animal bio exam 2

taxonomy

discipline of classifying living things

systematics

species relationship and evolution over time

hierarchical system

Linnaeus designed current scheme of classification: kingdom, phylum, class, order, family, genus, species

taxon and taxa

a group of organisms at any Linnean rank with a scientific name

binomial nomenclature

Genus, specific epithet

common descent

when one species is the ancestor to two or more species later in time

biological species concept

proposed by dobzhansky and mayer, a species is a community of populations reproductively isolated from others that occupy a specific niche in nature

evolutionary species concept

a single lineage of ancestor-descendant populations that maintains its identity from other such lineages and that has its own evolutionary tendencies and historical fate

phylogenetic species concept

irreducible grouping of organisms diagnosibly distinct from other such groupings and within which there is a parental pattern of ancestry and descent

character

a certain trait that evolves along the ancestry tree

homology

character similarly resulting from common ancestry. for example, four legs in group tetrapoda

homoplasy

character similarly involved in unrelated groups. for example, warmed blood in unrelated birds and mammals

ancestral character state

traits that are present in the common ancestor of a group and are retained across multiple descendant species

derived character state

traits that evolved more recently in a particular lineage and make it distinguishable from its ancestors or other particular groups

clade

group of organisms that includes its common ancestor and its descendants

cladogram

subset of phylogenetic tree

monophyly

group that includes a single common ancestor and all of the descendants of that ancestor

paraphyly

group that includes the common ancestor and some descendants but not all descendants

polyphyly

a group that does not include the common ancestor or that includes descendants of more than one ancestor

why are linnean ranks not informative and will not be used in the future

they do not necessarily represent evolutionary distances, such as one family containing far more diversity than another family

why do paraphyletic and polyphyletic taxa not reflect evolution

one excludes some descendants, and the other combines unrelated organisms based on superficial similarities which ignores ancestry

why do monophyletic taxa reflect evolution

includes ancestor and all descendants

periostracum

within mollusks; thin, tough, organic covering secreted by the mantle

radula

within mollusks; one of the key characteristics; protruding, rasping, tongue like organ that rasps off particles of food from surfaces

trochophore larva

all mollusks (except for cephalopoda) go through this stage; free-swimming, ciliated larval stage “wheel-bearing larva”

veliger larva

larval stage that follows the trochophore stage in many mollusks

monoplacophora

mollusks with a single, rounded shell. resemble limpets

polyplacophora

chitons; mollusks with 8 plates

osphradia

mollusks; pigmented chemosensory epithelium patch in the mantle cavity that functions as a chemoreceptor

mantle

mollusks; sheath tissue on each side of the body, secretes shell when present

mantle cavity

mollusks; houses the gills or lungs that develop from the mantle

what is new with mollusks?

true coelom, protostomes, triploblasts, mantle, shell, radula, specialized gills, advanced nervous systems

distinctive characteristics of mollusks

four main defining structures: foot, radula, mantle, shell

gastropoda

mollusks; have well developed foot, shell is univalve (when present), mostly herbivores

bivalvia

mollusks; mussels, body compressed between two hinged shells

cephalopoda

mollusks; squids, marine predators, foot modified into tentacles and arms, well developed eyes and brain

in mollusks, what does the coelom house

the heart

clitellum

reproductive structure on class clitella that is a defining characteristic

cocoon

in earthworms, after mutual copulation, each worm secretes a mucus tube that hatches young worms

septa

annelids; internal walls separating body segments

prostomium

head of annelids, anterior lobe in front of the mouth

peristomium

annelids; segments posteriorly to the head, body region surrounding the mouth

pygidium

annelids; terminal region containing the anus

peritoneum

annelida; lines body wall and forms dorsal and ventral mesenteries

setae

tiny chitinous bristles, absent in leeches, long ones help aquatic worms swim

metamerism

division of body into repeated segments; muscle segments

what is new with annelids

metamerism, large coelom, more efficient locomotion, bilateral, triploblastic, protostomia

distinctive features for annelids

metamerism, coelom, setae (most)

reproduction in earthworms

hermaphrodites (monoecious), mucus secreted by clitellum holds worm together for sperm exchange, cocoon produced

hirudinea

annelids; leeches, have no setae or septa

polychaeta

annelids; sandworms, bloodworms, sea mice; parapodia, many setae, eyes vary from simple eyespots to well-developed organs, dioecious external fertilization

oligochaeta

annelids; earthworms; clitellum, scavengers, long digestive tract, closed circulatory system, nephridia for excretion, hermaphrodism

tagma

segmented bodies with joint appendages, functional body regions formed by fused segments

chitin

arthropoda; strong exoskeleton material

ecdysis

periodic molting/shedding of exoskeleton

uniramous

single branched appendage

biramous

di-branched appendage

carapace

arthropods; protective dorsal shell or shield

ommatidium

arthropods; individual visual unit of compound eyes

entomology

study of insects

phytophagous insect

plant eating insect

saprophagous insect

feeds on decaying organic matter

hematophagous insect

feeds on blood

hyperparasitism

a parasite who parasitizes another parasite

parasitoids

organisms whose larvae develop within the host and eventually kill it

metamorphosis

transformation during development

holometabolous

complete metamorphis from egg to larva to pupa to adult

instar/larva

immature feeding stage

pupa

transformation stage

adult

sexually mature stage

hemimetabolous

incomplete metamorphosis from egg to nymph to adult

nymph

immature stage resembling small adult

ametabolous

no metamorphosis

diapause

dormant developmental period, depends on seasons

bioluminescence

production of light through chemical reactions

why are arthropods so diverse and abundant

versatile exoskeleton, appendages for more efficient locomotion, highly developed sensory organs. complex behavior patterns and ability to form social groups, body segmentation

trilobita

arthropoda; extinct organism with head, thorax, and pygidium

chelicerata

arthropoda; class merostomata (horseshoe crabs) and arachnida (spiders, scorpions); have chelicerae and pedipalps, two body tagma

myriapoda

arthropoda; class chilopoda (centipedes) and diplopoda (milipedes); two tagma including head and trunk, uniramous and biramous, carnivorous and herbivorous

crustacea

arthropoda; class malacostra (crayfish); two tagma including cephalothorax and abdomen, two pairs of antennae, biramous appendages

hexapoda

arthropoda; class insecta (grasshoppers); three tagma including head, thorax, and abdomen, uniramous appendages, typically two pairs of wings

what is new with arthropods

more complex digestive system, social behavior and ability to form organized communities, complex nervous system, flight, articulated legs

distinctive features for arthropods

chitinous exoskeleton, jointed appendages, tagmata, ecdysis

distinctive features for crustaceans

two pairs of antennae, biramous appendages, usually aquatic, gills, “soft-shell”

distinctive features of hexapoda

three tagmata, three pairs of legs, one pair of antennae, usually wings, uniramous appendages

what is one contribution of arthropods to the evolution of more advanced groups like chordates

segmentation, specialized appendages, complex organ systems

head-foot region and visceral mass

two regions of the mollusk body plan

layers of a mollusks shell

outer periostracum, middle prismatic layer, and inner nacreous layer

cephalopod circulatory system

closed

class caudofoveata

mollusk; worm like marine organism with no shell but covered in calcareous scales

class solenogaster

mollusks; resemble claudofoveates but have no true gills

class scaphopoda

mollusks; have tusks, sedentary and marine

gastropod reproduction

dioecious and monoecious

cephalopoda reproduction

dioecious, spermatophores

acari

arthropoda, chelicerata; ticks and mites, fused cephalothorax and abdomnen

ixodes

genus of acari, transmit lyme disease

tagmata of insecta

prothorax, mesothorax, metathorax

digestive system of insecta

foregut, midgut, hindgut

foregut

insecta; mouth, esophagus, crop, proventriculus

midgut

insecta; stomach, gastric ceca