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animal characteristics

-multicellular heterotrophic eukaryotes
-no cell wall, cells held with collagen
-nerve and muscle tissue
-sexual reproduction

cleavage

mitotic divisions after fertilization

blastula

hollow ball of cells formed by cleavage

gastrulation

forms the primitive gut (adult body parts will arise from these embryonic tissues in the gastrula)

germ layers

Three main layers that form the various tissues and organs of an animal body.

ectoderm

"blue" gives rise to the outer surface and sometimes nervous system

endoderm

"yellow" lines the digestive tube (archenteron)

mesoderm

"red" forms muscles and many organs

Parazoa

no true tissue

Phylum Porifera

-(Parazoa)
-sponges
-sessile
-loose federation of cells,
-no mesoderm, asymmetrical
-filter feeders
-water into pores into spongocoel exits osculum
-food filtered out by choanocytes
-most are hermaphrodites

spongocoel

large central cavity of the sponge

osculum

A large opening on a sponge through which filtered water is expelled

choanocytes

flagellated collar cells in sponges that filter food

Eumetazoa

true tissue

Radiata

radial symmetry, diploplastic

diploblastic

have only 2 germ layers (ectoderm and endoderm)

Phylum Cnidaria

-(Eumetazoa, Radiata)
-hydra, jelly fish, sea anemonem coral
-gastrovascular cavity
-single opening for mouth/anus
-polyp and medusa form
-nematocysts
-sexual and asexual reproduction
-muscles and nerves in simplest form

nematocysts

stinging capsules located in special cells called cnidocytes (on tentacles)

cnidocytes

special cells with nematocysts

Phylum Ctenophora

-(Eumetazoa, Radiata)
-similar to Cnidaria
-comb jellies
-move by cilia fused into combs

Acoelomates

no coelom (body cavity)

Bilateria

bilateral symmetry, triploblastic

coelom

mesoderm lined body cavity besides the digestive cavity

Phylum Platyhelminthes

-(Eumetazoa, Bilateria, Acoelomate)
-flatworms
-some free living, some parasitic
-some cephalization
-no body cavity
-mesoderm gives rise to more complex organs and true muscle tissue
-one opening digestive tract

cephalization

concentration of sense organs and nerve cells at the front of an animal's body

Pseudocoelomates

triploblastic, body cavity but not completely enclosed by mesoderm

Phylum Rotifera

-(Eumetazoa, Bilateria, Pseudocoelomate)
-complete digestive tract (mouth and anus)
-parthenogenesis

parthenogenesis

process in which an unfertilized egg develops into a new individual

Phylum Nematoda

-(Eumetazoa, Bilateria, Pseudocoelomate)
-round worms
-many free living, some parasitic
-hookworm, pinworm, Trichina

Coelomates

body cavity completely enclosed by mesoderm besides digestive cavity, triploblastic

Protostomes

spiral, determinate cleavage (cells have designated purpose right away), blastopore becomes mouth

Phylum Nemertea

-(Eumetazoa, Bilateria, Coelomate, Protostome)
-proboscis worms (ribbon worms)
-complete digestive tract
-closed circulatory system
-many evolved away from coelom

P. Bryozoa, P. Phoronida, P. Brachiopoda

-(Eumetazoa, Bilateria, Coelomate, Protostome)
-Lophophorate animals, have horse-shoe shaped fold with cilia surrounding the mouth
-evolved into filter feeders
-complete digestive tract

Phylum Mollusca

-(Eumetazoa, Bilateria, Coelomate, Protostome)
-snails, slugs, oysters, octopus
-separate sexes or hermaphrodites (snails)
-muscular foot
-visceral mass
-mantle
-radula
-(3 classes to remember)

mantle

fold of tissue that covers visceral mass, often secretes shell

visceral mass

contains organs

radula

rasping organ that scrapes up food

Class Gastropoda

(Mollusca)
-stomach foot
-snails

Class Bivalva

(Mollusca)
-2 shells
-clams

Class Cephalopoda

(Mollusca)
-head foot
-octopus
-internal shell

Phylum Annelida

-(Eumetazoa, Bilateria, Coelomate, Protostome)
-segmented worms (earthworm)
-closed circulatory system
-cerebral ganglia & nerve cords
-metanephridia

metanephridia

each segment has 2 to excrete metabolic waste

Phylum Arthropoda

-(Eumetazoa, Bilateria, Coelomate, Protostome)
-regional segmentation
-jointed appendages
-exoskeleton
-molting
-extensive cephalization
-open circulatory system
-internal fertilization
-(5 classes to remember)

Class Arachnida

(Arthropoda)
-scorpians, spiders, ticks, mites
-cephalothorax with 6 pairs appendages
-2 pr chelicerae (sensing), 4 pair walking leg

Class Diplopoda

(Arthropoda)
-millipedes
-2 pr. leg per segment
-eat decaying matter

Class Chilopoda

(Arthropoda)
-centipedes
-1 pr. leg per segment
-carnivores
-poisonous

Class Insecta

(Arthropoda)
-wings are extension of cuticle
-most successful terrestrial
-tracheal system for gas exchange
-maliphigian tubules for excretion of metabolic waste
-cerebral ganglium
-many undergo complete or incomplete metamorphosis

Class Crustacea

(Arthropoda)
-crabs, lobsters, shrimp
-2 pr. antennae
-appendages on thorax and abdomen

Deuterostomes

radial, indeterminate cleavage (cells function not immediately determined), blastopore becomes anus

Phylum Echinodermata

-(Eumetazoa, Bilateria, Coelomate, Deuterostomes)
-sea stars, sea urchins
-water vascular system
-tube feet (for locomotion)
-external fertilization

water vascular system

network of hydraulic canals

Phylum Chordata

-(Eumetazoa, Bilateria, Coelomate, Deuterostome)
-notochord
-dorsal, hollow nerve cord
-pharyngeal gill slits
-muscular, post-anal tail
-segmented

notochord

flexible rod between digestive and nerve cords

dorsal, hollow nerve cord

from ectoderm rolling into a tube

Subphylum Urochordata

-Phylum Chordata
-Invertebrate
-sessile as adult

Subphylum Cephalochordata

-Phylum Chordata
-invertebrates
-may have evolved from paedogenesis of Urochordata

Subphylum Vertebrata

-Phylum Chordata
-neural crest
-high degree cephalization
-vertebral column and cranium
-closed circulatory system

neural crest

embryonic cells forming on dorsal part of neural tube: go to make up bones and cartilage of brain case (skull)

Class Agnatha

-jawless fish
-lampreys and hagfish
-considered a superclass divided into class myxini (hagfish) and class cephalaspidomorphii (lampreys)

Superclass Gnathostomata

- includes fish, reptiles, birds, mammals, and amphibians
-jaws work up and down
-2 sets of paired appendages

Class Chondrichthyes

-cartilage fish
-sharks, skates, rays
-lateral line system
-internal fertilization
-oviparous, ovoviviparious, and viviparous
-have to move to keep water over gills
-2 chambered heart

lateral line system

row of tiny organs sensitive to changes in water pressure, help detect sound waves and splashing

oviparous

eggs hatch outside body

ovoviviparous

eggs hatch inside uterus after being nourished by yolk

viviparous

give birth to live young that receive nourishment from mother's blood

Class Osteichthyes

-bony fish
-common fish are these
-lateral line system
-operculum, protective flap over gills
-can breathe while stationary
-swim bladder (air sac maintaining buoyancy)
-oviparous, external fertilization
-2 chambered heart
-(2 subclasses to remember)

Subclass Actinopterygii

(Osteichthyes)
-ray finned fish, most fish known today
-bass, salmon, perch, etc.

Subclass Sarcopterygii

(Osteichthyes)
-lobe-finned fish/lung fishes
-not many left, once dominant predator in shallow water
-can gulp air into lungs when ponds dry up
-gave rise to amphibians

Class Amphibia

-close ties with water
-must lay eggs in water or moist environment
-eggs are no shelled and dry out easily
-need moist skin to absorb oxygen from air
-external ferilization
-3 chambered heart
-(3 orders to remember)

Order Urodela

(Amphibia)
-tailed
-salamanders

Order Anura

(Amphibia)
-tailless
-frogs, toads

Order Apoda

(Amphibia)
-legless
-caecilians

Class Reptilia

-amniotic egg (can be laid on land & dry places)
-breathe only through lungs
-keratinized skin
-internal fertilization
-oviparous, some viviparous
-ectothermic
-3 almost 4 chambered heart
-(3 orders to remember)

Order Chelonia

(Reptilia)
-Turtles

Order Squamata

(Reptilia)
-lizards and snakes

Order Crocodilia

(Reptilia)
-crocodiles and alligators

keratinized skin

prevents dehydration

ectothermic

absorb external heat rather than generating their own (need less energy than mammals)

Class Aves

-birds
-closest relative to dinos
-amniotic egg
-hollow bones
-one ovary, toothless
-endothermic
-4 chambered heart
-internal fertilization
-keeled sternum
-feathers (light & strong, probably evolved from endothermy originally for insulation)

amniotic egg

shelled egg that retains water and can be laid on land or dry places

keeled sternum

anchors huge pectoral muscles necessary for flight

endothermic

they control their body temperature internally through metabolism

Class Mammalia

-hair
-mammary glands (millk)
-Endothermic (maintained by hair & fat)
-4 chambered heart
-internal fertilization
-viviparous (besides monotremes)
-differentiation of teeth
-include eutherians, monotremes, and marsupials

Eutherians

placental mammals
-extraembyronic membranes and uterine wall combine to form placenta that nourishes embryo
-longer pregnancy

Monotremes

egg laying mammals
-duck billed platypus and spiny anteater

Marsupials

-young born early and small
-must crawl to pouch where they nurse and complete development

Order Primata

-early ones arboreal, insectivorous, nocturnal
-gave rise to binocular vision
-nails instead of claws, grasping hands
-earliest were presimians (premonkeys)
-probably gave rise to anthropoids (monkeys, humans, apes)
-new & old world monkeys

New World Monkeys

-arboreal
-tails
-South America

Old World Monkeys

-some arboreal
-some on ground
-no tails
-Africa, Asia
-Apes

Australopithecenes

some of oldest hominids (4 mill years ago)

Lucy

best skeleton of Australopithecus afarensis, species remained unchanged for 1 million years until over taken

Homo habilis (handy man)

-had larger brain
-used tools
-arose 2.5 millions years ago
-say separate line from Australopithecenes

Homo erectus

-java man & beijing man
-found inside and outside of Africa
-migration because of meet eating?
-1.8 million years ago to 250,00 years ago
-larger brains
-include Neanderthal Man?? (130,000 - 35,000 years ago)
-abstract thought (burial rituals)
-speech?

Homo sapiens (wise man)

-modern man
-multiregional and monogenesis models

Multiregional model

modern humans arose in parallel in several areas around the world

Monogenesis model

modern humans arose in africa only from H. erectus and spread to other areas eventually replacing other hominids that had migrated earlier

Evidence of models for modern man

-only Africa contains fossils of ALL proposed stages of hominid evolution
-Neanderthal s and H. sapiens fossils coexisted and did not interbreed for 40,000 years in Israel
-mtDNA traced all modern humans back to Africa 200,000 years ago

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