Animal Characteristics & Development

Flashcards based on key concepts from the lecture on animal characteristics and development.

Multicellular

Organisms consisting of multiple cells.

Eukaryotic

Organisms whose cells contain a nucleus and organelles.

Heterotrophic

Organisms that cannot produce their own food and must consume other organisms.

Ectoderm

The outer germ layer that develops into the skin and nervous system.

Mesoderm

The middle germ layer that develops into muscles, bones, and the circulatory system.

Endoderm

The inner germ layer that develops into the digestive and respiratory systems.

Porifera

A phylum of animals that lack true tissues (sponges).

Cnidarians

A group of animals with two germ layers (e.g., jellyfish, hydra).

Triploblastic

Animals that have three germ layers, characteristic of all bilaterians.

Radial symmetry

Symmetry around a central axis, found in cnidarians and adult echinoderms.

Bilateral symmetry

Divisible into symmetrical halves on either side of a unique plane, found in most other animals.

Coelom

A body cavity completely lined by mesoderm.

Acoelomate

Animals that do not have a coelom, such as flatworms.

Pseudocoelomate

Animals with a false coelom, such as nematodes.

Coelomate

Animals with a true coelom, including annelids, mollusks, arthropods, echinoderms, and chordates.

Cephalization

The concentration of sensory organs and nervous tissue at the anterior end of the organism.

Protostomes

Animals in which the mouth develops first during embryonic development.

Deuterostomes

Animals in which the anus develops first during embryonic development.

Ecdysozoans

A group of protostomes that molt their exoskeleton.

Trochophore

A free-swimming larval stage found in some protostomes, such as mollusks and annelids.

Amphibians

The first tetrapods to move to land that require moist environments.

Ectotherms

Organisms that rely on external sources for body heat.

Endotherms

Organisms that can generate and regulate their own body heat.

Marsupials

Mammals that give birth to underdeveloped young and raise them in a pouch.

Platyhelminthes

A phylum of flatworms that are acoelomate and many are parasitic.

Nematodes

A phylum of roundworms that are pseudocoelomate with a complete digestive tract.

Arthropods

Animals with segmented bodies, jointed appendages, and exoskeletons made of chitin.

Mollusks

Coelomates with soft bodies often possessing a shell, known for four main parts.

Gastropoda

A class of mollusks characterized by a muscular foot for movement and often coiled shells.

Bivalvia

A class of mollusks with two hinged shells that are filter feeders.

Cephalopoda

A class of mollusks known for being smart, fast, having tentacles, and usually lacking an external shell.

Water vascular system

A system of canals and tube feet used for movement, feeding, and gas exchange in echinoderms.

Chordates

Animals characterized by a notochord, dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.

Epithelial tissue

Tissue that covers body surfaces and lines organs, characterized by tightly packed cells.

Apical surface

The free surface of epithelial tissue that faces the exterior or internal space.

Basement membrane

A thin layer that anchors epithelial tissue to underlying connective tissue.

Simple epithelium

A single layer of epithelial cells.

Stratified epithelium

Multiple layers of epithelial cells for added protection.

Squamous cells

Epithelial cells that are flat and thin.

Cuboidal cells

Epithelial cells that are cube-shaped.

Columnar cells

Epithelial cells that are tall and column-like.

Gland

A structure that secretes substances, either endocrine or exocrine.

Fibroblast

A cell in connective tissue that produces fibers and the ground substance.

Matrix

The non-living part of connective tissue made of ground substance and fibers.

Ground substance

Material in the matrix of connective tissue that can be liquid, gel, or solid.

Collagen

Strong and flexible fibers found in connective tissue.

Elastin

Stretchy fibers that provide elasticity in connective tissue.

Reticulin

Supportive fibers that form a mesh for soft tissues.

Connective tissue

Tissue that provides support, protection, and transport, characterized by fewer cells and more extracellular matrix.

Loose connective tissue

Connective tissue with fewer fibers and more ground substance, cushions organs.

Dense connective tissue

Connective tissue with more collagen fibers, which is strong and supportive.

Regular dense tissue

Dense connective tissue with aligned fibers, such as tendons.

Irregular dense tissue

Dense connective tissue with fibers in multiple directions, such as in the dermis.

Adipose tissue

A type of connective tissue that stores energy, cushions, and insulates.

Cartilage

A flexible type of connective tissue that provides support.

Blood

A fluid connective tissue that transports gases, nutrients, and immune cells.

Bone

A rigid connective tissue that supports the body, stores minerals, and produces blood cells.

Muscle tissue

Tissue specialized for contraction and movement.

Skeletal muscle

Voluntary, striated muscle that moves bones.

Cardiac muscle

Involuntary, striated muscle found in the heart that pumps blood.

Smooth muscle

Involuntary, non-striated muscle found in organs.

Nervous tissue

Tissue composed of neurons and glial cells, transmitting electrical signals.

Neuron

A nerve cell that transmits nerve impulses; consists of dendrites, soma, axon, and myelin sheath.

Glial cells

Cells that support neurons by providing insulation, nutrients, and protection.