Unit 3 Study Guide

Cnidaria

Phylum of Eumetazoans “True animals”; have embryonic germ layers

Gastrodermis

the lining membrane of the alimentary tract of an invertebrate

Gastrovascular cavity

A central cavity with a single opening in the body of certain animals, including cnidarians and flatworms, that functions in both the digestion and distribu- tion of nutrients

Polyp

Mostly sedentary, can detach from surface; oral surface faces up; e.g. sea anemone, hydras

Oral surface

The surface of the body of an echinoderm where the mouth is situated; usually on the ventral side

Medusa

oral surface faces down; moves by drifting freely or body contractions; e.g. jellies

Cnidocytes

Stinging cells used for defense and capture of prey

Nematocysts

Organelle in Cnidocytes that eject a stinging thread to entangle or paralyze prey; some extremely harmful to humans

Medusozoa

Most spend majority of life in medusa form; jellies, box jelly, Portuguese Man O’ War

Anthozoa

exist only in polyp form; sea anemone corals; form symbiosis with zooxanthellae algae

Exoskeleton

a polyp secretion of hard calcium carbonate

Lophotrochozoa

Bilateral animals with protostome development

Lophophore

ciliated feeding structure around mouth

Trochophore

a type of developmental larval stage

Platyhelminthes

“Flatworms” in Lophotrochozoa; Acoelomates; live in aquatic and damp terrestrial environmentsl; lack circulatory system; some species are free-living and others are parasites

Pharynx

extended through mouth to feed and take up food. Undigested waste ejected here too

Turbellaria

Platyhelminthes; free-living carnivores; aquatic and terrestrial flatworms; move by undulation or gliding along secreted mucus layer; Planarians common in ponds and streams; some reproduce asexually by splitting down the middle

Cestoda

Platyhelminthes; tapeworms; parasites of vertebrates

Scolex

on anterior end, has hooks and suckers attach to intestinal lining of host; absorb nutrients from host through body, causes malnutrition

Proglottids

repeating sacs containing sex organs; sexual reproduction fills up with fertilized eggs; are shed in feces

Syndermata

Rotifers; Microscopic “wheel animals”; live in freshwater, marine and damp soil environments; multicellular but smaller than most protists; pseudocoelomates; reproduce via parthenogenesis

Rotifer

a tiny aquatic animal that is smaller than many unicellular protists

Alimentary canal

A complete digestive tract consisting of a tube running between a mouth and an anus.

Parthenogenesis

when females produce unfertilized eggs that develop into new females (asexual). Some species lack males entirely

Annelida

Segmented worms; live in aquatic and damp soil environments; Coelomates; have circulatory system, and alimentary canal; well developed nervous system; most have chaeta; segmented internally and externally

Chaeta

external bristles made of chitin; esp. on an annelid worm

Errantians

highly mobile marine worms

Sedentarians

less mobile worms; includes earthworms and leeches

Parapodia

lateral ‘paddles’ with several chaeta; used for movement and gas exchange

Hirudin

an anti-coagulant leeches inject

Earthworm

Annelid; Has a digestive system, nervous system, circulatory system; divided with septa; metanephridia; monoecious

Septa

partitions between segments

Metanphridia

used for waste removal and osmoregulation; invertebrate kidneys

Aboral Surface

The surface of the body of an echinoderm where the anus is situated; typically on the posterior side

Cnidarian Characteristics

Diploblastic; 10,000 species; Jellies, hydra, and corals; Radial symmetry

Cnidaria Anatomy

Diploblastic (epidermis and gastrodermis); Two body forms (Polyp and Medusa); No head or brain (rely on nerve net); Ring of tentacles around mouth/anus captures food and pushes into gastrovascular cavity

Diploblastic

To have two tissue types

Cnidaria Phylogeny

Medusozoa: majority of life in medusa form

Anthozoa: exist only in polyp form

Corals

Anthozoa; live in colonies; excrete exoskeleton; symbiosis with zooxanthellae algae; also trap zooplankton in tentacles

Medusozoa Reproduction

Polyp form (adult) produces tiny medusae via asexual budding. Medusae’s gametes fuse to produce zygote

Anthozoa Reproduction

Corals may reproduce sexually or asexually; coral spawning is when corals release eggs and sperm at the same time

Root

anchors plants in the soil, absorbs minerals and water, and stores carbohydrates

Lateral Root

a root that arises from the pericycle of an established root; spreading branch roots

Taproot system

Eudicot; one main vertical root, may be used for storage (e.g. carrot)

Fibrous root system

Monocot; many thin, branching roots with many lateral roots. Combats soil erosion

Root hair

tiny extension of a root epidermal cell growing just behind the root tip; increase surface area for absorption capability

stem

elongate the plant, elevate leaves and reproductive structures

Node

point of leaf attachment

Internode

stem sections between leaves

Apical bud

location of active cell division at shoot tips

Axillary bud

located at nodes, form lateral branches, thorns, etc.

Leaf

main photosynthetic organ in plants

Blade

broad portion of leaf

Petiole

joins leaf to the stem at a node

Dermal Tissue

outer protective covering, may be green, herbaceous, woody, etc.

Vascular tissue

xylem and phloem, found in a single cluster in roots or as vascular bundles in stems and leaves

Vascular bundles

clusters of xylem and phloem

Ground tissue

between dermal and vascular tissue; performs photosynthesis and storage

Guard cells

dermal tissue; pair of curved cells that surround stomata; open and close stomata by contracting and expanding

Xylem

moves water and minerals up from the roots

Tracheids

long, thin, tapered dead cells with pits that allow water to move through; in all vascular plants

Vessel elements

wider, shorter dead cells with perforated ends; in most angiosperms and some gymnosperms

Phloem

moves sugars down to other parts of the plant (e.g. roots)

Sieve-tube cells

living cells that make up ______; lack nucleus and ribosomes

Companion cells

cells connected to, and support metabolism of sieve tube elements

Active transport

pumping and cotransporting solutes across the cell membrane; traveling up the concentration gradiant

Passive transport

solutes flowing through ion channels and carriers down the concentration gradient

Osmosis

act of water molecules entering and exiting cells; includes Hypertonic, hypotonic, and isotonic solutions

Parenchyma

cells with thin, flexible walls; contain large vacuole; used for photosynthesis (mesophyll of leaves) and storage (roots, fruits, etc.)

Apoplastic route

Movement outside cell membranes; through extracellular spaces and through dead xylem vessels

Symplastic route

movement of the cytosol continuum via plasmodesmata of interconnected cells

Casparian strip

waxy belt blocks apoplastic routes into the xylem; forces a merge into symplastic route

Xylem sap

water and minerals being transported

Bulk flow

xylem sap being transported long distances by pulling it up the plant

Transpiration

loss of water from leaves via bulk flow

Cohesion-tension hypothesis

as water molecules evaporate out of stomata they pull up the water molecules behind them with their hydrogen bonds

Stomata

Pore in epidermis of plant that allows gas exchange between environment and interior of plant; opening regulated by guard cells that either traps water or allows transpiration

Translocation

the phloem transport of sugar from sources to sinks

Phloem sap

sugar, amino acids, and vitamins

Sugar sources

organs that are net producers of sugar (e.g. mature leaves)

Sugar sinks

organs that are net consumers or depositories of sugar (e.g. growing buds and leaves, roots, stems, and fruits)

C4 photosynthesis

Hot/dry conditions when stomata partially close: CO2 is fixed by PEP carboxylase in Mesophyll cells as Oxaloacetate. Malate transported into bundle sheath cells; delivers CO2 to Rubisco

C3 plant leaf anatomy

Vascular plants’ two organ systems

Root system and Shoot system

3 types of plant tissues

Dermal tissues, Vascular tissues, Ground tissues

Pavement cells

dermal tissues; flat cells of epidermis; protect inner cells and generally lack chloroplasts (not active photosynthesizers)

Monocot cross-section

scattered vascular bundles; little faces

Eudicot cross-section

vascular bundles in a ring

Hypotonic solution

A solution that will cause the cell to take up water; leads to turgid (normal) cell

Isotonic solution

A solution that causes no net movement of water into or out of a cell; leads to flaccid cell

Hypertonic solution

A solution that will cause a cell to lose water; leads to plasmolyzed cell

Long distance transport

Apoplastic route and Symplastic route

Short distance transport: Solutes

Movements of solutes and water across cell membranes; active and passive transport

Short distance transport: Water

water enters and exits cells via osmosis

C4 plant leaf anatomy

Heterotrophic

Must obtain organic compounds by consuming biomass. Ingest food and digest it inside the body.

Tissues

group cells that develop from embryonic layers and work as a unit

Blastula

A hollow ball of cells that marks the end of the cleavage stage during early embryonic development in animals

Gastrulation

The reorganization of cells into embryonic germ layers; a series of cell and tissue movement in which the blastula-stage embryo folds inward, producing a three-layered embryo