Bio1220 - Lecture 16 - Intro to the Animal Phylogeny

animals

• multicellular heterotrophic aquatic or terrestrial eukaryotes

• no cell walls

• feeds by ingestion; consumed food is broken down using internal digestive enzymes

• lives in all possible environments (marine, freshwater, terrestrial, aerial, within other organisms)

• reproduces sexually

  • certain ones are also capable of asexual reproduction

no

Do animals have cell walls?

ingestion

• consumed food is broken down using internal digestive enzymes

• animals feed by this

sexually

Do animals reproduce sexually or asexually?

diploid

Multicellular animals are [diploid or haploid].

unicellular gametes

What is the only haploid stage in the animal life cycle?

gametes

• produced by meiosis within the diploid gonads (ovaries, testes)

• undergoes fertilization to produce a diploid zygote

meiosis

In animal reproduction, do the gametes undergo meiosis or mitosis within the diploid gonads?

a diploid zygote

In animal reproduction, gametes undergo fertilization to produce what?

animal zygote

• undergoes cleavage

  • repeated rounds of mitosis & cytokinesis give rise to a hollow ball of cells

blastula

• the early embryo

• undergoes gastrulation - one end folds inward into the blastocoel

blastocoel

the hollow interior of the blastula (early embryo)

cleavage

In animal development, the zygote undergoes what?

gastrulation

In animal development, the blastula undergoes what?

blastula gastrulation

• one end of the blastula folds inward into the blastocoel

• produces:

  • an outer tissue layer (ectoderm)

  • an inner tissue layer (endoderm)

  • a space between the two tissue layers (blastocoel)

  • an external opening (blastospore) leading to the embryonic gut (archenteron)

ectoderm

a product of blastula gastrulation; outer tissue layer

endoderm

a product of blastula gastrulation; inner tissue layer

blastocoel

a product of blastula gastrulation; a space between the two tissue layers

blastospore

a product of blastula gastrulation; an external opening leading to the embryonic gut (archenteron)

archenteron

a product of blastula gastrulation; an external opening (blastospore) leading to the embryonic gut

gastrula

• the animal embryonic stage

• undergoes further embryonic development, including mesoderm formation & organogenesis to produce the juvenile animal

  • in many species, the juvenile stage is a larval form, where the larva will ultimately undergo metamorphosis, giving rise to the adult animal

animal reproduction

• animals reproduce sexually

  • certain animals are also capable of asexual reproduction

• multicellular animals are diploid

  • unicellular gametes represent the only haploid stage in the animal life cycle

    • gametes are produced by meiosis within the diploid gonads

    • gametes undergo fertilization to produce a diploid zygote

animal development

• the zygote undergoes cleavage

  • repeated rounds of mitosis & cytokinesis give rise to a hollow ball of cells

• this early embryo is called a blastula

  • the hollow interior is called the blastocoel

• the blastula undergoes gastrulation

  • one end of the blastula folds inward into the blastocoel

  • gastrulation produces:

    • an outer tissue layer (ecotderm)

    • an inner tissue layer (endoderm)

    • a space between the two tissue layers (blastocoel)

    • an external opening (blastospore) leading to the embryonic gut (archenteron)

• this embryonic stage is called a gastrula

• the gastrula undergoes further embryonic development, including mesoderm formation & organogenesis, to produce the juvenile animal

• in many species, the juvenile stage is a larval form

  • the larva will ultimately undergo metamorphosis, giving rise to the adult animal

sponges/porifera

• do not possess true tissues

• they’re simply an aggregation of specialized cells

• does not exhibit body symmetry - they’re asymmetrical

cnidarians

• possess two tissue layers - ectoderm & endoderm

• this condition is called diploblastic

• displays radial symmetry

they don’t possess true tissues

If any, what and how many tissue layers do sponges/porifera possess?

2; ectoderm & endoderm

If any, what and how many tissue layers do Cnidarians possess?

diploblastic

the condition where an organism possess 2 tissue layers

3; ectoderm, mesoderm, & endoderm

All other animal groups possess ________ tissue layers composed of what?

triploblastic

• all other animal groups possess three tissue layers

• ectoderm, mesoderm, endoderm

asymmetrical

does not exhibit body symmetry

radial symmetry

any plane passing through the center of the body will result in two symmetrical halves

bilateral

All other animal groups display __________ symmetry.

bilateral symmetry

only one plane passing through the center of the body will result in two symetrical halves

body cavities

• internal fluid-filled spaces possessed by triploblastic bilateral animals

• used for nutrient & waste circulation, for cushioning of internal organs, &/or as hydrostatic skeleton

no

Do flatworms/platyhelminthes possess a body cavity?

acoelomate

condition where an organism does not possess a body cavity

yes; pseudocoelom

Do Rotifers possess a body cavity? If so, what is it called?

pseudocoelom

What kind of coelom do Nematodes have?

pseudocoelom

• a body cavity that rotifers and nematodes possess

• located between the mesoderm & endoderm

pseudocoelomate

a condition where an organisms possesses a body cavity that’s located between the mesoderm & endoderm

true coelom

All other animal groups possess a body cavity called a _____________.

true coelom

• all other animal groups possess this kind of body cavity

• located within the mesoderm

eucoelomate

condition where an organism possesses a body cavity located within the mesoderm

protostome

Flatworms, rotifers, molluscs, annelids, nematodes, arthropods

Do these triploblastic bilateral animals undergo protostome or deuterostome embryonic development?

deuterostome

Echinoderms, chordates

Do these triploblastic bilateral animals undergo protostome or deuterostome embryonic development?

protostome embryonic development

• fate of the blastospore

  • the blastospore forms the mouth first then anus second

• flatworms, rotifers, molluscs, annelids, nematodes, arthropods

• spiral cleavage - a helical arrangement of dividing cells

• determinate cleavage - all embryonic cells have a specific fate; the removal of a cell early in development will result in the death of the embryo (mosaic embryos)

• schizocelous coelom formation - the coelom forms from solid mesoderm that splits open

mouth

Does the mouth or anus form first in protostomes?

deuterostome embryonic development

• fate of the blastospore

  • the blastospore forms the anus first then mouth second

• echinoderms, chordates

• radial cleavage - a stacked arrangement of dividing cells

• indeterminate cleavage - embryonic cells have the capacity to become any cell type; the removal of a cell early in development will result in 2 viable embryos (regulative embryos)

• entercoelous coelom formation - the coelom forms from outpocketing of the endoderm and gut

anus

Does the mouth or anus form first in deuterostomes?

cleavage

• spiral or radial; determinate & ideterminate

• protostome - spiral & determinate

  • spiral - a helical arrangement of dividing cells

  • determinate - all embryonic cells have a specific fate; the removal of a cell early in development will result in the death of the embryo (mosaic embryos)

• deuterostome - radial & indeterminate

  • radial - a stacked arrangement of dividing cells

  • indeterminate - embryonic cells have the capacity to become any cell type; the removal of a cell early in development will result in 2 viable embryos (regulative embryos)

spiral & determinate cleavage

What kind of cleavage do Protostomes undergo?

radial & indeterminate cleavage

What kind of cleavage do Deuterostomes undergo?

spiral cleavage

• a helical arrangement of dividing cells

• protostomes undergo this

radial cleavage

• a stacked arrangement of dividing cells

• deuterostomes undergo this

determinate cleavage

• all embryonic cells have a specific fate

• the removal of a cell early in development will result in the death of the embryo (mosaic embryos)

• protostomes undergo this

indeterminate cleavage

• embryonic cells have the capacity to become any cell type

• the removal of a cell early in development will result in 2 viable embryos (regulative embryos)

• deuterostomes undergo this

coelom formation

• protostome- schizocelous

  • the coelom forms from solid mesoderm that splits open

• deuterostome - enterocoelous

  • the coelom forms from outpocketing of the endoderm and gut

schizocelous

Do Protostomes undergo schizocelous or enterocoelous coelom formation?

enterocoelous

Do Deuterostomes undergo schizocelous or enterocoelous coelom formation?

schizocelous coelom formation

• coelom formation

• the coelom forms from solid mesoderm that splits open

• protostomes undergo this

enterocoelous coelom formation

• coelom formation

• the coelom forms from outpocketing of the endoderm and gut

• duterostoems undergo this

embryonic development

• triploblastic bilateral animals are further differentiated based on their modes of development

  • Flatworms, rotifers, molluscs, annelids, nematodes, and arthropods undergo protostome embryonic development

  • Echinoderms and chordates undergo deuterostome embryonic development

• fate of the blastospore

  • protostome - the blastospore forms the mouth first, then anus secondly

  • deuterostome - the blastospore forms the anus first, then mouth secondly

• cleavage - spiral or radial

  • protostome - spiral cleavage

    • a helical arrangement of dividing cells

  • deuterostome - radial cleavage

    • a stacked arrangement of dividing cells

• cleavage - determinate or indeterminate

  • protostome - determinate cleavage

    • all embryonic cells have a specific fate

    • the removal of a cell early in development will result in the death of the embryo (mosaic embryo)

  • deuterostome - indeterminate cleavage

    • embryonic cells have the capacity to become any cell type

    • the removal of a cell early in development will result in two viable embryos (regulative embryos)

• coelom formation

  • protostome - schizocelous

    • the coelom forms from solid mesoderm that splits open

  • deuterostome - enterocoelous

    • the coelom forms from outpocketing of the endoderm and gut

lophotrochozoans; ecdysozoans

Protostome animals are classified as either _______________ or ________________.

lophotrochozoans

• one category protostome animals are classified under

• possesses a lophophore or a trochophore

  • lophophore - a filter feeding appendage

  • trochophore - a ciliated larval stage

lophophore

• a structure lophotrochozoans possess

• a filter feeding appendage

trochophore

• a structure lophotrochozoans possess

• a ciliated larval stage

ecdysozoans

• undergoes ecdysis

  • molting of an external nonliving cuticle (exoskeleton) in order to grow

  • crabs, shrimp, insects, arthropods

edcysis

• a process ecdysozoans undergo

• molting of an external nonliving cuticle (exoskeleton) in order to grow

precambrian animals

the sponge and cnidarian body plans evolved prior to the Cambrian explosion

Cambrian explosion

All other animal body plans (lophotrochozoan protostome, ecdysozoan protostome, deuterostome) evolved during the ________________________.