LEVELS OF ORGANIZATION Chapter 11 Lesson 2

Essential Questions How do unicellular and multicellular organisms differ? How does cell differentiation lead to the organization within a multicellular organism?

New Vocabulary Cell differentiation Stem cell Tissue Organ Organ system

Unicellular vs. Multicellular Organisms Unicellular - Carry out all life processes (they have all 6 characteristics of life)  Prokaryotes  Eukaryotes  What’s the difference between them? Multicellular – made of many types of eukaryotic cells working together, each with a specialized function.

Prokaryotes

Multicellular Organisms All multicellular organisms come from one cell: a fertilized egg (AKA zygote) These cells become different as the zygote develops through mitotic cell division  Cell differentiation – the process by which cells become different types of cells Stem cells – unspecialized animal cells that are able to develop into many different cell types What does it mean for a cell to differentiate? How do unicellular and multicellular organisms differ? What advantages does a multicellular organism have over a unicellular organism? What makes stem cells different from other cells? How could adult stem cells be useful in treating different conditions?

Cell differentiation What is the difference between an egg and a fertilized egg? Are all the cells types that a fertilized egg develops into shown here? Why?

Multicellular Organisms Plants have unspecialized cells similar to stem cells.  These are grouped in areas of a plant called meristems  Found in roots and stems What is a meristem? What do plant meristems produce? What part of roots and stems contain meristems? Why do you think this is true?

Multicellular Organisms Tissues – groups of similar types of cells in multicellular organisms that work together to carry out specific tasks.  4 main types of animal tissue  Muscle  Connective  Nervous  Epithelial  3 main types of plant tissue  Dermal  Vascular  Ground tissue What are the four types of animal tissue and their functions? What are the three types of plant tissue and their functions? Compare animal and plant tissues.

Animal Tissue

Plant Tissue

Multicellular Organisms Organs – groups of different tissues working together to perform a particular job Organ systems – groups of different organs that work together to complete a series of tasks.  Multicellular organisms usually have many organ systems that work together to carry out all the jobs needed for the survival of the organism. What is a tissue? What is an organ? What is an organ system? Vascular tissue in plants performs a function similar to which organ system in the human body? What are some major organs in plants?

Multicellular Organisms What is an organism? How does cell differentiation lead to the organization within a multicellular organism? How do the nervous system and the muscular system work together in a human? Why is this important?

Review What is the process by which cells become specialized? A. Photosynthesis B. Vascular development C. Prokaryotic process D. Cell differentiation

Review What are the unspecialized animal cells capable of developing into many different cell types? A. Fibers B. Stem cells C. Meristems D. Tissues

Review What is the term for groups of different organs that work together to complete a series of tasks? A. Tissues B. Organisms C. Organ systems D. Stem cells