A3.1 Diversity of Organisms - Vocabulary Flashcards

Vocabulary flashcards covering key terms and concepts from the A3.1 Diversity of Organisms notes.

Variation between organisms

Great differences among organisms; variation exists even within a species (e.g., humans; identical twins are not exactly alike).

Species

Groups of organisms that share traits.

Binomial nomenclature

Two-word naming system for species: Genus (capitalized, italicized) and Species (lowercase, italicized).

Genus

The first word in a binomial name; a group of related organisms sharing similar traits.

Species (in binomial name)

The second word in a binomial name; identifies the specific species within the genus.

Biological species concept

A species is a group of organisms that can interbreed and produce fertile offspring.

Interbreed

To reproduce with another organism to produce offspring within the same species

Speciation

The process by which one species diverges into two or more distinct species.

Divergence during speciation

Populations accumulate differences over time, becoming noninterbreeding as they adapt to different conditions.

Chromosome number

The number of chromosomes characteristic of a species; can change slowly over evolutionary time.

Chromosome numbers (diversity)

Variation in chromosome counts among plant and animal species.

Karyotype

The number and appearance of chromosomes in a cell.

Karyogram

An image showing a karyotype with chromosomes arranged typically from longest to shortest.

Genome

All genetic information of an individual or group; the entire sequence of DNA in chromosomes.

Allele

Different forms of a gene.

SNP (Single Nucleotide Polymorphism)

A single base difference in the DNA sequence between individuals.

Transposons (junk DNA)

Jumping genes; DNA sequences that can move within the genome and often make up non-functional DNA.

Genome sequencing

Determining the full DNA sequence of an organism’s genome to map evolution, biodiversity, and medical insights.

DNA barcode

A short DNA sequence from a gene used to identify a species.

Dichotomous key

A identification key that uses a series of two-choice steps to identify organisms.

Horizontal gene transfer (HGT)

Transfer of genes between unrelated organisms, common in bacteria; unlike vertical transfer from parent to offspring.

Vertical gene transfer

Gene transfer from parent to offspring during reproduction.

Asexual reproduction

Reproduction without sexual mating; can lead to microspecies; biological species concept may not apply.

Microspecies

Very similar clones arising from asexual reproduction; a term used when the biological species concept does not apply.

Grizzly bear and polar bear (climate change context)

Hybridization can occur where ranges overlap; challenges strict species distinctions.

Chromosome number as a shared trait

Species often share a typical chromosome count; mismatched numbers can prevent interbreeding.

DNA barcodes in habitat identification (HL)

Using short DNA sequences to identify species present in a habitat from environmental samples.

Karyotype arrangement

Chromosomes arranged in pairs from longest to shortest; sex chromosomes at the end; bands used for identification.