Diversity Of Living Things: Chapter 4

Invertebrates are a diverse group of animals that do not possess a backbone or vertebral column. This characteristic distinguishes them from vertebrates, which have a well-developed backbone. Invertebrates can range in size from microscopic organisms to large animals like squids and octopuses. They obtain energy through various methods such as filter feeding, predation, or parasitism. Therefore, the statement "they lack a backbone" is true for all invertebrates.

A sponge obtains energy by filtering food from the water around it. Sponges are filter feeders, meaning they extract nutrients by pumping water through their bodies and filtering out organic particles such as bacteria, plankton, and detritus. They have specialized cells called choanocytes that have flagella to create water currents and trap food particles. The trapped food is then digested by the sponge's cells, providing it with energy. This method of obtaining food is common among sponges and allows them to survive in their aquatic environments.

An invertebrate is an animal that does not have a backbone or spinal column. The wolf is a vertebrate because it has a backbone, making it the incorrect answer. Yeast is a type of fungus and not an animal, so it is also not an invertebrate. On the other hand, a crab is an invertebrate because it belongs to the arthropod group, which includes animals without a backbone. Therefore, the correct answer is crab.

Worms do not have noses or lungs to absorb oxygen. Instead, they have a moist and permeable skin that allows them to absorb oxygen directly from their environment. This is why worms need to stay moist, as dry conditions can prevent oxygen absorption and lead to suffocation. Therefore, the correct answer is "through the skin."

Cnidarians' tentacles are adapted to catch prey and protect the animal from predators. These tentacles are equipped with specialized cells called cnidocytes that contain stinging structures called nematocysts. When prey comes into contact with the tentacles, the nematocysts are triggered and inject venom into the prey, immobilizing it. This allows the cnidarian to capture and consume its prey. Additionally, the tentacles serve as a defense mechanism against predators, as they can deliver a painful sting.

Arthropods have a hard outer covering called an exoskeleton that protects their soft body from drying out. The exoskeleton acts as a protective armor, providing support and preventing water loss. It is made of a tough material called chitin and provides structural integrity to the arthropod's body. This adaptation allows arthropods to thrive in a variety of environments, including both terrestrial and aquatic habitats.

Most worms have complex body systems because they are multicellular organisms with specialized organs and tissues. These body systems allow them to perform various functions such as digestion, respiration, circulation, and reproduction. Worms have a well-developed nervous system, muscular system, and digestive system, among others. Their complexity enables them to adapt to different environments and carry out essential biological processes for their survival and reproduction.

Cnidarians are invertebrates that live in water only because they are aquatic animals. They have adaptations that allow them to survive and thrive in aquatic environments, such as the presence of tentacles and stinging cells for capturing prey, and a simple body structure that enables them to move and float in water. Cnidarians, such as jellyfish and corals, have a symbiotic relationship with algae, which requires them to live in water for photosynthesis to occur. Therefore, the correct answer is "in water only."

Bilateral symmetry refers to the arrangement of body parts in a way that can be divided into two similar halves along a central plane. In the case of an earthworm, its body can be divided into two equal halves along its longitudinal axis. This means that the left and right sides of the earthworm's body are mirror images of each other. This type of symmetry is advantageous for earthworms as it allows for efficient movement and coordination.

The layer of skin that protects a snail's organs and produces its shell is called the mantle. The mantle is a thin layer of tissue that covers the snail's body and secretes calcium carbonate, which forms the snail's shell. It also helps in respiration and excretion. The foot is a muscular organ used for movement, the gill is used for breathing in aquatic organisms, and the spine is a bony structure found in vertebrates.

Crustaceans are a group of arthropods that include animals like crabs, lobsters, and shrimp. They are well adapted to living in aquatic environments, such as oceans, rivers, and lakes. Their bodies are designed with features like gills for breathing underwater, and they rely on water to survive. Therefore, it is correct to say that most crustaceans live in water.

Most arthropods are insects because insects are the largest and most diverse group within the phylum Arthropoda. They have a distinct body structure consisting of three main parts: head, thorax, and abdomen. Insects also have six legs, two antennae, and usually one or two pairs of wings. They play crucial roles in various ecosystems as pollinators, decomposers, and as a food source for other organisms. Additionally, insects have adapted to various habitats and exhibit a wide range of behaviors and feeding habits.

Echinoderms use their water vascular system to move. The water vascular system consists of a network of fluid-filled canals and tube feet, which are used for locomotion. By contracting and relaxing their tube feet, echinoderms are able to move and navigate their environment. This system allows them to crawl, climb, and even swim in some species. Therefore, the correct answer is move.

Radial symmetry is an adaptation of most sessile organisms. This means that these organisms are symmetrical around a central axis, with body parts arranged in a circular pattern. This adaptation allows them to equally distribute sensory organs and appendages around their body, enabling them to respond to stimuli from any direction. It also allows for efficient capture of food and protection from predators. Bilateral symmetry, on the other hand, is a type of symmetry found in organisms that are capable of moving actively. Rotational symmetry and hexagonal symmetry are not adaptations commonly found in sessile organisms.

Bivalves are aquatic organisms that live in water and rely on gills to extract oxygen from the surrounding water. Gills are specialized organs that are responsible for the exchange of gases, allowing the bivalve to take in oxygen and release carbon dioxide. The mantle, lungs, and feet are not involved in the respiratory process of bivalves.

Echinoderms are a group of marine animals that include starfish, sea urchins, and sea cucumbers. One characteristic that is true of all echinoderms is that they have internal skeletons. These skeletons are made up of calcium carbonate plates or ossicles, which provide support and protection for the animal's body. The internal skeleton also serves as an attachment point for the echinoderm's muscles, allowing them to move and manipulate their environment. This feature distinguishes echinoderms from other invertebrates, which often have external skeletons or no skeletons at all.

Spiders, crabs, and bees belong to the largest group of invertebrates because they are all arthropods. Arthropods are the largest phylum of invertebrates and include a wide range of species with diverse characteristics. This group is characterized by having jointed limbs, a segmented body, and an exoskeleton. Spiders, crabs, and bees are all examples of arthropods and therefore belong to the largest group of invertebrates.

Arachnids have 8 legs and 2 body segments. This distinguishes them from millipedes, centipedes, and insects, which have different leg and body segment counts.

Arthropods reproduce sexually. This means that they require both a male and a female to reproduce, with the fusion of gametes from each parent. This process involves meiosis, which is a type of cell division that produces gametes with half the number of chromosomes as the parent cells. Through sexual reproduction, arthropods are able to produce offspring with genetic variation, which can be beneficial for their survival and adaptation to changing environments.

Sponges are capable of reproducing both sexually and asexually. They reproduce sexually by producing eggs and sperm, which are released into the water where fertilization occurs. Additionally, sponges can reproduce asexually through a process called budding. In budding, a new sponge grows as an outgrowth from the parent sponge and eventually detaches to become an independent organism. Therefore, sponges have the ability to reproduce both sexually and asexually, ensuring the continuation of their species through different mechanisms.

Molting is the process in which an arthropod sheds its exoskeleton. This allows the arthropod to grow and develop a new, larger exoskeleton. Shedding its skin is a common phrase used to describe this process, as the exoskeleton is similar to a protective skin for the arthropod. Hibernation is a different process where an animal goes into a state of dormancy during the winter to conserve energy.