1.
Which of the following is not characteristic of the phylum porifera ?
Correct Answer
A. Porous
Explanation
The characteristic of being porous refers to the ability of the phylum Porifera, which includes sponges, to have numerous small openings or pores in their bodies. This allows water to flow through them, facilitating filter feeding. Radial symmetry, sessile lifestyle, and multicellularity are all characteristics of Porifera, so they are not the correct answer. Therefore, the correct answer is porous.
2.
Which environment would be most suitable for most sponges ?
Correct Answer
C. Mud flat
Explanation
Sponges are filter feeders that rely on a constant supply of food particles in the water. Mud flats are rich in organic matter and nutrients, making them an ideal environment for sponges. The mud provides a stable substrate for attachment, and the flat nature of the area ensures a constant supply of water and food particles. Additionally, the quiet nature of mud flats reduces disturbances that could disrupt sponge feeding and growth. Overall, mud flats provide the most suitable environment for sponges to thrive.
3.
The cell in the sponges responsible for producing water circulation is the
Correct Answer
B. Spicule
Explanation
The spicule is a structure found in sponges that provides support and rigidity to the sponge's body. It is made of calcium carbonate or silica. However, the spicule is not responsible for producing water circulation in sponges. Water circulation in sponges is primarily facilitated by specialized cells called choanocytes. Choanocytes have a flagellum that creates water currents, allowing the sponge to filter out food particles and exchange gases. Therefore, the correct answer is not spicule but choanocyte.
4.
Members of the phylum porifera that are used commercially as sponges have a skeleton of
Correct Answer
B. Spongocoel
Explanation
The correct answer is spongocoel. The spongocoel is a central cavity found in sponges where water enters and circulates. Sponges that are used commercially as sponges typically have a skeleton made up of spicules (tiny, needle-like structures) and spongin (a proteinaceous substance). However, the spongocoel is the correct answer as it refers to the specific structure within the sponge.
5.
All sponges share one of these characteristics
Correct Answer
C. Multicellular
Explanation
The given answer, multicellular, is correct because all sponges share this characteristic. Being multicellular means that sponges are made up of multiple cells working together to form a complex organism. This is in contrast to single-celled organisms. Multicellularity allows sponges to have specialized cell types and perform various functions, such as feeding, reproduction, and defense.
6.
A larva is best defined as;
Correct Answer
C. Immature stage of an animal that looks different from the adult
Explanation
A larva is an immature stage of an animal that looks different from the adult. This stage is characterized by distinct physical features and behaviors that are different from the adult form. Larvae undergo metamorphosis to transform into the adult form. This definition distinguishes a larva from other options such as an early colony of cells, a reproductive stage, or a free-living sperm cell in water.
7.
Sponges are sessile their entire life
Correct Answer
B. False
Explanation
Sponges are not sessile their entire life. While they do spend most of their life attached to a substrate, some species of sponges are able to move in response to environmental conditions. Additionally, sponges have larval stages that are free-swimming before they settle down and become sessile. Therefore, the statement is false.
8.
Sponges are eaten by many other marine animals
Correct Answer
B. False
Explanation
Sponges are not eaten by many other marine animals. While some animals may feed on sponges, they are generally not a preferred food source for most marine animals. Sponges have a tough and fibrous texture, making them difficult to consume. They also contain toxic compounds that deter many predators. Therefore, it is incorrect to say that sponges are eaten by many other marine animals.
9.
Like most marine organisms, sponges have gills for gas exchange
Correct Answer
B. False
Explanation
Sponges do not have gills for gas exchange. Unlike most marine organisms, sponges rely on diffusion through their porous bodies to exchange gases with the surrounding water. They do not possess specialized respiratory structures like gills. Therefore, the statement is false.
10.
The name porifera means __________
Correct Answer
Pores
Explanation
The name "porifera" means pores, as it is derived from the Latin word "porus" which means pore. Porifera is the scientific name for the phylum of animals commonly known as sponges. Sponges have numerous pores on their bodies through which water flows, allowing them to filter out microscopic food particles. The name "porifera" accurately describes this characteristic feature of sponges.
11.
The two main sources of food for sponges are organic particles and _______________
Correct Answer
Plankton
Explanation
Sponges primarily obtain their food from two sources: organic particles and plankton. Plankton refers to a diverse group of small organisms that float or drift in water, including microscopic plants (phytoplankton) and animals (zooplankton). These organisms serve as a vital food source for sponges, as they can filter and consume them from the surrounding water. Therefore, plankton is a crucial component of the diet of sponges, along with other organic particles present in their environment.
12.
Two main types of asexual reproduction sponges are regeneration and ______________
Correct Answer
sex
Explanation
The question is asking for the term that completes the sentence about the two main types of asexual reproduction in sponges. The term "sex" completes the sentence because it contrasts with asexual reproduction. Asexual reproduction does not involve the fusion of gametes, while sexual reproduction does. Therefore, "sex" is the correct answer to complete the sentence.