1. Division of Labor
How a multicellular organism gets from single cell to millions of highly specialized cells

2. Emergent Properties
Each table should have pile of images and several statements or quotes.
The term “emergent properties” basically means that the whole is greater than the sum of the parts. Looking at the images and statements/quotes, work together to explain what “emergent properties” means in terms of the molecules, cells, tissues, etc. in our body.

3. Emergent Properties
Multicellular organisms show emergent properties. For example: cells form tissues, tissues form organs, organs form organ systems and organ systems form multicellular organisms. The idea is that the whole is greater than the composition of its parts. The cells by themselves aren’t much use. It is the many cells working as a unit that allow tissues, organs, and organisms to perform their function.
Emergence is the way complex systems and patterns arise out of a collection of relatively simple interactions.
Examples?

4. Meiosis or Mitosis?

5. Meiosis or Mitosis? Things to think about…
Is this a process of making gametes (sex cells)? Or do some of these cells become something other than gametes?
Do all of these cells contain the same genetic information?

6. Meiosis or Mitosis?
How do we go from gametes to a “full-fledged” organism?
Fertilization (egg + sperm meet) = zygote.
Many rounds of cell division (we do need more than one cell to perform all our many functions, after all!). This cell division is called MITOSIS.
Cells become specialized.

7. Egg + Sperm…
Let’s watch what happens…

8. Early stages of embryogenesis
Zygote: single fertilized egg to ball of less than 16 cells.
Morula: dense ball of (at least) 16 cells.
Blastula: hollow ball of cells.
Blastocyst
Gastrula: hollow ball of cells with different “cavities” inside.
Neurula: “ with neural tube. ….

9. Early stages of embryogenesis
Blastocyst (follows blastula stage in mammals): Hollow ball of cells with “inner cell mass.”
Trophoblast: outer layer cells of blastocyst that become the placenta in mammals.
Inner cell mass core of cells inside trophoblast; becomes the fetus.

10. What’s next?
What needs to happen to get from this…
To this?

11. Take a moment… Think of any type of organism.
When you thought of any kind of organism, you probably visualized it in your head, right? Without telling us what you visualized, can I have a volunteer to draw your type of organism using the Mobi? Have at least 2 students draw their type of organism using the Mobi device. Have the class guess what type of organism each student drew.
Student’s name drew an image of a horse. What if instead his image looked like this (teacher draws a distorted image of a horse using Mobi)? If you saw this image, would you say to me that it is a horse? (students should say “no)

12. Organisms are defined in part by their shape
Morphology: the form and structure of an organism.
_____________: The process of forming the shape and structure of an organism and its parts.
So we can agree that all organisms have a particular shape, or morphology. This is true no matter what type of organism you are discussing.
As organisms develop, their shape also develops. If the root –genesis means “creation of,” what do you think we could call the process of the creation of an organism’s shape? (Morphogenesis)
Morphogenesis is a regulated process in all organisms. Just take a look at humans. Unless something goes wrong during morphogenesis, we always develop with two eyes on the front of our face. But how come our eyes are located on our face, and we don’t have eyes on the tips of our hands and feet like a starfish?

13. Organisms are defined in part by their shape
Morphology: the form and structure of an organism.
Morphogenesis: The process of forming the shape and structure of an organism and its parts.
So we can agree that all organisms have a particular shape, or morphology. This is true no matter what type of organism you are discussing.
As organisms develop, their shape also develops. If the root –genesis means “creation of,” what do you think we could call the process of the creation of an organism’s shape? (Morphogenesis)
Morphogenesis is a regulated process in all organisms. Just take a look at humans. Unless something goes wrong during morphogenesis, we always develop with two eyes on the front of our face. But how come our eyes are located on our face, and we don’t have eyes on the tips of our hands and feet like a starfish?

14. Morphogenesis in the context of embryology
Egg to fetus

15. What determines morphology?
Morphogenesis is controlled at the cellular level, in large part due to the process called cell differentiation. Cell differentiation refers to a cell taking on its mature form and role for an organism.
About 7 weeks post-conception
About 12 weeks post-conception

16. What determines morphology?
Morphogenesis is controlled by a process called cell differentiation.
Morphogenesis is controlled at the cellular level, in large part due to the process called cell differentiation. Cell differentiation refers to a cell taking on its mature form and role for an organism.

17. What determines morphology?
Morphogenesis is controlled by a process called cell differentiation.
What do you think “cell differentiation” means?
Think - Pair - Share
Morphogenesis is controlled at the cellular level, in large part due to the process called cell differentiation. Cell differentiation refers to a cell taking on its mature form and role for an organism.

18. What determines morphology?
Morphogenesis is controlled by a process called cell differentiation.
Cell differentiation: process of a cell taking on its mature form and role for an organism.
A cell becomes differentiated by producing specific proteins from the DNA template that allow it to develop into its mature form.
Differentiation results in cells taking on their mature form and function, which are all related to that cell’s structure.
Morphogenesis is controlled at the cellular level, in large part due to the process called cell differentiation. Cell differentiation refers to a cell taking on its mature form and role for an organism.

19. Cell Morphology (Shape)
Cell Differentiation
Morphogenesis
If morphogenesis controls the development of the shape of organisms, and cell differentiation greatly affects morphogenesis, what processes control cell differentiation?
Cells receive signals from their internal and external environment that affect what genes in their DNA are turned on and what genes are turned off at specific times. A cell’s communication with its environment, followed by the SELECTIVE transcription of genes, allows cells to differentiate, and organisms to develop.

20. Cell Signaling
In order to differentiate, cells must somehow “talk” with each other to decide which cells become what.

21. Apoptosis: Example of Cell Signaling
Apoptosis: Programmed cell death
Controlled by cell signals
Extracellularly: hormones
Intracellularly: due to cell stress, such as binding of nuclear receptors by viruses.
Important for morphology of organism… can you think why this might be?

22. Apoptosis: Example of Cell Signaling
Apoptosis: Programmed cell death
Controlled by cell signals
Extracellularly: hormones
Intracellularly: due to cell stress, such as binding of nuclear receptors by viruses.
Important for morphology of organism… can you think why this might be?
Think - Pair - Share

23. Apoptosis About 7 weeks post-conception About 12 weeks post-conception
Morphogenesis is controlled at the cellular level, in large part due to the process called cell differentiation. Cell differentiation refers to a cell taking on its mature form and role for an organism.
About 7 weeks post-conception
About 12 weeks post-conception

24. Induction Induction: the initiation or cause of a change/process
Happens via cell communication (cell signaling)
Results in different genes being turned on or off.

25. Regulatory Cascades SIGNAL Gene 1 Gene 2 Gene 3
Gene 1 activates expression of Gene 2
Gene 2
Gene 2 activates expression of Gene 3
Genes that control development are organized into hierarchical regulatory cascades
And so on…
Gene 3

26. Cell Differentiation
Cells in a developing embryo begin to differentiate when they are induced to do so by various signals.

27. Genes and function Chromosome Gene Intron Exon Protein Gene regulation
Differentiation
Morphogenesis

28. Example of induction and differentiation at work!
The pressing question… meiosis or mitosis?

29. Meiosis or Mitosis?
How do we go from gametes to a “full-fledged” organism?
Fertilization (egg + sperm meet) = zygote.
Many rounds of cell division (we do need more than one cell to perform all our many functions, after all!). This cell division is called MITOSIS.
Cells become specialized.

30. Meiosis or Mitosis?
How do we go from gametes to a “full-fledged” organism?
Fertilization (egg + sperm meet) = zygote.
Many rounds of cell division (we do need more than one cell to perform all our many functions, after all!). This cell division is called MITOSIS.
Cells become specialized.

31. Meiosis or Mitosis?
How do we go from gametes to a “full-fledged” organism?
Fertilization (egg + sperm meet) = zygote.
Many rounds of cell division (we do need more than one cell to perform all our many functions, after all!). This cell division is called MITOSIS.
Cells become specialized.
Note: Up through the BLASTULA stage, cells are UNDIFFERENTIATED
Write this down!!!

32. How do “sex cells” become “sex cells?”
A germ cell is a cell that gives rise to sex cells. The very first germ cells are called “primordial germ cells” and are initially located outside of the sex organs. (Primordial means “original” or “the first”).
Migrate to sex organs. Divide while migrating.
Primordial germ cells
Germ cells
Meiosis
(diploid)
(diploid)
Gametes
(haploid)

33. How do “sex cells” become “sex cells?”
Primordial germ cells originate near the cells in the developing embryo that eventually become the gut.
Endoderm (gut)

34. How do “sex cells” become “sex cells?”
What determines which cells become primordial germ cells in the early embryo?
Asymmetrical cell division (in animals other than mammals and birds)
Induction by neighboring cells (in mammals and birds)

35. How do “sex cells” become “sex cells?”
1. Asymmetric cell division
= “sex cell molecule”

36. How do “sex cells” become “sex cells?”
1. Induction by neighboring cells

37. How do “sex cells” become “sex cells?”
1. Induction by neighboring cells
Hey, you guys. Become a sex cell!

38. An Example of Genetic Control of Differentiation
Forelimb becomes wing, hindlimb becomes leg (in chick)
Forelimb is allowed to develop just forward of expression domain of Hox gene Hoxc6
Where have overlap bt the two, everything knows I am in trunk region, make ribs not limbs
In snake, expression domain of the two hox genes have become greatly elongated, have coexpression of elongated thorax telling make a rib make a rib make a rib, don’t make legs

39. Your table has been given a description of a cell type.
Next to the cell type, write the function of that cell and any special structures and shapes (morphology) or organelles that cell might need in order to function the way it does.
How does this morphology relate to the function of the cell?
What genes need to be turned on in this cell?

40. Type of cell
Function
Morphology
Genes
Velcro cell
Sticks to objects; holds objects together and prevents them from separating
Cell membrane contains interlocking components
Genes turned on for making interlocking cell membrane proteins; proteins that provide strength and flexibility to interlocking cell membrane

41. Your table has been given a description of a cell type.
Next to the cell type, write the function of that cell and any special structures and shapes (morphology) or organelles that cell might need in order to function the way it does.
How does this morphology relate to the function of the cell?
What genes need to be turned on in this cell?