Chordate and Vertebrate Evolution

Flashcards summarizing key vocabulary and concepts from the lecture on chordate and vertebrate evolution.

Chordates

Animals that possess a notochord, dorsal hollow nerve cord, and pharyngeal slits at some stage of development.

Vertebrates

A subgroup of chordates that have a backbone or vertebral column.

Notochord

A longitudinal, flexible rod located between the digestive tube and the nerve cord, providing skeletal support.

Dorsal hollow nerve cord

A hollow tube that develops into the central nervous system.

Post-anal tail

A tail that extends past the anus, containing skeletal elements and muscles.

Pharyngeal slits

Grooves that develop into openings in the pharynx, modified for functions such as gas exchange in vertebrates.

Gill-arch hypothesis

A hypothesis suggesting that jaw structures evolved from gill arches in early vertebrates.

Amniotic egg

An egg that contains a protective amnion, allowing for development in terrestrial environments.

Tetrapods

Vertebrates that have four limbs.

Lobed fins

Fin structures in ancient lobe-finned fishes that are considered key evolutionary links to the first terrestrial vertebrates.

Dinosaurs

Extinct reptiles that were the dominant terrestrial vertebrates during the Mesozoic era.

Mammals

A monophyletic group of amniotes characterized by mammary glands that produce milk.

Ectotherms

Animals that rely on external sources to regulate their body temperature.

Endothermy

The ability of an organism to maintain a constant body temperature through metabolic heat production.

Monotremes

Egg-laying mammals such as the platypus.

Marsupials

Mammals that carry and nurse their young in pouches.

Eutherians

Placental mammals that give birth to live young that have developed inside the womb.

Phylogeny

The evolutionary history and relationships among a group of organisms.

Multicellular eukaryotes

Organisms composed of more than one cell, with cells that have a true nucleus.

Biosphere

The global sum of all ecosystems, where life exists on Earth.

Biodiversity

The variety and variability of life on Earth, encompassing species diversity, genetic diversity, and ecosystem diversity.