Life Photo Meme: Edible

Kingdom: Protista

Phylum: Phaeophyta

Class: Phaeophyceae

Order: Laminariales

Family: Lessoniaceae

Here we have some giant kelp, Macrocystis pyrifera. While not very tasty by itself (to my mind), brown alga such as the giant kelp contain algin. Algin is often used as a thickening agent in many foods such as puddings, ice cream, icing, candies, as well as some beauty products. If you have a thick and creamy food item, check the ingredients and chances are algin or carrageenan (from red algae) is present. While algin may help add to our waistline by being in such yummy foods, a second compound, fucoxanthin may promote weight loss [1, 2].

Life photo meme: Green algae

Kingdom: Protozoa

Phylum: Chlorophyta

Class: Ulvophyceae

Order: Ulvales

Family: Ulvaceae

I've posted this photo before, and talked about the encrusting organisms that live on it. Today I want to focus on the substratum itself, the green algae Ulva. Belonging to the phylum Chlorophyta, or the green algae, this group is considered the basal group for land plants. They share the same chlorophyll pigments, store starch, and posses cellulose cell walls.

Ulva is an interesting algae, it grows in large sheet-like patches only two cells thick. The sheets are often ruffled and fluted making its common name, sea lettuce, an apt descriptor. It attaches to rocks, docks, and other structures by a very small disk.

It also has a very interesting life cycle termed alternation of generations. The diploid generation makes spores which grow into a haploid adult without fertilization. The halpoid adult (n) makes gametes which are fertilized and grow into a diploid adult (2n). Repeat the cycle. There are lots of algae that have this type of life cycle, but Ulva is one of the only ones where you cannot tell if the adult is haploid or diploid by looking at it.

(Click here for full size image)