Summary of Lecture: Evolution and Diversity of Life

Flashcards created from lecture notes covering key biological concepts related to the evolution and diversity of life, including taxonomy, major groups of plants and animals, and important evolutionary theories.

Three-Domain Hypothesis

The classification of life into three domains: Bacteria, Archaea, and Eukarya.

Eukaryotes

Organisms whose cells have a nucleus enclosed within membranes; include animals, plants, fungi, and protists.

Endosymbiotic theory

The theory that mitochondria and plastids originated from free-living prokaryotes that were taken up by a host cell.

Alternation of generations

A life cycle characteristic of plants and some algae involving alternating between a haploid gametophyte stage and a diploid sporophyte stage.

Mycorrhizae

Symbiotic associations between fungi and the roots of plants, aiding in nutrient absorption.

Gymnosperms

Seed-producing plants that have seeds unprotected by an ovary or fruit, including conifers and ginkgoes.

Angiosperms

Flowering plants that produce seeds enclosed in fruit; the most diverse group of land plants.

Cephalization

The evolutionary trend where nervous tissue and sensory organs become concentrated at one end of the organism, forming a head.

Bilateral symmetry

Body plan in which the left and right sides are mirror images; typical of most animals.

Dorsal hollow nerve cord

A structure in chordates that develops into the brain and spinal cord.

Pharyngeal slits

Grooves that develop in the pharynx of all chordate embryos; they can develop into gills in aquatic species.

Lobed fins

Fleshy, limb-like structures that are precursors to limbs found in tetrapods, evolved from certain fish.

Amniotic egg

An egg with protective membranes that allow embryos to develop on land; characteristic of amniotes including reptiles and mammals.

Hox genes

A group of related genes that determine the body plan of an embryo along the head-tail axis.

Mutualism

A type of symbiotic relationship where both species benefit; e.g., fungi and plants in mycorrhizal associations.