Know the difference between a n: According to the cladogram, which two species are most closely related? Some animals are asymmetrical, what are the two types of symmetry found in other animals and provide a sketch: On the animal below, label the dorsal, ventral, posterior and anterior sides.
Humans are coelomates, we have an abdomenal cavity digestive organs, some of the excretory and reproductive organs and a thoracic cavity heart and lungs.
Coelomates also form a variety of internal and external skeletons. External skeletons and coeloms appeared during the Cambrian - Ordovician time, as shown in Figure 1.
These skeletons offered several advantages to their producers: Secretion of a mineral shell that allowed the animal to use the shell as a mineral repository. Protection from drying out in the intertidal zone during low tides. Sites for anchoring muscle attachments, offering new patterns of locomotion and increased strength.
First appearances and relative diversity width of shaded area for major groups of animals. Image from Purves et al.
Clams, Scallops, and Squids Back to Top The phylum Mollusca contains overspecies with a variety of body forms and lifestyles. In mollusks, the coelom is reduced and limited to the region around the heart. The Mollusk body first appeared during the Cambrian Period.
The mantle also contributes to formation of gills or lungs. The foot is a muscular structure used for locomotion, attachment to a substrate, food capture, or a combination of functions.
A radula is an organ that bears many rows of teeth and is used for grazing on food. The nervous system consists of several ganglia connected by nerve cords.
Most mollusks have an open circulatory system: Blood diffuses back into the heart and is pumped out to the body again. Some mollusks are slow moving, and have with no head, while others are active predators that have a head and sense organs.
Figure 2 shows the hypothesized evolutionary relationships of the different groups of molluscs. Suggested evolutionary relationships of the Mollusca. They have a shell consisting of eight overlapping plates.
A ventral muscular foot is used for creeping along the substrate, or for clinging to rocks.
A chiton feeds by scraping algae and other plant food from rocks with its well-developed radula. Anatomy of chiton L. Photograph R of a chiton from http: The Class Gastropoda The class Gastropoda includes snails, terrestrial slugs, whelks, conchs, periwinkles, sea hares, and sea slugs.
Most gastropods are marinealthough some there are freshwater and terrestrial forms. Many gastropods are herbivores that use their radula to scrape food from surfaces.Echinoderm: Echinoderm, any of a variety of invertebrate marine animals belonging to the phylum Echinodermata, characterized by a hard, spiny covering or skin.
Beginning with the dawn of the Cambrian Period ( million to million years ago), echinoderms have . Review the objects listed below (many of which can be found in your lab kit). Decide what type of symmetry they possess.
Explain why you chose the type of symmetry you did. 1.
Safety Glasses 2. Petri Dish 3. Wash Bottle with Curled Straw 4. Top of a Chemical Bottle; 5. Balloon Identify which phylum each of the following organisms belongs in. The Biodiversity Heritage Library works collaboratively to make biodiversity literature openly available to the world as part of a global biodiversity community.
Clanculus aloysii is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails. 1. There are 80, species of living mollusks, classified in Gastropoda (snails and slugs), Bivalvia (clams, oysters and scallops), Cepahlopoda (squids, cuttlefish and octopuses), Scaphopoda.
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