Plant Evolution

“If you are not a microbe and not animal, then you are most likely a

plant”

-Biology4kids.com

Actual Plant Evolution

• Closest Common Ancestor to Plants:Multicellular Algae

Protist Evolution:-Heterotrophic (Amoeba)-Unicellular and Autotrophic (Euglena/Diatoms)-Multicellular and Autotrophic (Typical Algae)

• So if Algae can be multicellular, what makes it a plant?– Apical Meristem

promotes growth

– Multicellular Embryo

– Alternation of Generations

Evolution of a Multicellular Embryo

Protists--Very Diverse!

Evolution of Eukaryotic Cells

• Endosymbiosis– Evidence:

• DNA

• Reproduce by Binary Fission

• Size

• Double Membranes

Endosymbiosis

What do Charophycean algae and plants have in common?

• Homologous chloroplasts (they are green!)

• Cellulose Cell Walls

• Peroxisomes

• Homologous Sperm

• Molecular similarities (DNA)

Evolution of Main Groups of Plants

On your own

• Review:– Alternation of Generations– Reproductive Tissues

Plant Organization

• Organs

• Tissues

• Cells

Let’s look at some of the plant basics…

• In plants, there are three major types of organs:– Leaves

– Roots

– Shoots

• Note details in diagram about roots and shoots

Modified Roots and Shoots

Modified Leaves

good things come in threes

• In plants, there are three types of tissues:

• Dermal– Cuticle--adaptation

• Vascular– Xylem & Phloem

• Ground– Key Functions

In plants, there are three types of cells

• Parenchyma - think “parent” (along with metabolic functions)

• Collenchyma - weak walls, growth

• Sclerenchyma -thick walls, support, DEAD

Details of a Leaf

• Look at the leaf as an organ and identify tissue and cell types.

Unity and Diversity: Angiosperms

Observations and Analysis in Lab notebooks

Introduction—What is the role of the leaf and how is it organized to perform the function of photosynthesis.

Observations and Analysis--

1.Wet mount of stomata. Label guard cells and identify purpose of stomatat.2.Prepared leaf slide. Label and provide purpose of each tissue type.

Label: Epidermis (collenchyma), cuticle, mesophyll, palisade parencyhma, spongy parenchyma, vascular bundle (schlerenchyma)

3.Monocot and Dicot stemCompare and contrast the vascular tissue and be able to recognize the

difference.

Then make a chart in your lab notebook showing the 5 major differences between monocots and dicots.

Conclusion: Describe how the organization of a leaf allows for the emergence of the funciton of photosynthesis.

Additional Resources on Plant Diversity

• Book: Chapter 35-38; Chapter 28-30

• Private Life of Plants: Putting Down Roots ???When???Friday:

Photosynthesis: Chapter 10