Red and green algae

1
Red and green algae

• The primary endosymbiotic lineages

2
Red algae (Rhodophyta)

• Oldest multicellular eukaryotes
• Complex life cycles
• Important in ________ systems

Includes Porphyra (nori)
3
The green algae (gt7,000 spp.)

• Share with land plants
• ______ pectins cell wall
• plastids with 2 membranes
• chlorophyll a and b
• starch storage
• similar stellate flagella base
• Land plants are a branch of the green algae

4
green algal clade
Land plants
charophytes
Other green algae
Land plants are a ______ of the green algae Most
closely related to charophytes
5
Charophytes

• __________
• Non-monophyletic unless one includes the land
  plants
• Cell division with a persistent spindle and a
  phragmoplast
• Zygotic meiosis and oogamy

6
Cell division in other green algae

• Original _______ breaks down
• The nuclei are separated by a phycoplast of
  equatorial microtubles

7
Cell division in charophytes

• _______ persists
• Small vacuoles aggregate between nuclei (form the
  phragmoplast)
• The cell plate is formed in the phragmoplast

8
The basic sexual cycle
Zygote
2n
2n
2n
Mitosis
2n
2n
2n
2n
2n
2n
2n
Syngamy
Gametes
n
n
Meiosis
n
n
n
n
n
n
n
Mitosis
Spores
n
n
n
9
Zygotic meiosis
Zygote
2n
Syngamy
Gametes
n
n
Meiosis
n
n
n
n
n
n
n
Mitosis
Spores
n
n
n
10
Basic sexual cycle
How has this been modified in animals?
Zygote
2n
2n
2n
Mitosis
2n
2n
2n
2n
2n
2n
2n
Syngamy
Gametes
n
n
Meiosis
n
n
n
n
n
n
n
Mitosis
n
n
n
11
How has this been modified in animals?
Zygote
2n
2n
2n
Mitosis
2n
2n
2n
2n
2n
2n
2n
Syngamy
Gametes
n
n
Meiosis
12
Types of gamete production
-

________
Anisogamy
Oogamy
13
Zygotic meiosis (oogamy)
Zygote
2n
Syngamy
Egg
Sperm
n
Meiosis
n
n
n
n
n
n
n
n
Mitosis
n
n
n
14
Features shared by land plants share and some
charophytes

• Phragmoplast/Plasmodesmata
• Oogamy
• Retained zygote (in Coleochaete)
• ________ (protects spores)

15
What features of the aquatic green algae suggest
a close affinity with land plants?

• Plastids with four membranes
• Some green algae form lichens
• Some green algae make a phragmoplast during cell
  division
• Green algae are mainly marine
• Green algae occur on land