Evolution, Protostomes/Deuterostomes, Animalia

Vocabulary flashcards related to the Origins of life and life beyond Earth,Protostomes vs Deuterostomes and Animal Phylogeny.

Big Bang

Cosmological event that occurred roughly 13.7 billion years ago, marking the origin of the universe.

Population III Stars

First stars formed approximately 400 million years after the Big Bang, composed solely of hydrogen (H) and helium (He).

Nucleosynthesis

Process by which Population III stars 'cooked' heavier elements through nuclear fusion, converting hydrogen into heavier atoms.

Supernovas

Explosions of Population III stars as they exhausted their nuclear fuel, resulting in the dispersion of dust that condensed into Population II stars.

Population II Stars

Stars formed from the dust of supernovas, containing more metals (elements heavier than H and He) than Population III stars.

Population I Stars

Metal-rich stars resulting from the gravity-driven condensation of Population II dust clouds, during which planets also formed.

Age of the Sun

Approximately 5 billion years (BYA); our sun is a Population I star.

Age of the Earth

Roughly 4.5 billion years (BY); oldest material found are zircon crystals, dated to 4.4 BY.

Biogenic Carbon

Carbon isotopes in samples that exhibit a slight bias for lighter (C13) isotopes over heavier (C14) isotopes, indicative of biological processes.

First Signatures of Life

Suggestive signal at 4.1 BYA; good signals of biogenic carbon in rocks from Greenland at 3.85 BYA.

Anaerobic Bacteria

Bacteria present around 3.6-3.7 BYA that produced methane or performed hydrogen sulfide photosynthesis.

Cyanobacteria

Bacteria present around 2.5 billion years ago that performed oxygen-forming photosynthesis.

Stromatolites

Mats of bacteria and sand, still found today, with fossil stromatolites dating back to 2.7 BYA.

Haldane and Oparin

Proposed the idea of a 'primeval soup' where organic molecules could be created in an oxygen-less atmosphere through sunlight.

Miller-Urey Experiment

Experiment demonstrating that complex organic molecules (amino acids) can be formed from simple organic molecules with electric discharges.

RNA World

Hypothesis suggesting that early life used RNA as the primary genetic material, capable of both cleaving itself and polymerase itself.

Steps in the Origins of Life

1. Formation of complex organic molecules; 2. Self-replicating systems; 3. Protein synthesis; 4. Compartmentalization: the first cell

Tholins

Organic compounds formed by solar UV or cosmic rays, often reddish in color, abundant in the solar system, and potentially a food source for early life.

Fox's Microspheres

Model system for compartmentalization where heating certain proteins leads to the spontaneous formation of microspheres, which can bud new spheres.

Catalytic RNAs

RNAs that can both cleave themselves and polymerase themselves, providing a solution to the 'chicken versus egg' problem in early self-replicating systems.

Hypercycles

Linking replication allows more information to be stably maintained in an early self-replicating system.

Exobiology/Astrobiology

The study of the possibility of life beyond Earth.

Ice-Shell Moons

Moons containing liquid water under a shell of ice, such as Europa and Enceladus, potential sites for life.

Cryovolcanism

Water and other volatiles that are the materials erupted from water volcanoes instead of silicate rock

Allan Hills 84001

Meteorite from Mars found in Antarctica, with suggestions of fossil life.

Titan

Largest moon of Saturn has a significant dense atmosphere, lakes of liquid methane and hydrocarbons, and cryovolcanos.

Tholins on Pluto

Organic compounds found on Pluto's surface that contribute to its reddish color.

Habitable Zone

Also called the Goldilocks zone, it's where planets are not too close (steam) nor too far (ice) from the star to maintain liquid water.

Fermi Paradox

The contradiction between the high probability of extraterrestrial civilizations and the lack of contact with such civilizations.

Great Filter

A hypothetical barrier that prevents most life from reaching the star-exploring stage.

Amniotic Egg

Watertight eggshell enclosing a membrane-bound food supply, water supply, and waste repository.

Placenta

Organ in placental mammals that facilitates the exchange of nutrients and waste between the mother and the developing fetus.

Lactation

Production of milk by female mammals to feed their offspring.

Echinoderms

Deuterostomes named for the spines or spikes observed in many species; larvae are bilaterally symmetric, adults are radially symmetric.

Water Vascular System

Unique morphological feature of echinoderms consisting of branching, fluid-filled tubes and chambers forming a hydrostatic skeleton.

Tube Feet

Elongated, fluid-filled structures in echinoderms that project outside the body and are involved in motion along a substrate.

Chordates

Defined by the presence of pharyngeal gill slits, a notochord, a dorsal hollow nerve cord, and a muscular post-anal tail.

Notochord

A supportive but flexible rod that runs the length of the body in chordates.

Dorsal Hollow Nerve Cord

A bundle of nerve cells running next to the notochord in chordates.

Urochordates (Tunicates)

Subphylum of chordates with pharyngeal gill slits present in both larvae and adults; notochord, dorsal hollow nerve cord, and tail only in larvae.

Cephalochordates (Lancelets)

Small, mobile suspension feeders that look somewhat like fish; retain the notochord in adults, which functions as an endoskeleton.

Vertebrates

Chordates in which the dorsal hollow nerve cord is elaborated into the spinal cord.

Tetrapods

First vertebrates that could reproduce on land.

Mammals

Endotherms; have hair or fur to insulate the body; mammary glands for lactation; a monophyletic class divided into Monotremata, Marsupiala, and Eutheria.

Monotremata

Most ancient group of mammals; lay eggs; lower metabolic rates than other mammals; found only in Australia and New Zealand.

Marsupiala

Marsupial females have a placenta, but the young are born poorly developed after a short embryonic period. They continue to develop while attached to their mother’s nipple

Eutheria

Placental mammals; young are much better developed at birth than those of marsupials; internal fertilization and viviparous.

Reptiles

Monophyletic group; one of the two major living lineages of amniotes; adapted to life on land with scales and well-developed lungs.

Aves (Birds)

Birds only endotherms within the Reptilia.

Protostomes

Bilaterally symmetric, triploblastic, coelomate animals divided into Lophotrochozoa and Ecdysozoa.

Lophotrochozoa

One of the two major clades of protostomes; include molluscs, annelids, and flatworms.

Ecdysozoa

One of the two major clades of protostomes; grow by molting, shedding of the soft cuticle or hard exoskeleton; include roundworms and arthropods.

Protostome Development

Pore becomes mouth, spiral cleavage, and coelem formation by spliting.

Deuterostome Development

Pore becomes anus, radial cleavage, and coelem formation by mesoderm pockets pinch off of gut.

Coelom

An enclosed, fluid-filled body cavity in humans.

The Arthropod Body Plan

Arthropods have segmented bodies that are organized into prominent regions, usually called the head, thorax, and abdomen. And are distinguished by their jointed limbs and an exoskeleton made of chitin.

Acoelomate

Triploblasts that do not have a coelom.

Coelomate

Triploblasts that posses a coelem.

The Molluscan Body Plan

The molluscan body plan is based on three major components: The foot, a large muscle located at the base of the animal and usually used in movement, The visceral mass containing most of the internal organs and external gill, and The mantle, a tissue layer that covers the visceral mass and secretes a shell in some species.

Water loss adaptation.

To make the transition to land, new adaptations allowed protostomes to exchange gases and avoid drying out.

Lophophore

A specialized structure that rings the mouth of these animals and functions in suspension feeding.

Trocophores

Type of larva common to several phyla of lophotrochozoa.

Corona

Cluster of cilia at their anterior end that is used for suspension feeding.

Annelida (Segmented Worms)

Annelids have a segmented body plan and a coelom that functions as a hydrostatic skeleton.

Chelicerae

Appendages found near the mouth that are used in feeding, defense, copulation, movement, or sensory reception.

Metamorphosis

The change from juvenile to adult body type.

Holometabolous metamorphosis

Complete metamorphosis. Juvenile individual is called a larva and looks quite different from the adult form. When the larva has grown enough, it encases itself and becomes a pupa; in this stage it is remodeled into an adult.

Hemimetabolous metamorphosis

Incomplete metamorphosis. The juvenile form is called a nymph and looks like a miniature adult.

Viviparous

Embryos may be retained in the female's body during development.

Oviparous

Eggs may be laid outside to develop independently of the mother.

Sessile

Fixed in one place; immobile.

Cnidocyte

A specialized cell that is used to capture prey.

Ecdysozoa

One of the two major clades of protostomes; grow by molting, shedding of the soft cuticle or hard exoskeleton; include roundworms and arthropods.

Protostome Development

Pore becomes mouth, spiral cleavage, and coelem formation by spliting.

Deuterostome Development

Pore becomes anus, radial cleavage, and coelem formation by mesoderm pockets pinch off of gut.

Coelom

An enclosed, fluid-filled body cavity in humans.

The Arthropod Body Plan

Arthropods have segmented bodies that are organized into prominent regions, usually called the head, thorax, and abdomen. And are distinguished by their jointed limbs and an exoskeleton made of chitin.

Acoelomate

Triploblasts that do not have a coelom.

Coelomate

Triploblasts that posses a coelem.

The Molluscan Body Plan

The molluscan body plan is based on three major components: The foot, a large muscle located at the base of the animal and usually used in movement, The visceral mass containing most of the internal organs and external gill, and The mantle, a tissue layer that covers the visceral mass and secretes a shell in some species.

Water loss adaptation.

To make the transition to land, new adaptations allowed protostomes to exchange gases and avoid drying out.

Lophophore

A specialized structure that rings the mouth of these animals and functions in suspension feeding.

Trocophores

Type of larva common to several phyla of lophotrochozoa.

Corona

Cluster of cilia at their anterior end that is used for suspension feeding.

Annelida (Segmented Worms)

Annelids have a segmented body plan and a coelom that functions as a hydrostatic skeleton.

Chelicerae

Appendages found near the mouth that are used in feeding, defense, copulation, movement, or sensory reception.

Metamorphosis

The change from juvenile to adult body type.

Holometabolous metamorphosis

Complete metamorphosis. Juvenile individual is called a larva and looks quite different from the adult form. When the larva has grown enough, it encases itself and becomes a pupa; in this stage it is remodeled into an adult.

Hemimetabolous metamorphosis

Incomplete metamorphosis. The juvenile form is called a nymph and looks like a miniature adult.

Viviparous

Embryos may be retained in the female's body during development.

Oviparous

Eggs may be laid outside to develop independently of the mother.

Sessile

Fixed in one place; immobile.

Cnidocyte

A specialized cell that is used to capture prey.

Radial Symmetry

Symmetry in which the body is arranged around a central axis.

Bilateral Symmetry

Symmetry in which the body can be divided into two mirror-image halves.

Triploblastic

Having three germ layers: ectoderm, mesoderm, and endoderm.

Protostome

An animal whose mouth is formed from the blastopore.

Deuterostome

An animal whose anus is formed from the blastopore.

Coelom

A body cavity completely lined with mesoderm.

Cephalization

The concentration of sensory and neural organs at the anterior end of the body.