bio test 4

heterotrophs

animals obtain energy and nutrients by eating other organisms

holozoic nutrition

organisms feed by ingesting solid matter which is then digested and absorbed into their bodies

saprophytism

feed on dead and decaying matter

tissues

groups of similar cells that act as a functional unit

embryonic development

animals typically develop from a fertilized egg through stages including a blastula

blastula

early embryonic stage consisting of a hollow ball of cells

Paleozoic era 541-252 MYA

cambrian explosion, many marine animals appeared, plants and animals began colonizing land, era ended with permian mass extinction - largest known mass extinction

mesozoic era 252-66 MYA

age of reptiles, dinosaurs, first mammals appeared, first birds evolved, flowering plants appeared and diversified, ended with mass extinction that wiped out all land dinosaurs

cenozoic era 66MYA - now

age of mammals, mammals became dominant, primates evolved and humans evolved

radial symmetry

body parts arranged around a central point, can be divided into smaller halves through multiple planes - jellyfish and are circular

bilateral symmetry

body has left and right sides, only one plane divides the body into mirror image halves - humans and butterflies

diploblastic

two embryonic tissue layers, ectoderm and endoderm, no true mesoderm - jellyfish

triploblastic

three embryonic tissue layers, ectoderm, endoderm and mesoderm - humans

ectoderm

develops into the outer body covering and nervous system

mesoderm

develops into muscles, connective tissue and many internal organs

endoderm

develops into the lining of the digestive tract and associated organs

cleavage

refers to the early cell division of an embryo

spiral cleavage

cells divide at angles, cells are arranged diagonally or offset and common in many protostomes

radial cleavage

cells divide into parallel or perpendicular to the axis, cells are stacked directly above one another, common in deuterostomes

determinate cleavage

cell fate is determined early, each cell has a specific development role, common in protostomes

indeterminate cleavage

cell fate is not determined early, early cells can develop into a complete embryo, common in deuterostomes

acoelomate

no body cavity between digestive tract and body wall - flatworms

pseudocoelomate

body cavity not completely lined by mesoderm - roundworms

coelomate

true body cavity completely lined by mesoderm - earthworms and humans

protostomes

first mouth, spiral Cleavage, determinate

deuterotomes

anus, radial cleavage, indeterminate, often by out pocketing of the archenteron

blastopore

opening that forms during early embryonic development when the embryo begins forming its digestive cavity - this forms mouth or anus

filter feeders

obtain food by filtering water through their bodies

ostia on sponge

small pores where water enters

choanocytes sponges

collar cells that capture food and move water

amoebocytes sponges

cells that transport and distribute nutrients

osculum sponges

opening where water leaves

cnidarians

jellyfish, corals, hydras, and sea anemones

characteristics of cnidarians

radial symmetry, diploblastic, gastrovascular cavity, cnidocytes, nematocysts, tentacles, poly or medusa

cnidocytes

specialized stinging cells used for defense and capturing prey

nematocysts

stinging structures inside cnidocytes that release harpoon like thread

cnidarians polyp

tube shape, mouth faces upward, usually attached to a surface, ex hydra

cnidarians medusa

bell shaped, mouth faces downward, free swimming, ex jellyfish

four classes of cnidarians

Hydrozoa, scyphozoa, cubozoa, anthozoa

hydrozoa

dominant polyp stage, some have both stages ex Portuguese man o war

Scyphozoa

medusa stage is dominant ex true jellyfish - moon jellyfish

cubozoa

medusa is cube shaped, box jellyfish

anthozoa

polyp form, ex corals and sea anemones

Platyhelminthes - flatworms

bilateral symmetry, triploblastic, acoelomate, cephalization, hermaphroditic,, incomplete digestive system, less volume more surface area

Turbellaria - Platyhelminthes - planarians

mostly free living, usually aquatic, mov using cilia and muscles, eyespots to detect light - only few are parasitic

Cestoda - platyhelminthes - tapeworms

all are parasitic, live inside digestive system of hosts, have a scolex (head) with attachment structures, body consists of structures called proglottids, no digestive tract, absorb nutrients through body surface

trematoda - platyhelminthes - flukes

all are parasitic, flattened leaf shaped body, suckers for attachment, often have complex life cycles involving multiple hosts

proglottids

units that contain sex organs and form a ribbon behind the scolex

mollusks

bilateral symmetry, soft bodies, most have a shell of calcium carbonate, muscular foot for movement, mantle which secretes the shell, visceral mass, most have radula for food, open circulatory system

gastropoda - mollusks - snails and slugs

usually have one shell or no shell, move with a muscular foot, radula, undergo torsion during development

bivalvia - mollusks - clams oysters muscles

two hinged shells, filter feeders, no radula, use gills for respiration and filter feeding

cephalopoda - mollusks - octopi, squid, cuttlefish, nautilus

reduced or no internal shell, foot modified into arms or tentacles, predators, well developed eyes and nervous system

polyplacophora - mollusks - chiton

eight overlapping shell plates, flattened bodies, live attached to rocks in marine environments, use radula to scrape algae

Scaphopoda - mollusks - tusk shells

long curved shell open at both ends, live buried in marine sediment, use tentacle like structures called captacula to collect food

annelids - segmented worms

bilateral symmetry, triploblastic, coelom, complete digestive tract, closed circulatory system, skeleton for movement, many have bristles called setae

oligochaete - annelids - earthworms

few setae per segment, no parapodia, mostly live in soil or freshwater, hermaphroditic

polycheata - annelids - bristle worms

many setae, have parapodia, mostly marine, often have distinct heads, usually separate sexes

hirudinea - annelida - leeches

suckers at both ends, lack setae, flattened bodies, parasites

nematodes - roundworms

cylindrical unsegmented bodies, bilateral, triploblastic, pseuodocoelomate, complete digestive tract, covered by flexible cuticle that molts as they grow, no circulatory system, free living and parasites

beneficial features of arthropods

exoskeleton, jointed appendages, segmented body and specialization

exoskeleton - arthropods

hard outer covering of chitin, protects the body, prevents water loss, provides support and attachment for muscles, most be molted (ecdysis) to allow growth

jointed appendages - arthropods

legs, antennae, mouthparts and other appendages have joints, allow specialized movement and function, can be adapted ofr