L10-Invertebrates (I) (Ko)

B) Lack of a cell wall

Explanation: Animal cells are characterized by the absence of a cell wall, which differentiates them from plant cells and many types of microorganisms.

B) Solitary, free-swimming marine invertebrates

Explanation: Ctenophores, also known as comb jellies, are solitary and free-swimming marine invertebrates, distinguishing them from other invertebrate groups.

C) Ectoderm

Explanation: The outer tissue layer of a cnidarian is derived from the ectoderm and forms the protective epidermis.

C) Digestion

Explanation: The inner tissue layer of a cnidarian, derived from the endoderm, secretes digestive enzymes into the gastrovascular cavity, aiding in digestion.

C) Swimming, responding to external stimuli, and engulfing prey

Explanation: The development of tissues in multicellular animals allows them to swim, respond to external stimuli, and engulf prey, among other functions.

B) Small, transparent, and sometimes bioluminescent

Explanation: Ctenophores are typically small, transparent, and can sometimes exhibit bioluminescence, making them visually distinctive in their marine environments.

B) Animals are motile with well-developed nervous and muscular systems

Explanation: Animals are typically motile and have well-developed nervous and muscular systems that facilitate movement.

B) Sea anemones

Explanation: Sea anemones, along with jellyfishes, corals, and their relatives, are part of the Phylum Cnidaria, which is known for its diverse group of aquatic organisms.

D) Domain Eukarya

Explanation: Humans belong to the Domain Eukarya, which includes all organisms with eukaryotic cells, such as plants, animals, fungi, and protists.

D) Kingdom Animalia

Explanation: Kingdom Animalia consists of multicellular organisms that primarily obtain their nutrients through ingestion, distinguishing them from other kingdoms.

B) Kingdom Fungi

Explanation: Kingdom Fungi includes organisms like mushrooms and molds, which are known for their role in decomposition and nutrient cycling.

D) Endoderm

Explanation: The inner tissue layer of a cnidarian is derived from the endoderm and is responsible for secreting digestive enzymes into the gastrovascular cavity.

C) Organisms with body shapes that are mirror images along a single centerline

Explanation: Bilateral symmetry refers to organisms whose body shapes are mirror images along a single centerline, dividing the body into left and right sides.

C) Asymmetrical

Explanation: Sponges are asymmetrical, meaning they lack any form of symmetry and do not have a predictable pattern to their body shape.

D) Domain Archaea

Explanation: Domain Archaea includes organisms that are known for living in extreme environments, such as hot springs, deep-sea vents, and other harsh conditions.

C) Heterotrophic

Explanation: Animals are heterotrophic, meaning they ingest and digest food internally, unlike plants that produce their own food through photosynthesis.

B) Mouth directed upward

Explanation: The polyp form of cnidarians is characterized by having its mouth directed upward, typically attached to a substrate.

B) Mouth directed downward

Explanation: The medusa form of cnidarians has its mouth directed downward, which is a distinguishing feature of this body form.

B) Animals typically develop from three germ layers: ectoderm, mesoderm, and endoderm

Explanation: Most animals develop from three primary germ layers: ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer), each giving rise to different tissues and organs.

D) Radial symmetry

Explanation: Radial symmetry is not a characteristic of bilateral symmetry. Bilateral symmetry includes left and right sides, dorsal and ventral sides, anterior and posterior ends, and cephalization.

D) They lack a defined body pattern

Explanation: Asymmetry in animals, such as sponges, indicates that these organisms lack a defined body pattern and do not exhibit any form of symmetry.

B) Left and right, dorsal (top) and ventral (bottom)

Explanation: An organism with bilateral symmetry has distinct left and right sides, as well as dorsal (top) and ventral (bottom) sides.

C) Their primary stage is medusa

Explanation: True Jellyfish (Sea Jellies) primarily exist in the medusa stage, while the polyp stage remains small.

A) Freshwater

Explanation: While Cnidarians mainly live in shallow coastal waters, some species can also be found in freshwater, brackish, and oceanic forms.

C) Presence of true tissues

Explanation: Both Ctenophores and Cnidarians have true tissues, distinguishing them from more primitive organisms that lack organized tissue structures.

C) Comb jellies

Explanation: Ctenophores are commonly referred to as comb jellies, a name derived from the comb-like ciliary plates they use for locomotion.

C) Sponge

Explanation: Sponges are an example of asymmetry in the Animal Kingdom, meaning they lack symmetry and do not exhibit any particular pattern to their body shape.

C) A series of developmental stages with specialized tissues

Explanation: Animals undergo a series of developmental stages, during which specialized tissues form to perform specific functions.

A) Polyp

Explanation: The polyp form is generally sessile, meaning it is attached to a substrate, unlike the free-swimming medusa form.

B) Vertebrates have a spinal cord, invertebrates do not

Explanation: Vertebrates are characterized by having a spinal cord (backbone) at some stage of their life, whereas invertebrates lack a spinal cord.

C) They regroup and form a new sponge

Explanation: If sponge cells are experimentally separated, they have the ability to regroup and form a new sponge, demonstrating their unique regenerative properties.

C) Has a nerve net

Explanation: Hydra, a freshwater cnidarian, has a nerve net consisting of interconnected nerve cells, which allows it to respond to stimuli.

C) Lack of complex body structures

Explanation: Simple invertebrates are defined by their lack of complex body structures and systems, making them fundamentally different from more advanced invertebrates.

B) Shallow coastal waters

Explanation: Most Cnidarians mainly inhabit shallow coastal waters, although some species can be found in freshwater, brackish, and oceanic environments.

C) Kingdom Plantae

Explanation: Kingdom Plantae includes organisms that perform photosynthesis, converting light energy into chemical energy stored in glucose.

B) Bilateral symmetry

Explanation: Most animals exhibit bilateral symmetry, where the body can be divided into two identical halves along a single plane.

C) Porifera

Explanation: Sponges belong to the phylum Porifera, which is characterized by their porous bodies and simple organization.

C) By collar cells within their food vacuoles

Explanation: Food particles in the water are trapped by collar cells and digested within their food vacuoles.

C) It forms the protective epidermis

Explanation: The outer tissue layer of cnidarians, derived from the ectoderm, forms the protective epidermis.

C) As sessile filter feeders

Explanation: Sponges are sessile filter feeders, meaning they remain fixed in one place and filter water to extract their food.

B) Allows for directed movement towards food and mates, and away from danger

Explanation: Bilateral symmetry enables animals to engage in directed movement, helping them move towards food and mates and away from dangers.

C) Sponges

Explanation: Sponges are considered simple invertebrates because they lack specialized tissues and organs, and they represent one of the most basic forms of animal life.

C) Cnidarians

Explanation: Diploblastic animals, such as cnidarians, have embryos with only two tissue layers: ectoderm and endoderm.

B) A body plan where the organism can be divided into many equal parts from a common center point

Explanation: Radial symmetry refers to a type of body plan where an organism can be divided into many equal parts from a common center point (central axis).

B) Cnidocyte

Explanation: Cnidarians possess specialized stinging cells known as cnidocytes, which play a crucial role in their defense and prey capture mechanisms.

B) Evolution of multicellular animals with tissues

Explanation: The next level of organizational complexity after sponges is marked by the evolution of multicellular animals with tissues that perform specific functions.

C) They are multicellular

Explanation: All animals are multicellular organisms, which means they are composed of multiple cells that work together to perform various functions.

B) Epidermal cells and collar cells

Explanation: The wall of a sponge contains two layers of cells: the outer epidermal cells and the inner collar cells.

B) To move water through pores

Explanation: The flagella on collar cells beat to move water through the pores of the sponge, aiding in the capture of food particles.

B) Medusa

Explanation: The medusa form is typically free-swimming, in contrast to the polyp form, which is usually sessile and attached to a substrate.

D) They have a cellular level of organization

Explanation: Sponges are the only animals that lack true tissues and have only a cellular level of organization, distinguishing them from more complex animals.

A) They are multicellular eukaryotes

Explanation: Animals are defined as multicellular eukaryotic organisms, which distinguishes them from unicellular organisms and prokaryotes.

A) Jellyfish

Explanation: Jellyfish are considered simple invertebrates because they lack complex structures and systems found in more advanced invertebrates.

C) Earthworm

Explanation: Earthworms are not simple invertebrates; they belong to a more complex group of invertebrates with segmented bodies and more developed organ systems.

C) Invertebrates and fishes

Explanation: True Jellyfish (Sea Jellies) feed on invertebrates and fishes, making them an important part of the marine food chain.

B) Repeating a body part 4 times around the axis

Explanation: Tetramerism is the repetition of a body part 4 times around the central axis in radially symmetrical animals.

D) Radial symmetry

Explanation: Cnidarians, which include jellyfish, corals, and sea anemones, exhibit radial symmetry. This means their body plan is arranged around a central axis, allowing them to interact with their environment from all directions.

B) Greek for 'thread'

Explanation: The term 'nematocyst' is derived from the Greek word 'nema,' meaning 'thread,' which refers to the thread-like structure contained within the nematocyst.

B) Two germ layers

Explanation: The embryos of both Ctenophores and Cnidarians have two germ layers, specifically the ectoderm and endoderm, which is a characteristic feature of these phyla.

B) Radial symmetry

Explanation: Adults of both Ctenophores and Cnidarians exhibit radial symmetry, meaning their body parts are arranged around a central axis, which is typical for these groups.

D) They lack symmetry

Explanation: Asymmetrical animals, such as sponges, lack symmetry and do not have any particular pattern to their body shape.

B) They transport nutrients from cell to cell

Explanation: Amoebocytes are responsible for transporting nutrients from cell to cell in sponges.

C) Polyp has mouth directed upward, medusa has mouth directed downward

Explanation: The primary difference between these two body forms is the orientation of the mouth: the polyp's mouth is directed upward, while the medusa's mouth is directed downward.

B) Invertebrates include both simple and complex organisms

Explanation: Invertebrates encompass a wide range of organisms, from simple to complex, and they can be found in various environments including marine, terrestrial, and freshwater habitats.

B) Presence of complex organs and systems

Explanation: Other invertebrates often possess complex organs and systems, which are generally absent in simple invertebrates.

C) Both sexually and asexually

Explanation: Hydra can reproduce both sexually and asexually, showcasing their versatile reproductive strategies.

A) Mouth

Explanation: In deuterostomes, the second embryonic opening becomes the mouth, with the anus developing first. The term 'deuterostome' comes from the Greek 'deuter' meaning 'second'.

E) Asexual reproduction

Explanation: Many invertebrates exhibit asexual reproduction, which allows them to reproduce without the need for a mate. This strategy can include processes such as budding, fragmentation, or binary fission.

B) The nematocyst is discharged

Explanation: When the trigger of a cnidocyte is touched, it causes the nematocyst to discharge, releasing the coiled thread to capture prey or deter predators.

C) Both sexually and asexually

Explanation: Many animals have the capability to reproduce both sexually and asexually, and some can combine both reproductive cycles.

B) Gastrovascular cavity

Explanation: The gastrovascular cavity in cnidarians is where digestive enzymes are secreted by the inner tissue layer, aiding in the digestion process.

C) They all descended from a common ancestor

Explanation: All animals are descended from a common ancestor, which is a fundamental concept in understanding the evolutionary relationships among different animal species.

B) Development of brain and specialized sensory organs at the anterior end

Explanation: Cephalization refers to the concentration of brain and specialized sensory organs at the anterior end of an organism, which is a typical feature of bilaterally symmetrical animals.

C) At some stage of their life

Explanation: Vertebrates possess a spinal cord (backbone) at some stage of their life, which may be during embryonic development or later stages.

B) They have a nerve net

Explanation: Simple invertebrates such as cnidarians have a nerve net, which is a decentralized form of a nervous system, in contrast to the more complex nervous systems found in higher animals.

C) Three

Explanation: Triploblastic animals have three tissue layers: ectoderm, mesoderm, and endoderm.

D) They have a distinct head and tail

Explanation: Radially symmetrical animals do not have a distinct head and tail; instead, they extend out in all directions from a central point.

C) Defense and prey capture

Explanation: The nematocyst in cnidarians functions primarily for defense and prey capture, utilizing its coiled thread to immobilize or deter threats.

C) They possess stinging cells called cnidocytes

Explanation: Cnidarians are characterized by the presence of cnidocytes, specialized cells that contain stinging structures used for capturing prey and defense.

D) They lack a particular pattern to body shape

Explanation: Sponges lack symmetry and do not have a specific pattern to their body shape, making them an example of asymmetry in the Animal Kingdom.

C) Needle-shaped structures forming an internal skeleton

Explanation: Spicules are needle-shaped structures that form the internal skeleton in some sponges.

C) They do not have a spinal cord

Explanation: Invertebrates are defined by their lack of a spinal cord (backbone), distinguishing them from vertebrates.

B) They are saclike and perforated by many pores

Explanation: Sponges have saclike bodies that are perforated by many pores, allowing water to flow through and facilitating their filter-feeding mechanism.

B) Arthropods

Explanation: Arthropods include invertebrates such as spiders, insects, and crustaceans, characterized by their exoskeleton and segmented bodies.

B) Mouth

Explanation: In protostomes, the first embryonic opening becomes the mouth, hence the name derived from Greek 'proto' meaning 'first' and 'stoma' meaning 'mouth'.

B) They possess comb-like cilia for movement

Explanation: Ctenophores (Phylum Ctenophora), also known as comb jellies, are distinguished by their rows of comb-like cilia that they use for locomotion. This unique feature sets them apart from other invertebrates.

B) They possess stinging cells called cnidocytes

Explanation: Cnidarians are known for their specialized stinging cells called cnidocytes, which they use for capturing prey and defense. These cells contain nematocysts that can deliver a sting to potential threats or prey.

C) Both asexual and sexual reproduction

Explanation: Sponges can reproduce both asexually through fragmentation or budding and sexually by releasing eggs and sperm into the central cavity.

C) They generally lack specialized tissues and organs

Explanation: Simple invertebrates typically lack specialized tissues and organs, which differentiates them from more complex invertebrates and vertebrates.

A) Germ layers

Explanation: Germ layers are the first tissue layers that appear during embryonic development, giving rise to the organs and organ systems of complex animals.

E) All of the above

Explanation: Sponges, ctenophores, cnidarians, and Phylum Placozoa are not triploblastic animals; they do not have three tissue layers.

C) They have a simple body plan with no tissues

Explanation: Sponges (Phylum Porifera) are characterized by their simple body plan that lacks true tissues and organs. They are primarily aquatic and have a porous body structure.

C) They develop from two or three primary tissue layers

Explanation: Most animals develop from two or three primary tissue layers during embryonic development. These layers, known as germ layers, include the ectoderm, mesoderm, and endoderm, which give rise to different tissues and organs in the adult organism.

B) Freshwater

Explanation: Hydra are freshwater cnidarians, distinguishing them from many other cnidarians that are typically marine.

C) 5 times

Explanation: Pentamerism refers to the repetition of a body part 5 times around the central axis in radially symmetrical animals.

C) Planes dividing the body into many equal parts

Explanation: Planes of symmetry are the planes that divide the body into many equal parts around a central axis.

B) Nematocyst

Explanation: Each cnidocyte contains a nematocyst, which is a specialized organelle that houses a long, spirally coiled, hollowed thread used for capturing prey and defense.