Midterm Review

all the definitions we will ever need

Taxonomy

The organization and naming of organisms based on shared traits

Phylogeny

The evolutionary history of a species or related species

Polytomy

Phylogenetic branch from which more than two groups emerge

Systematics

The classification of organisms by determining evolutionary relationships

Homology

Phenotypic and genetic similarities due to shared ancestry

Analogy

Similarity due to convergent evolution

Convergent Evolution

Similar structures with similar functions between unrelated specie, evolved independently

Cladistics

Grouping organisms by common descent

Clade

Group of species that includes ancestral and descendant species

Monophyletic Clade

Clade with an ancestral species and ALL its descendants

Polyphyletic Clade

Clade with an ancestral species and descendants that span multiple clades

Paraphyletic Clade

Clade with an ancestral species and SOME of its descendants

Shared Ancestral Character

Trait that originated in an ancestor

Shared Derived Character

Trait that is original to a specific clade, and not present in a common ancetor

Unikonta

Supergroup of eukarya

Amoebozoans

Clade of unikonta including slime molds and amoeba

Amoeba

Unicellular organism

Lobular Pseudopodia Movement

Protruding arms from amoeba in a lobe-like way

Ophistokonts

Clade of unikonta including animals, fungi, and protist groups like choanoflagellates

Gap Junctions

Communication between cells

Tight Junctions

Holds cells together

Heterotrophic

Energy is gained from consuming energy releasing food substances

Epidermis

Outermost cell layer of porifera

Choanoderm

Outer cell layer of porifera that draws in food particles

Amoebocyte

Cell that absorbs the food for the choanoderm

Porocytes

Cells that make up the pores of a sponge

Spongocoel

Main central cavity of sponges

Totipotent Cells

Cell that can regenerate and have the ability develop into any cell type

Asymmetry

Lack of symmetry

Radial Symmetry

Several planes of symmetry in a body

True Tissues

Tissues isolated by membranous layers

Tissue

Group of specialized cells

Oral

Surface of body with mouth

Aboral

Surface of body opposite the mouth

Parazoa

Clade without true tissues

Eumetazoa

Clade with true tissues

Metazoa

Animalia clade

Cleavage

Phase with the repeated mitotic division of cells until a blastula is formed

Blastula

Hollow sphere of cells formed through cleavage of a fertilized egg

Gastrulation

Process in which the blastula transforms into the gastrula, forming the primitive gut + the blastopore

Diploblastic

Having two germ layers

Ectoderm (germ layer)

Outer embryonic layer, forms outer covering of animal

Endoderm (germ layer)

Innermost embryonic layer, forms digestive tract, liver, lungs

Epidermis, gastrodermis, mesoglea

Three tissue layers of Cnidarians

Mesoglea

Jelly tissue layer of Cnidarians

Polyp

Cnidarian body form where oral surface faces up

Medusa

Cnidarian body form where oral surface faces down

Anthozoa

Cnidarian clade including anemones and corals

Medusozoa

Cnidarian clade including jellies and hydrozoans

Triploblastic

Having three germ layers

Mesoderm

Germ layer in between the endoderm and ectoderm, forms muscles and most inner organs

Grades

Share key biological feature only

Eucoelomate

Possessing a true cavity completely lined with the mesoderm

Pseudocoelomate

Possessing a cavity partially lined with the mesoderm

Acoelomate

Possessing an incomplete cavity, no space between tissue layers

Bilateral Symmetry

One plane of symmetry in a body

Dorsal

Surface of the body with the back / uppermost

Ventral

Underside surface of the body

Anterior

Front / head end of the body

Posterior

Back / hind end of the body

Cephalization

Development of a head

Sessile

Immobile

Deuterostomia

Clade whose blastopore forms the anus first

Protostomia

Clade whose blastopore forms the mouth first

Porifera

Phyla including sponges

Cnidaria

Phyla including sea jellies, anemones, and corals

Echinodermata

Phyla including sea stars, urchins, dollars and cucumbers

Asteroidea

Echinodermata clade including sea stars

Echinodea

Echinodermata clade including sea urchins and sand dollars

Holothuroidea

Echinodermata clade including sea cucumbers

Cephalochordata

Chordate clade including lancelets that maintain the chordate characteristics across their entire lifespan

Urochordata

Chordate clade including tunicates whose chordate characteristics are only present in the larval stage

Notochord

Structure formed from cartilage that provides strength and support

Dorsal Hollow Nerve Chord

Dorsal to the notochord, structure that develops into the central nervous systems and spinal cord

Pharyngeal Gill Slits

Structure that allows for movement of water into mouth

Post-Anal Tail

Structure that contains skeletal elements and muscles, can be reduced during embryonic development

Segmentation

Phenomenon that consists of identical repeating body parts, present in Phyla Arthropoda, Annelida, and Chordata

Vertebrata

Chordate clade including foxes that possess a spinal cord and skull

Jawless Fish

Basal vertebrate

Gnathostoma Clade

Chordate clade including sharks, ray-finned fish, lobe-finned fish, amphibians, reptiles and mammals, characterized by the evolution of jaws

Osteichyan Clade

Chordate clade including ray-finned fish and lobe-finned fish, characterized by the evolution of lungs and bone

Tetrapods

Gnathosomes with limbs

Muscular Foot

Characteristic of mollusca that contributes to movement, prey capture and digging

Mantle

Characteristic of mollusca that is a water filled chamber with the gills, anus, excretory pores, and produces the shell

Radula

Characteristic of mollusca that functions like a tongue and captures food

Visceral Mass

Characteristic of mollusca that houses the internal organs

Gastropods

Molluscan clade that includes snails and slugs with a one piece shell

Bivalvia

Molluscan clade that includes clams and oysters with a two piece shell

Polyplacophora

Molluscan clade that includes chitons with several pieces of a shell

Cephalopoda

Molluscan clade that includes squids, octopi and cuttlefish

Spiral Cleavage

Cell divisions that do not take place parallel to eachother

Determinate

Cell fate is established early

Indeterminate

Cells retain the capacity to turn into a complete embryo late into embryonic development

Radial Cleavage

Cell divisions take place parallel to eachother, with left and right halves

Annelida

Phyla including segmented worms, earthworms, and leeches

Mollusca

Phyla including snails, slugs, clams, oysters, squids and octopi

Trochophore

Free swimming larva of annelids and molluscs

Errantia

Annelid clade that include actively mobile, segmented worms

Sedentaria

Annelid clade that includes less active segmented worms, like earthworms and leeches

Brachiopoda

Phyla including lampshells