Suggestions / Requests

Suggested by Charity : Frog Metamorphosis

The top-left picture shows an adult frog, if you follow the pictures around clockwise, this is the typical lifecycle of a frog (note that these are not all the same species). If you don't want to read this all, then here's a fun video to watch:

(Top-center picture): In the Spring, female frogs lay batches of gelatinous eggs (called "frogspawn"). Frogspawn can be laid in water, or on land as long as the air is humid enough to prevent desiccation (drying out).

(Top-right picture): The eggs that started off as a black speck in the core, have begun to develop into tadpoles.

(Bottom-right picture): Approximately one week after fertilization of the eggs, tadpoles will have developed and hatched. Tadpoles differ from adult frogs in several important ways: Tadpoles have a tail, no limbs (early on), and instead of lungs, tadpoles have external gills (covered in a gill sac).

(Bottom-center picture): After 6-9 weeks, tadpoles develop hind legs, and their gills are replaced by lungs! As a result, they must swim at the water's surface to breathe (no more gills to filter oxygen out of the water).

(Bottom-right picture): Forelegs begin to develop, the tadpole is now called a "froglet" (or in the case of toads, a "toadlet"). Shortly after forelegs develop, the tail will begin to disappear.

(Top-right picture): Metamorphosis is complete - the product is an adult frog complete with lungs, legs, and lacking a tail. After about 3 years, adult frogs attain the ability to reproduce.

You might be wondering what dictates the transformation from one stage to another? Well, thyroid hormones work together to speed-up, or slow-down the rate of development. These hormones respond to the environmental conditions, so if food or temperature are not right, the hormones can slow-down metamorphosis. On the other hand, if the environment is suitable, hormones will speed up development.

Last thing I want to say, is just an interesting fact: Not all frogs go through a tadpole stage. An example is the common coqui, which lacks a tadpole stage, and instead, hatches from an egg as a froglet.

    Suggested by Jesse: Venus Flytrap

Most, if not all of us have heard of the infamous Venus flytrap (Dionaea muscipula). It is only one species of carnivorous plants, out of a total of over 600!

Although there is only one species of Venus flytrap, horticulturists have developed many cultivars (varieties) of the species. Some venus flytrap cultivars can be seen in the photos on the left. They can have varied trap sizes, trap positions (vertical, horizontal), colours (all red, all green, mixed), and varying cilia lengths (cilia are the teeth projecting from the trap's rim).

So, we all know WHAT the Venus flytrap does, but HOW does it do it? The following video explains if very nicely:

  

If you want more detail on the trap's operating mechanism the following link goes into more cellular detail:

http://www.botany.org/carnivorous_plants/venus_flytrap.php

Venus flytraps don't only eat flies, though. Larger insects, spiders, and even frogs have been observed to be trapped within a Venus flytrap (see photo - this frog was lucky enough to escape). Venus flytraps are so successful at what they do, that there are even marine organisms that mimic its design! For instance, the Venus flytrap anemones (bottom-right photo) have "molecular blueprints" that are comparable to those of the Venus flytrap.