Exam II

eukaryotic, multicellular, cells lack cell walls, heterotrophic, sexual reproduction, developmental strategies

eukaryotic, multicellular, cells lack cell walls, heterotrophic, sexual reproduction, developmental strategies

What are the 6 characteristics of animals?

35

Approximately how many animal phyla are there?

body plan

set of morphological and developmental traits

symmetry, tissues, body cavities

groups of animals can be differentiated based on body plans… name 3 we will be looking at

radial symmetry

symmetry in which an organism is split down it’s central axis and can be cut in more than 2 ways

bilateral symmetry

symmetry in which an organism is cut from its top into two identical halves

diploblastic

when you have radial symmetry what type of tissue layers do you have?

triploblastic

when you have bilateral symmetry what type of tissue layers do you have?

diploblastic

meaning an organism has 2 layers of tissue (ectoderm, endoderm)

triploblastic

meaning an organism has 3 tissue layers (ectoderm, mesoderm, endoderm)

cleavage

rapid cell division in zygotes following fertilization which first forms an eight stage cell then a blastula

blastula

embryonic stage consisting of a multicellular hollow ball of cells produced by cleavage

gastrula

embryonic stage consisting of different tissue layers; created through gastrulation

gastrulation

the process in which cells at the surface of the blastula begin to move inwards to a more interior part of the cell

blastocoel, endoderm, ectoderm, archenteron, blastospore

What does a fully formed gastrula contain?

ectoderm

outermost tissue layer, forms the covering of the embryo surface

endoderm

innermost tissue layer; forms the lining of the digestive tube

mesoderm

middle layer; forms connective tissues

archenteron

a tube-like cavity formed in animal embryos during gastrulation.

coelom

the fluid-filled body cavity of an animal that contains the internal organs

coelomate

an animal which contains a true coelom and has a lining of mesoderm around it

psuedocoelomate

an animal which does not have a true coelom, has a “fake” coelom and does not have a mesoderm lining

aceolomate

an animal which has no coelom at all

protostomy

means first mouth

deuterostomy

means second mouth

protostome

which animal body plan?

• cleavage has an eight-cell stage which is spiral and determinate '

• in coelom formation it has solid masses of mesoderm split and forms the coelom

• the blastospore forms the mouth first then the anus

deuterostome

which animal body plan?

• eight stage cell is radial and indeterminate

• in coelom formation folds of archenteron form the coelom

• the blastospore forms the anus first then the mouth

B

At what developmental stage should one be able to first distinguish a protostome embryo from a deuterostome embryo?

A) Fertilization B) Cleavage C) Gastrulation D) Coelom formation

common ancestor

all animals share a ------

sponges

these are the basal animals

eumetazoa

this is the clade of animals with true tissues

bilaterians

most animals are -----

deuterostomia, ecdysozoa, lophotrochozoa

what are the three major clades of bilaterians

A

Which of the following is a characteristic unique to animals (not observed in other taxa)? A) gastrulation B) multicellularity C) sexual reproduction D) heterotrophic nutrition

invertebrates

What accounts for 95% of all known animal species?

platyhelminthes, syndermata, annedlia, mollusca

List the 4 phyla of Lophotrochozoa

nematoda, arthropoda

List the 2 phyla of Ecdysozoa

chordata, echinoderm

List the 2 phyla of Deuterostomia

D

The most ancient branch point in animal phylogeny is that between its lineages having

A) radial or bilateral symmetry. B) a well-defined head or no head. C) diploblastic or triploblastic embryos. D) true tissues or no tissues

porifera

• ‘sponges’

• basal animals

• lack true tissues

• sedentary

• live in marine or freshwater

• suspension feeders

ctenophora

• comb jellies

• debate on their phylogeny

• basal eumetazoans

cnidaria

• jellyfish, anemones, corals, hydras

• radial symmetry

• diploblastic

• sessile and motile forms (polyp and medusa)

• body plan is sac with central digestive compartment

• single opening as mouth and anus

• nerve net

cnidocytes

‘stinging’ cells of cnidaria; an explosive cell containing one large secretory organelle called a cnidocyst that can deliver a sting to other organisms.

cnidarians

What are the sister taxa to bilaterians?

acoela

What is the basal bilaterian clade?

bilaterians

What clade?

• bilaterial symmetry

• triploblastic development

• true coelom

• digestive tract with two openings

• central nervous system

lophotrochozoa

what major clade of the bilaterians?

• protostomy

• platyhelminthes

• syndermata (previously rotifers)

• annelida

• mollusca

platyhelminthes

what lophotrochozoa phyla?

• ‘flatworms’

• bilaterial symmetry

• acoelomate

• aquatic and damp terrestrial habitats

• gastrovascular cavity with a single opening

• some are parasitic

  • trematodes

  • tapeworms

  • flukes

syndermata (rotifers)

what lophotrochozoa phyla?

• live in aquatic and damp terrestrial habitats

• pseudocoelomate

• digestive tube with separate mouth and anus

• can reproduce by parthenogenesis

parthenogenesis

females produce offspring from unfertilized eggs

mollusca

what lophotrochozoa phyla?

• gastropods, bivalves, cephalopods

• most are marine

• coelomate

• open and closed circulatory systems

• soft bodied (protected by hard shell)

• intelligence in cephalopods

annelida

what lophotrochozoa phyla?

• 2 groups

  • polychaetes (bristle worms)

  • oligochaetes (earthworms, and leeches

• bodies composed of fused rings

• coelomate

• closed circulatory system

ecdysozoans

what major clade of bilaterians?

• protostomy

• ecdysis

• cuticle

ecdysis

shedding of cuticle

cuticle

tough outer coat (exoskeleton) providing support and protection

nematoda

what ecdysozoa phyla?

• ‘roundworms’

• parasitic

• reproduce by internal fertilization (sexually)

  • ex: trichinella spp., c. elegans (model organism)

arthropoda

what ecdysozoa phyla?

• segmented body plan

• hard exoskeleton (cuticle)

• open circulatory system

• specialized jointed appendages

  • walking

  • feeding

  • sensory reception

  • reproduction

  • defense

chelicerates, myriapods, crustaceans, hexapods

What are the 4 subphyla of arthropods?

chelicerates

what subphyla of arthropods?

• horseshoe crabs

• scorpions

• ticks

• mites

• spiders

myriapods

what subphyla of arthropods?

• centipedes

• millipedes

crustaceans

what subphyla of arthropods

• crabs

• lobsters

• shrimps

• barnacles

hexapods

what subphyla of arthropods?

• insects and relatives

deuterostomia

what major clade of bilaterians?

• shared developmental characteristics (deuterostomy)

• radial, indeterminate cleavage

• formation of the anus from the blastospore

echinoderms

what deuterostomia phyla?

• sea stars, sea cucumbers, sand dollars, sea urchines

• slow moving or sessile marine animals

• endoskeleton of ossicles

• hydrostatic skeleton

• external sexual reproduction

chordates

what deuterostomia phyla?

• has 4 defining characteristics

  • notochord

  • dorsal, hollow nerve cord

  • pharyengeal slits

  • post anal tail

D

Which of the following combinations of phylum and description is incorrect?

A) Nematoda–roundworms, pseudocoelomate B) Cnidaria–radial symmetry, polyp and medusa body forms C) Platyhelminthes–flatworms, gastrovascular cavity, acoelomate D) Porifera–gastrovascular cavity, coelom present

notochord, dorsal hollow nerve cord, pharyngeal slits, post anal tail

What are the 4 main derived characteristics of chordates?

D

Why are humans considered members of the chordates when we have no notochord, pharyngeal slits, or muscular, post-anal tail?

A) Basal chordates show all of these traits. B) Other similar traits appear in humans. C) Our nerve cord has replaced the notochord. D) These chordate traits appear in human embryos

cephalochordata

• lancelets

• look like anchovies but not an actual fish

• filter feeders, buriers posterior end to absorb water and any nutrients to get “food”

cephalochordata

what is the basal chordate?

tunicates

• previously urochordata

• adults are filter feeders

• a group of marine animals that spend most of their lives attached to docks, rocks or the undersides of boats

• has a larval stage

craniates

• chordates with a head

• derived characters

  • skull

  • brain

  • eyes and other sense organs

  • heightened metabolism (sophisticated circulatory system)

myxini

• hagfishes

• has slime glands which produce slime as a defensive mechanism

• could argue they have a vertebral column but not true vertebrates

vertebrates

• craniates with a backbone

• derived character of ------ is a vertebrae (encloses spinal cord)

petromyzontoda

• lampreys

• true fish on bottom of sea floor

• have a “suction cup” mouth

  • circular array of teeth

gnathostomes

vertebrates with jaws

chondrichthyans

jawed cartilaginous fishes; whole skeleton made of cartilage

• ex: blacktip reef shark, southern sting ray

osteichthyans

• bony fishes

• gnathostomes with bony endoskeleton

actinopterygii

• rayed-finned fishes

• fin has very thin rays called fin rays which are directly attached to radials

  • ex: tuna, salmon, sea horse, red lionfish

sarcopterygii

• lobed-finned fishes

• 2 phyla -- actinista, dipnoi

• the fins come off a small bone

• somewhat homologous to human limbs

tetrapod

• sarcopterygians with limbs

• derived characters

  • four limbs with digits

  • neck allowing separate movement of head

  • fusion of pelvic girdle to the backbone

  • ears for detecting airborne sounds

amphibians

• these have simple eggs with the embryo surrounded by a jelly coat

amniotes

these are tetrapods with amniotic eggs

reptiles

• derived characteristics

  • scales that create a waterproof barrier

  • shelled eggs, laid on land

• include lizards, snakes, turtles, crocodilians and birds

lepidosaurs, archosaurs

what are the two main clades of reptiles?

lepidosaurs

this reptilian clade includes tuataras and squamates (lizards and snakes)

archosaurs

this reptilian clade includes crocodilians, extinct dinosaurs and birds

anapsids

what are turtles?

pterosauria

sister taxa to dinosauria, flying dinosaurs

ornithischia

• “bird-hipped” dinosaurs

• walk on 4 legs

• herbivores

saurischia

• “lizard-hipped” dinosaurs

• herbivores and carnivores

• includes sauropods and theropods

sauropod

what saurischia dinosaur?

• herbivore

• long necked dinosaurs

• can be dozens of meters long

theropods

what saurischia dinosaur?

• carnivores

• has teeth and claws

aves

• birds

• saurischia

• derived characters

  • forelimbs develop into wings

  • keratinized feathers

  • hollow skeletons

  • loss of teeth

mammals

• amniotes with hair

• derived characters

  • mammary glands

  • hair

  • high metabolic rate

  • large relative brain size

  • differentiated teeth

• three main groups: monotremes, euthaerians, marsupials

monotremes

egg laying mammals

marsupials

mammals that have pouches that give birth early

eutharians

placental mammals (ex:humans)

B

Which choice best describes a reasonable mechanism for animal structures becoming better suited over evolutionary time to specific functions?

A) Animals with parents that continually try to improve their offspring's structures will become more abundant. B) Animals with mutations that increase their ability to reproduce will become more abundant. C) Animals that eat the most food become the most abundant. D) Animals with inventions that curtail reproduction will become more abundant.

anatomy

the study of the biological form of an organism