Chapter 15 Zoology

multicellular, eukaryotic, heterotrophic, and lacks cell wall

distinguishing features of animals

heterotrophic

carnivores, herbivores, omnivores, and parasites

specialized tissues (almost all), motile (during some life stage) (can move), reproduce sexually, determined body plan

most animals have…

biomolecules → cells → tissues

most animals have specialized cells organized into tissues

tissues

group of similar cells with a common embryonic origin and perform related function

epithelial tissue

covers body surfaces and lines organs

connective tissue

support, structure, and transport (includes bone and blood)

muscle tissue

contracts to product movement

nervous tissue

transmits electrical signals

meiosis → haploid gametes → fertilization (egg + sperm) → diploid zygote → embryonic development

sexual reproduction

sexual reproduction

produces genetically unique offspring and increases diversity

asexual reproductions

budding, fragmentation, parthenogenesis

produces offspring genetically very similar or identical to parent

budding

a new individual forms from a “loud” or outgrowth of parent

fragmentation

part of animal separates and develops into complete individuals

ex: starfish

parthenogenesis

unfertilized egg develops into offspring

ex: ants

haploid, unfertilized eggs, diploid, fertilized eggs

in ants and honeybees, males are ______ and develop from _____________(parthenogenesis) and females are ______ and develop from _____________ (sexual reproduction)

fertilization, cleavcage, gastrulation, organogenesis

four stages of early development

zygote → morula (eight-cell stage) → blastula → gatrulation → gastrula

development after fertlization

blastocyst

has an “inner cell mass” that forms the embryo

mammalian balstula

trophoblast

outer layer of a blastocyst that forms the placenta

ectoderm

outer layer of gastrula

endoderm

inner layer of gastrula

body plans and embryonic development

scientists classify major groups of animals using characteristics of their…

tissues → symmetry → germ layers → body cavity → embryonic development

classification of animals

all animals

metazoa

parazoa

lack true tissues

includes sponges (porifera)

eumetazoa

have true tissues

includes essentially all other animals

asymmetrical

no pattern or symmetry in the animals body plan

radial symmetry

body plan has multiple planes of symmetry all crossing an axis through the center of the organism

bilateral symmetry

the body plan has only one plane of symmetry that creates two mirror-image sides

ex: humans

germ layers

during embryonic development, most animal species develop layers of tissues that develop into future tissues

diploblasts

develop two germ layers (ectoderm and endoderm)

animals with radial symmetry

simpler body plan

no mesoderm

radial symmetry

what is the body plan of diploblasts

triploblasts

develop three germ layers (ectoderm, mesoderm, and endoderm)

animals with bilateral symmetry

more complex body plan

includes most animal phyla

bilateral symmetry

what body plan do triploblasts have

ectoderm

Skin (epidermis), nervous system, sense organs, hair and nails develop from what germ layer?

ectoderm

outside + nervous system

mesoderm

muscles, bones, connective tissue, blood, hear, blood vessels, kidneys, reproductive organs develop from what germ layer?

mesoderm

movement + support + circulation

endoderm

lining of digestive and respiratory tracts, liver, pancreas, portions of several glands develop from what germ layer?

endoderm

internal linings + digestive organs

body cavities

fluid filled space between the digestive tract and body wall

acoelomate

no body cavity

pseudocoelomate

body cavity, not completely lined by mesoderm

coelomate (eucoelomate)

body cavity

completely lined by mesoderm

body wall

outer tube

digestive tract

inner tube

tissues, organs, and coelomic cavities

space between

protostomes

“mouth first”

blastopore develops into the mouth

a triploblast with a true coelom

ex: mollusks, annelids, arthropods

deuterostomes

“mouth second”

blastopore develops into the anus

mouth develops from another “second” opening

ex: echinoderms, chordates (including vertebrates)

blastopore

an opening that develops during gastrulation in early embryonic development

gastrulation

a series of cell movements that reorganizes the blastula into a gastrula and establishes the three germ layers forming the digestive tract

phylum porifera

an organism with no symmetry must belong to which phylum

organogensis

process of organ and tissue formation via cell division and differentiation

cleavage

development of an embryo from multiple rounds of mitotic cell division

fertilization

process of single sperm cell combining with a single egg cell to form a zygote

gastrulation

dramatic rearrangement of cells to create tissue layer

phylum arthtropoda

what phylum includes approximately 85% of known animal species, is the largest phylum in Kingdom Animalia

post-anal tail, notochord, pharyngeal slits

requirements of phylum chordata

Phylum Chordata

what phylum do these animas belong to: porpoise, mermaid, flamingo, sea turtle

tissues (yes or no), symmetry, germ layers (2 or 3), body cavity, embryonic development

how do we distinguish different groups of animals

heterotrophic

gets nutrition from ingestion, can’t make their own nutrients

eukaryotic, multicellular, heterotrophic, lacks cell wall

how do we recognize animals? what are the essential defining characteristics

filter feeding, hermaphroditic

characteristics of sponges

jellyfish, corals

what animals are part of the phylum Cnidaria

phylum porifera

what phylum is sponges

sponges (porifera)

the simplest animals

sponges (porifera)

specialized cells but not organized into true tissues or organs- classified as Parazoa

All aquatic (mostly marine)

adults are sessile (don’t move)

body designed to move water through the animal

hermaphroditic

water → ostia → spongocel → osculum

order of sponges water movement

ostia

sponge pores

spongocel

sponges central cavity

osculum

sponges opening at top

ostia, spongocoel, osculum

sponges structures

chaonocytes and amoebocytes

sponges cells

chaonocytes (collar cells)

flagellated cells that create water currents and capture food particles

trap small food particles and engulf them by phagocytosis

amoebocytes

mobile cells transport nutrients from collar cells to other cells

spicules (protein fibers)

in the Mesohyl that helps with water movement

true systems

sponges have no

diffusion

gas exchange and waste removal in sponges occur by…

intracellularly

Digestion in sponges occur…

asexually and sexually

sponges reproduce…

budding or fragmentation

asexual reproduction can occur in sponges through…

hermophroditic/monoecious

produce both sperm and eggs

ex: sponges

sponge reproduction

sperm released into water are carried to another sponge where fertilization occurs

Resulting larvae are free-swimming

hermaphroditic

Cnidaria

what phylum are jellyfish, corals, sea anemones, and hydras are a part of what phylum

chindarians

nearly all species are aquatic and marine

possess true tissues

radial symmetry

diploblastic

gastrovascular cavity for digestion

tentacles surround the mouth

cnidocytes

simple nerve net

lack true organs and organ systems

cnidocytes

specialized stinging cells in phylum cnidaria

cnidocyst

specialized stinging cell used for defense and capturing prey

nemocyst

inside cnidocyte

contains a highly coiled thread

stimulation triggers it to rapidly discharge, helping immobilize prey

polyp and medusa

cnidarian body plans

polyp

“stalk”

cnidarian

cylindrical/stalk shape

sessile (non motile)

mouth/tentacles point upwards

ex: sea anemones, corals, hydra

medusa

“bell”

cnidarian

bell/umbrella shape

motile

mouth/tentacles point downward

ex: jellyfish

diploblastic

cnidarians are ______ and posses two tissue layers

epidermis and gastrodermis

cnidarians tissue layers

mesoglea

in cnidarians, jelly-like, mostly non-living material between the tissue layers

specialized nerve, contractile, digestive and sensory calls

cnidarian specialized tissues

cnidarian digestive system

only one opening → functions as mouth and anus

food enters gastrovascular cavity where enzymes begin extracellular digestion

cells of gastrodermis absorb smaller food particles

completely intracellularly

cnidarians nervous system

nerve net rather than centralized brain

allows sensory cells to communicate with contractile cells and coordinate tentacle movement and swimming

diffusion

in cnidarians, gases and wastes are exchanged primarily by ________

sponges

specialized cells, but no true tissues