Development Links - Biology. Components of Development Growth - The process of a multicellular...
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Transcript of Development Links - Biology. Components of Development Growth - The process of a multicellular...
DevelopmentDevelopment
Links - BiologyLinks - Biology
Components of Components of DevelopmentDevelopment
GrowthGrowth- The process of a - The process of a multicellular increasing its number of multicellular increasing its number of cells, becoming larger. (i.e. zygote to cells, becoming larger. (i.e. zygote to an adult) an adult)
DifferentiationDifferentiation- The process of - The process of cells in a multicellular organism cells in a multicellular organism (initially all alike) becoming different (initially all alike) becoming different from each other generating the from each other generating the various tissues (i.e. nerve, muscle, various tissues (i.e. nerve, muscle, skin and bone, etc.) necessary to be a skin and bone, etc.) necessary to be a functional adult .functional adult .
Thoughts on development:Thoughts on development:GrowthGrowth
Cells generating more cells (Mitosis and Cells generating more cells (Mitosis and Cytokinesis)Cytokinesis)
A single cell has size limits, therefore for A single cell has size limits, therefore for organisms to become larger they must be organisms to become larger they must be multicellular.multicellular.
All cells of an organism have a complete All cells of an organism have a complete set of DNA to make the entire organism.set of DNA to make the entire organism.
Cell death, as well as cell growth must Cell death, as well as cell growth must occur for proper developmentoccur for proper development
Connected to the cell cycle.Connected to the cell cycle.
Mitosis and CytokinesisMitosis and Cytokinesis
Cell cycleCell cycle
Phases of MitosisPhases of Mitosis InterphaseInterphase ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase
Animation link(s)Animation link(s)
http://science.nhmccd.edu/biol/mitosis/pmitosis.htmlhttp://science.nhmccd.edu/biol/mitosis/pmitosis.html
http://www.lewport.wnyric.org/jwanamaker/animations/http://www.lewport.wnyric.org/jwanamaker/animations/mitosis.htmlmitosis.html
http://www.sci.sdsu.edu/multimedia/mitosis/mitosis_qt1http://www.sci.sdsu.edu/multimedia/mitosis/mitosis_qt1.html.html
InterphaseInterphase
ProphaseProphase
MetaphaseMetaphase
AnaphaseAnaphase
TelophaseTelophase
Thoughts on development:Thoughts on development:DifferentiationDifferentiation
What if your entire body was made of only What if your entire body was made of only stem cells? Muscle cells? Nerve cells?stem cells? Muscle cells? Nerve cells?
Do different types of cells (tissue) perform Do different types of cells (tissue) perform different jobs in a multicellular organism?different jobs in a multicellular organism?
If all of the organisms cells are genetically If all of the organisms cells are genetically Identical, how do they become different Identical, how do they become different types of cells (tissue)?types of cells (tissue)?
Epithelial and ConnectiveEpithelial and Connective
Nerve and MuscleNerve and Muscle
OKAY???????OKAY???????
But how does an But how does an organism get all of organism get all of these cell (tissue) these cell (tissue)
types?types?
Historical perspectiveHistorical perspective
The “Homunculus” Theory The “Homunculus” Theory = A fully formed = A fully formed person, just very tiny, person, just very tiny, exists in the head of a exists in the head of a sperm cell. The egg sperm cell. The egg makes no contribution makes no contribution except to function as except to function as an incubator.an incubator.
No differentiation No differentiation necessary!!!!!!!!!! necessary!!!!!!!!!!
We now know better.We now know better.
Embryonic differentiation:Embryonic differentiation:ZygotesZygotes
Early embryonic Early embryonic developmentdevelopment
BlastulaBlastula
GastrulationGastrulation
It is not birth, marriage, It is not birth, marriage, or death, but or death, but
gastrulation, which is gastrulation, which is truly the most important truly the most important
time in your life."time in your life."
Lewis Wolpert (1986) Lewis Wolpert (1986)
Embryonic cell (tissue) Embryonic cell (tissue) typestypes
As embryo’s As embryo’s develop to the develop to the gastrulation gastrulation stage they form stage they form three basic three basic types of tissue types of tissue which which differentiate into differentiate into all other tissues:all other tissues:
EndodermEndoderm MesodermMesoderm EctodermEctoderm
These basic tissues become:These basic tissues become:
OKAY ??OKAY ??
But how do we get to But how do we get to become these tissues become these tissues from embryonic stem from embryonic stem
cells?cells?
Influences on differentiationInfluences on differentiation(switching genes on and off)(switching genes on and off)
Environmental influences both inside the cell and Environmental influences both inside the cell and outside the cell can cause certain genes to switch outside the cell can cause certain genes to switch on or off at appropriate or inappropriate times.on or off at appropriate or inappropriate times.
Inside the cell- differential distribution of materials Inside the cell- differential distribution of materials during cell division can cause cells to develop during cell division can cause cells to develop differently.differently.
Outside the cell- chemical communication with Outside the cell- chemical communication with nearby cells may influence development based on nearby cells may influence development based on strength of signal.strength of signal.
Induction- is a special type of outside influence. Induction- is a special type of outside influence. (Leads to Cell Differentiation)(Leads to Cell Differentiation)
??????????? (good field for a career)??????????? (good field for a career)
Induction!!!Induction!!!
ApoptosisApoptosis (cell death) at the (cell death) at the appropriate time is also very vital to appropriate time is also very vital to
development.development.
What next?What next?
Development sometimes messes Development sometimes messes up!up!
CancerCancer- one’s own cells fail to - one’s own cells fail to stop reproducing when they stop reproducing when they should.should.
Birth defects-Birth defects- environmental environmental factors + genetics cause factors + genetics cause misinformation during misinformation during development.development.
Key Development termsKey Development terms ZygoteZygote BlastulaBlastula GastrulationGastrulation GrowthGrowth CytokinesisCytokinesis MitosisMitosis
interphaseinterphase
prophaseprophase
metaphasemetaphase
anaphaseanaphase
telophasetelophase
DifferentiationDifferentiation SenescenceSenescence Cell cycleCell cycle DNADNA InductionInduction CancerCancer MetastasisMetastasis Birth defectsBirth defects MutationMutation
Final thoughts Final thoughts Development must occur at the correct times and Development must occur at the correct times and
correct places in the embryo.correct places in the embryo. Animal development occurs in consistent Animal development occurs in consistent
patterns.patterns. Plants go through similar development.Plants go through similar development. Cell deaths must also occur at appropriate times.Cell deaths must also occur at appropriate times. Development is a zygote to death process.Development is a zygote to death process. Developmental errors often cause spontaneous Developmental errors often cause spontaneous
abortions (miscarriage) abortions (miscarriage) Environmental factors can greatly influence Environmental factors can greatly influence
development (especially during very early development (especially during very early development).development).
Development = growth + differentiation.Development = growth + differentiation. We still have a lot to learn about development.We still have a lot to learn about development.