Bio-Exam 3 vocab

Animal

A multicellular, eukaryotic organism that is heterotrophic (obtains food by eating other organisms), lacks cell walls, and is typically capable of movement and responsive to stimuli

Heterotroph

An organism that cannot make its own food and must obtain nutrients by consuming other organisms

Autotroph

An organism that can produce its own food, usually through photosynthesis or chemosynthesis 

DIploid

A cell or organism that has two sets of chromosomes (one from each parent)

Haploid

A cell that has only one set of chromosomes (such as gametes, sperm and eggs)

Incomplete Metamorphosis

A developmental process in insects where the young (nymphs) resemble the adult form but are smaller and lack fully developed wings or reproductive organs

Complete Metamorphosis

A developmental process involving four distinct life stages, egg, larva, pupa, and adult (butterflies, beetles)

Choanoflagellates

Single celled or colonial protists considered the closest living relatives of animals; they have a collar of microvilli surrounding a flagellum used for feeding

Symmetry

The arrangement of body parts around a central axis or plane

Radial Symmetry

Body parts arranged around a central axis or plane

Bilateral Symmetry

Body can be divided into equal left and right halves (ex. humans, worms) associated with directional movement and cephalization (development of head.)

Asymmetrical

No symmetry or consistent body patter (ex. sponge)

What is the benefit of radial symmetry

Good for stationary or slow moving animals, can sense danger/food from any direction

What is the benefits of bilateral symmetry

Favors mobility, streamlined movement, and sensory concentration at the head

What is the benefits of assymetry

Suited to simple organisms adapted to regular habitats

Midsagittal Plane

Divides the body into equal left and right halves

Frontal (Coronal) Plane

Divides the body into front (anterior) and back (posterior) sections

Transverse Plane

Divides the body into upper (superior) and lower (interior) sections

Anterior

Toward the front or head end

Posterior

Towards the back or upper side

Ventral

Refers to the belly or the underside

Germ Layers

Primary layers of cells formed during embryonic development that give rise to all tissues and organs

Endoderm

Inner Layer that forms gut, digestive organs, lungs

Mesoderm

middle layer the forms muscles, bones, circulatory system, and reproductive organs

Ectoderm

Outer layer that forms skin, hair, nails, and nervous system

Segmentation

Division of the body into repeated sections or segments (e.x.

Diploblast

Organism with two gem layers (ectoderm and endoderm)

Triploblast

Organism with three germ layers (ectoderm, mesoderm, endoderm)

Coelom

A fluid filled body cavity completely lined by mesoderm tissue: cushions organs and allows internal movement

Acoelomate

No body cavity (ex. flatworms)

pseudocoelomate

body cavity partially line with mesoderm (ex. roundworms)

Coelomate

Body cavity fully lined with mesoderm (ex. humans, earthwormms)

Blastula

Early hollow ball of cells formed after fertilization; stage before gastrulation

Blastopore

Opening that forms during gastrulation

Vascular tissues

water and photosynthate conducting tissues. Present in all plant structures

Xylem

water conduction. Dead when functional. Water transport is from roots to leaves. Water transport is passive (does not require energy)

Phloem

Photosynthesis transport from source (leaves, stems) to sink. Sink may be root or developing flowers and fruits. Phloem and xylem are intimately connected. Water flow between xylem and phloem allows most transport of p