotyping

The process of organizing and visualizing the chromosomes of an organism, typically from a mitotic cell in metaphase.

Karyogram

A visual chart showing homologous chromosome pairs ordered by length, banding pattern, and centromere position.

Genome

The entire set of genetic material in an organism, including all coding (genes) and non-coding regions.

Single-Nucleotide Polymorphisms (SNPs)

A change in a single DNA base at a specific position in the genome.

Copy Number Variations (CNVs)

Genetic diversity where sections of DNA appear in multiple copies in some individuals.

C-value Paradox

The observation that genome size is not directly related to organism complexity; for example, an amoeba can have a larger genome than a human.

Whole Genome Sequencing (WGS)

The process of determining the complete DNA sequence of an organism’s genome at a single time.

Horizontal Gene Transfer

The exchange of genes across species lines in bacteria via plasmids or viruses, which blurs biological species boundaries.

Dichotomous Key

A tool used to identify organisms by answering a series of binary (yes/no) questions about observable features.

Environmental DNA (eDNA)

Genetic material collected from soil, water, or air samples shed by organisms through skin cells, mucus, or feces.

DNA Barcoding

A technique using short, standardized regions of DNA (like the COI gene in animals) to identify and classify species.