RhodophytaThey are also known as red

algae or rhodophytes.They are multicellular

organisms. Characterized by

photosynthetic pigments such as phycoerythrin, phycocyanin and allophycocyanins, and the absence of flagella and centrioles.

They don’t have chloroplast endoplasmic reticulum.

Characterized by their branching. They are able to thrive at deeper

depths of the ocean compared to other algae.

They are mostly found along the coastal and continental shelf areas of tropical, temperate and cold-water regions.

It consists of approximately 5000 genera and 5000 species.

It is one of the most ancient eukaryotes, with fossils that date back to the mid-proterozoic.

Store sugars as glycogen or Floridean starch A long chain of glucose

sugars with lots of side branches.

Structures

Red, algal cell wall– An inner layer with cellulose.– Gelatinous outer layer.– Contain amorphous mucilages

(shapeless mucuses). Nuclei Chloroplasts

– Contain phycobilins, chlorophyll a, carotenes, xanthophylls.

Phycobilisomes– Involved in photosynthesis

Spermatangia– Male reproductive organ, filled

with spermatia (male reproductive cell).

Carpogonium– Female reproductive organ.

Trichogyne– Hair like receptor of the

carpogonium. Cytoplasm– Forms floridean starch

Open protoplasmic connection— connects daughter

cells. Pitplug

— closes the connection between 2 daughter cells.

Reproduction

Reproduce both sexually and asexually.

The spermatium relies on water to reach the carpogonium.

It makes contact with trichogyne and its nucleus merges with that of the carpogonium.

The carpogonium forms a large bulb, which separates and becomes young red algae.

Nutrition

They obtain energy through photosynthesis.

Some rhodophytes were found to be parasitic in nature.

Ecology

Most are found in marine ecosystems, while a few are found in freshwater.

They live attached to surfaces.

They harness light efficiently, which enables them to live at great depths.

Coralline red alga is essential in marine ecosystems because they are reef-building organisms. They produce calcium

carbonate in their cell walls.

Some red algae have been found to be parasitic

Some transport nutrients from their host through a haustoria.

Some transfer their nuclei into the host plant and hijack the host.

Examples

Porphyra tenera It is also known as nori.Small, red alga.They have crinkled edges

and are able to reach a width of 20 cm.

They are irregularly shaped, leaf-like and membranous.

Appear green in their early stages.

Appear brownish-purple or purple-red in maturity.

They live on exposed coasts and are attached to rocks or mollusks.

They can also be found in the midtidal to splash zone.

They are most abundant in temperatures between 4-9 °C

They are often found attached to rocks or mollusk shells. It is abundant especially on exposed coasts.

The calcium carbonate within its cell walls strengthens its structure and causes it to appear pink. This substance also protects them from being eaten by shore grazers.

Serve as a home for small organisms which eat the microorganisms living on it.

Corallina officinalisMarine species, also known as coral

weed.

Whitish-pink to lilac in color.

Its calcified, branching and segmented fronds reach up to 12 cm in length from a crustose, disk shaped root.

Urn-shaped reproductive organs.

60-70 mm high

Galaxaura spp.Tubular thicket algae.Heavily calcified and forms

hemispherical domes, up to 15 cm, attached by a single holdfast or root.

Its segments branch out dichotomously.

Its segments are tubular in shape, smooth, and hard with flexible joints

The tips of its branches have a central hole.

They are redish to orange and off-white in color.

They are most commonly found attached to rocks or rocky surfaces.

Sources• http://www.ehow.com/how-does_4574307_algae-reproduce.html• http://lifeofplant.blogspot.com/2011/01/red-algae.html• http://marinelife.about.com/od/plants/p/redalgae.htm• http://www.microscopy-uk.org.uk/mag/indexmag.html?http://ww

w.microscopy-uk.org.uk/mag/artmar99/red.html• http://university.uog.edu/botany/Plant_Di/rhodophyta.htm• http://www.algaebase.org/search/species/detail/?species_id=107• http://www.marlin.ac.uk/speciesinformation.php?speciesID=3039• http://porphyra.wetpaint.com/• http://www.fao.org/fishery/species/2790/en