Protists

Page
5

Slide 34

Red Algae

Red algae are reddish in color due to an accessory pigment call phycoerythrin, which masks the green of chlorophyll.

The color varies from greenish-red in shallow water to dark red or almost black in deep water. Red algae are the most abundant large algae in coastal waters of the tropics.

Red algae are usually multicellular; the largest are seaweeds.

Slide 35

Red Algae : This species has a delicate filamentous form

Bonnemaisonia

hamifera

8 mm

Slide 36

Red Algae: This leafy species is edible

Dulse (Palmaria palmata)

20 cm

Slide 37

Nori. The red alga Porphyra is the

source of a traditional Japanese food.

The seaweed is

grown on nets in

shallow coastal

waters.

The harvested

seaweed is spread

on bamboo screens

to dry.

Paper-thin, glossy sheets of nori

make a mineral-rich wrap for rice,

seafood, and vegetables in sushi.

Slide 38

Green Algae

Green algae are named for their grass-green chloroplasts.

Plants are descended from the green algae.

The two main groups are chlorophytes and charophyceans.

Most chlorophytes live in fresh water, although many are marine. Other chlorophytes live in damp soil, as symbionts in lichens, or in snow.

Chlorophytes include unicellular, colonial, and multicellular forms.

Slide 39

Green Algae

Ulva, or sea lettuce

edible seaweed

(b) Caulerpa, an

intertidal chloro-

phyte

2 cm

Slide 40

Most chlorophytes have complex life cycles with both sexual and asexual reproductive stages:

1 µm

Flagella

Cell wall

Nucleus

Cross

section of

cup-shaped

chloroplast

Mature cell

(n)

Zoospore

ASEXUAL

REPRODUCTION

Haploid (n)

Diploid (2n)

Key

Gamete

(n)

Zygote

(2n)

SEXUAL

REPRODUCTION

MEIOSIS

FERTILIZATION

+

+

–

–

Slide 41

Concept 28.6: Unikonts include protists that are closely related to fungi and animals

The supergroup Unikonta includes animals, fungi, and some protists.

This group includes two clades: the amoebozoans and the opisthokonts (animals, fungi, and related protists)

The root of the eukaryotic tree remains controversial.