early development selected invertebrates. cleavage what characterizes this process? what...

Early Development Early Development

Selected InvertebratesSelected Invertebrates

CleavageCleavage

What characterizes this process?What characterizes this process?

CleavageCleavage

How does the cell cycle of blastomeres How does the cell cycle of blastomeres compare with that of somatic cells?compare with that of somatic cells?

CleavageCleavage

What happens to the embryo during What happens to the embryo during the mid-blastula transition?the mid-blastula transition?

When does this occur?When does this occur?

CleavageCleavage

What is karyokinesis and cytokinesis and What is karyokinesis and cytokinesis and how do they compare?how do they compare?

CleavageCleavage

What influences the pattern of What influences the pattern of cleavage in a particular organism?cleavage in a particular organism?

CleavageCleavage

CleavageCleavage

How are cell fates specified during How are cell fates specified during cleavage?cleavage?– cell-cell interactionscell-cell interactions– asymmetric distribution of morphogenic asymmetric distribution of morphogenic

determinantsdeterminants

GastrulationGastrulation

What characterizes gastrulation in What characterizes gastrulation in organisms?organisms?

What kinds of movements occur?What kinds of movements occur?

Axis FormationAxis Formation

What are the three major body axes?What are the three major body axes?

Sea Urchin DevelopmentSea Urchin Development

What does the cleavage pattern look like?What does the cleavage pattern look like?


What characterizes the blastula stage?What characterizes the blastula stage?


At what stage are the fates of individual At what stage are the fates of individual cells determined?cells determined?


What role does What role does ββ--catenin play in catenin play in specification?specification?


When does axis specification occur?When does axis specification occur?– animal-vegetal axis established before animal-vegetal axis established before

fertilizationfertilization– anterior-posterior axis determined by a-anterior-posterior axis determined by a-

v axisv axis vegetal – determinants for posterior vegetal – determinants for posterior

developmentdevelopment

– dorsal-ventral and left-right after dorsal-ventral and left-right after fertilizationfertilization d-v by first cleavage planed-v by first cleavage plane


How does How does gastrulation begin?gastrulation begin?


What appears to be responsible for the What appears to be responsible for the ingression of primary mesenchyme?ingression of primary mesenchyme?


What appears to be responsible for the initial What appears to be responsible for the initial invagination that occurs during gastrulation?invagination that occurs during gastrulation?


What is the fate of these vegetal plate cells?


What happens during later stages of What happens during later stages of invagination?invagination?

Snail DevelopmentSnail Development

What kind of cleavage pattern What kind of cleavage pattern characterizes these animals?characterizes these animals?


Orientation of Orientation of cleavage plane cleavage plane determines right or determines right or left coiling snailsleft coiling snails


What appears to be responsible for the What appears to be responsible for the mosaic development seen in molluscs?mosaic development seen in molluscs?

Snail DevelopmentSnail Development What is the polar lobe and why is it important?What is the polar lobe and why is it important?


Why does removal of the D blastomere Why does removal of the D blastomere or its first or second derivatives result in or its first or second derivatives result in incomplete larvae?incomplete larvae?

If D blastomeres don’t directly If D blastomeres don’t directly contribute cells to formation of many contribute cells to formation of many structures why are they so important to structures why are they so important to the formation of the same structures?the formation of the same structures?


What other aspect of snail What other aspect of snail development does the polar lobe development does the polar lobe influence?influence?– How do we know this to be true?How do we know this to be true?


How does gastrulation take place in snails?How does gastrulation take place in snails?

Tunicate DevelopmentTunicate Development

What makes these What makes these organisms rather organisms rather unique?unique?

What type of What type of cleavage pattern cleavage pattern do they have?do they have?


In what way does the pigmentation in In what way does the pigmentation in Styela partita Styela partita provide developmental provide developmental information?information?


What evidence is there of What evidence is there of autonomous specification in tunicate autonomous specification in tunicate blastomeres?blastomeres?– transplant experimentstransplant experiments– RNA hybridization experimentsRNA hybridization experiments– altering altering ββ-catenin levels in cells-catenin levels in cells


What evidence is there for What evidence is there for conditional specifiction?conditional specifiction?– BMP signal from endoderm induces BMP signal from endoderm induces

anterior cell to become notocordanterior cell to become notocord works through activation of works through activation of Brachury Brachury genegene

– FGF signal induces posterior cell to FGF signal induces posterior cell to become mesenchymebecome mesenchyme


When are the When are the embryonic axes embryonic axes established?established?– dorsal-ventral – dorsal-ventral –

prior to first prior to first cleavagecleavage

– anterior-posterior – anterior-posterior – prior to first prior to first cleavagecleavage

– left-right – first left-right – first cleavagecleavage

Tunicate Development Tunicate Development

What is What is gastrulation like in gastrulation like in these organisms?these organisms?

Caenorhabditis elegansCaenorhabditis elegans

What does What does C. elegansC. elegans look like? look like?

C. elegansC. elegans

What pattern of cleavage in seen in this What pattern of cleavage in seen in this nematode?nematode?


What determines What determines anterior-posterior anterior-posterior axis?axis?

What is the What is the importance of the importance of the P-granules?P-granules?


When is dorsal-ventral and left-right axes When is dorsal-ventral and left-right axes established?established?


In what way is autonomous In what way is autonomous specification demonstrated in this specification demonstrated in this organism?organism?– P1 develops without presence of AB cellP1 develops without presence of AB cell

In what way is conditional In what way is conditional specification demonstrated?specification demonstrated?– AB cell requires cell-cell interactionsAB cell requires cell-cell interactions– EMS requires signal from P2EMS requires signal from P2


cell-cell signalingcell-cell signaling


Where in this organism is Where in this organism is autonomous and conditional autonomous and conditional specification integrated?specification integrated?


When does When does gastrulation begin gastrulation begin in this organism?in this organism?

early development selected invertebrates. cleavage what characterizes this process? what...

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