IB Biology Topic A3.1: Diversity of Organisms Key Definitions

A binomial name is a two-part Latinized name that uniquely identifies a species. The first word represents the genus, and the second word represents the specific species within that genus.

The biological species concept (BSC) defines a species as a group of organisms capable of interbreeding and producing fertile offspring, emphasizing reproductive isolation.

An organelle found in plant and algal cells that is responsible for photosynthesis, the process of converting light energy into chemical energy

Chromosomes are the carriers of genetic information in all living organisms. They consist of two essential components: deoxyribonucleic acid (DNA) and proteins.

Classification is the process of organizing living organisms into groups based on shared traits or evolutionary origins.

A group of genetically identical organisms or cells derived from a single parent.

A tool that simplifies the identification of organisms. It operates through a series of paired statements that describe contrasting traits. Each decision point leads to another pair of choices until the correct identification is achieved.

DNA barcodes are short, standardized DNA sequences unique to each species, much like product barcodes in a store. These genetic "fingerprints" enable species identification, even from small or incomplete samples.

Environmental DNA (eDNA) refers to genetic material shed by organisms into their surroundings through skin cells, mucus, feces, or other biological materials. It enables species detection without direct observation.

The genome is the complete set of genetic instructions that determines the structure, function, and traits of an organism.

Horizontal gene transfer involves the direct exchange of genetic material between unrelated organisms, bypassing traditional parent-offspring inheritance. It is especially common in prokaryotes (bacteria and archaea).

pH is a measure of how acidic or basic a solution is, ranging from 0 (very acidic) to 14 (very basic).

Polyploidy is the duplication of an organism’s entire chromosome set.

SNPs are single base-pair changes in the DNA sequence.

Variation refers to differences in traits among individuals within a population, encompassing physical characteristics, behaviors, and genetic sequences.

Whole Genome Sequencing (WGS) is a DNA sequencing technique that determines the order of all or most of an organism's DNA bases.