Invertebrate Classification Quiz

Two distinct categories of animal body symmetry include bilateral symmetry, such as that seen in crustaceans, with a right and left side that are mirror images of each other, and radial symmetry, such as that in jellyfish, where body parts are arranged around a central axis.

Direct development occurs when an organism develops directly into a juvenile form without a larval stage as in, for example, insects that undergo metamorphosis, like butterflies. Indirect development occurs when an organism goes through a larval stage, which is often very different from the adult form, such as in, for example, sea stars, where the adult form is a sessile animal, but the larva is a planktonic organism.

Protostomes are characterized by coelom formation through schizocoely where the coelom forms by splitting of mesodermal tissue, whereas coelom formation in deuterostomes, such as sea stars, occurs by enterocoely, where the coelom arises from pouches extending off the archenteron.

<p>Acoelomates, such as flatworms (Phylum Platyhelminthes), lack a true coelom, while pseudocoelomate animals, such as roundworms (Phylum Nematoda), possess a pseudocoelom, a fluid-filled space, between the body wall and the internal organs.</p> Signup and view all the answers

<p>A sessile invertebrate, such as a barnacle, remains attached to a surface and cannot move freely, while a sedentary invertebrate, such as a sea urchin, may move but generally stays within a delimited area.</p> Signup and view all the answers

<p>The intertidal zone is a dynamic environment where marine invertebrates must adapt to periodic exposure to air and changes in salinity due to tidal fluctuations. Organisms like barnacles and crabs have developed adaptations to withstand these challenges.</p> Signup and view all the answers

<p>Direct development, such as in the case of insects, is when an animal develops directly from an egg into a juvenile form without a larval stage. Organisms that possess no germ layer, such as sponges (Phylum Porifera), are classified as Parazoa, meaning a group that lack tissues because they don't have germ layers. Indirect development occurs with animals that form a larval stage that may be quite different from the adult phase, such as the sea star.</p> Signup and view all the answers

<p>In a protostome, the mouth develops from the blastopore, a primary opening in the gastrula, while in a deuterostome, the mouth develops secondarily, and the blastopore becomes the anus.</p> Signup and view all the answers

<p>A species gene pool encompasses all the genetic material shared by members of a particular species, capable of interbreeding and producing offspring. It differs from other species' gene pools, reflecting their unique evolutionary history and genetic makeup. This difference in gene pools signifies the distinct evolutionary pathways and relationships between different species.</p> Signup and view all the answers

<p>The binomial nomenclature system assigns a scientific name to each species, consisting of two parts: the generic name, which starts with a capital letter and denotes the genus to which the species belongs, and the specific name, which refers to the specific species within that genus. For example, <em>Homo sapiens</em> is the scientific name for humans, where 'Homo' represents the genus and 'sapiens' indicates the specific species.</p> Signup and view all the answers

<p>Planktonic organisms are passively drifting or wandering in the water column, like phytoplankton, while benthic organisms inhabit the ocean floor, either on the surface or within the sediments. Examples include sea anemones (benthic) and jellyfish (planktonic).</p> Signup and view all the answers

<p>Suspension feeders filter small food particles from the surrounding water using specialized structures, such as baleen plates in whales or gills in clams. Deposit feeders, on the other hand, ingest sediments and extract organic matter from them. Examples include sandworms (deposit feeders) and barnacles (suspension feeders).</p> Signup and view all the answers

<p>Commensalism is a symbiotic relationship where one organism benefits, while the other is neither harmed nor benefited. An example is the relationship between barnacles and whales: the barnacles benefit by having a stable substrate to attach to, while the whales are not affected significantly.</p> Signup and view all the answers

Connection among organisms based on shared ancestry.

The total genetic diversity within a species.

The two-part scientific naming system for species.

Organisms living on the surface of their hosts.

A symbiotic relationship where both organisms benefit.

Organisms made of many specialized cells.

Organisms composed of a single cell without organelles.

Body plan where the left and right sides are mirror images.

Body parts arranged around a central axis.

Triploblastic organisms without a body cavity.

Organisms with a body cavity between the body wall.

Animals where the mouth forms first during development.

Animals where the anus forms first during development.