Bacterial Diversity and Speciation

These flashcards cover key vocabulary and concepts related to bacterial diversity, speciation, and the fundamental principles of evolution discussed in the lecture.

Capsule

A gelatinous layer found in some bacteria that aids in attachment and protects from the immune system.

Cell wall

A rigid layer that maintains the shape of the cell and protects against osmotic pressure, often made of peptidoglycan in bacteria.

Plasma membrane

A selective barrier that encloses the contents of a cell and regulates the entry and exit of substances.

Cytoplasm

The jelly-like substance within a cell, where cellular processes occur, containing organelles and genetic material.

Ribosomes

Molecular machines that synthesize proteins by translating messenger RNA (mRNA) into amino acid sequences.

Plasmid

A small, circular piece of DNA that is separate from chromosomal DNA and can replicate independently.

Pili

Short, hair-like structures on the surface of bacteria that aid in attachment and genetic exchange (conjugation).

Bacterial Flagellum

A long, whip-like structure that helps bacteria move by rotating like a propeller.

Nucleoid

The region in a prokaryotic cell where the circular DNA chromosome is located.

Natural Selection

A process in which individuals with favorable inherited traits are more likely to survive and reproduce.

Allopatric Speciation

The formation of new species due to geographic isolation that prevents gene flow.

Sympatric Speciation

The formation of new species in populations that overlap geographically, without physical barriers.

Homology

Similarity in structure and genetics among species due to shared ancestry.

Artificial Selection

The selective breeding of organisms by humans to promote desirable traits.

Punctuated Equilibria

The theory that species remain stable for long periods, interrupted by brief episodes of rapid change.

Vestigial Structures

Remnants of organs or structures that had a function in earlier ancestors but are no longer functional.

Convergent Evolution

The process where organisms from different evolutionary lineages develop similar traits due to similar environmental pressures.

Gene Pool

The total collection of genes in a population at any one time.

Reproductive Isolation

Biological factors that prevent species from interbreeding and producing fertile offspring.

Hybrid Zone

A region where members of different species meet and interbreed, producing hybrids.

Polyploidy

The condition of having extra sets of chromosomes, often leading to speciation in plants.

Aneuploidy

The presence of an abnormal number of chromosomes in a cell, due to nondisjunction during cell division.

Adaptive Radiation

The rapid evolution of diversely adapted species from a common ancestor.

Gradual Speciation

A model of speciation that explains how species diverge gradually through a slow, continuous process.

Endemic Species

Species that are native to and found only within a specific geographical area.

Divergent Evolution

The process by which two or more related species become more dissimilar over time.

Biogeography

The scientific study of the geographic distribution of species and ecosystems.

Fossil Record

The history of life as documented by fossils, providing evidence of evolution.

Homologous Structures

Anatomical features in different species that share a common ancestor but may have different functions.