Question

4) Diploblast marine animals with radial symmetry, mouth surrounded by tentacles covered with stinging cells (cnidocytes) with microscopic harpoons that paralyze prey belong to the phylum ____________

5) This very old animal phylum groups filter-feeding organisms whose bodies are covered with pores. They exhibit cell level of organization, and asymmetrical bodies:

6) The first group of triploblast animals with cephalization and a bilateral body symmetry belongs to the phylum __________________ .

7) Animals in the phylum ____________________ were the first to have a complete gut tube with two openings, mouth and anus. There are free-living and very abundant forms, and also parasitic forms that cause diseases to man and other vertebrates.

8) All worms with segmented body belong to the phylum ____________________.

9) Animals with soft slime body, with or without shell, are classified within this vey diverse phylum:

10) Indicate the name of the phylum and class of insects, crustaceans, spiders, scorpions, centipedes, and millipedes. How many known species are classified in this phylum?

11) What characteristic of sea urchins is shared with chordates making these marine animals the closest relatives to vertebrates?

12) What characteristic of the body of adult sea urchins is shared with cnidarians? 13) Describe the defining characteristics of chordates.
14) Describe the defining characteristics of the sub-phylum Vertebrata.
15) List the classes of vertebrates and their defining characteristics.

16) How many living species of vertebrates have been described?

Answer 1

Q4)  Diploblast marine animals with radial symmetry, mouth surrounded by tentacles covered with stinging cells (cnidocytes) with microscopic harpoons that paralyze prey belong to the phylum ____________.

Answer- Phylum - cnidaria .

Explanation:- Phylum cnidaria- All cnidarians are radially symmetrical, they have distinct tissue layers, they lack internal organs and central nervous systems. Most cnidarians have tentacles, and many have nematocysts (specialized stinging cells), which help in feeding.

Sea anemones are a group of marine, animals of order Actiniaria. They are classified under the phylum Cnidaria, class Anthozoa, subclass Hexacorallia. Sea anemone is a single polyp attached to a hard surface by its base, but some species live in soft sediment and a few float near the surface of the water. The polyp has a columnar trunk with an oral disc having a ring of tentacles and a central mouth. The tentacles can be retracted inside the body cavity or expanded to catch the prey. They have cnidocytes or stinging cells.

When a prey passes towards the sea anemone by the current, they get touched with the sea anemone’s hairy structures. This brushing sensation creates a reflex as a result tiny explosive cells found on tthe hairy structures called ’nematocysts’ or ‘cnidae’, get alerted . A hair-like trigger on the outside of the cell called a ’cnidocil’ is activated. These nematocysts contain a microscopic hollow tube having a toxin ( like a harpoon), coiled inside a bulbous cell. These come out of the cell and enters the prey, They come out in hundreds and thousands in a single trigger. After harpooning, the sea anemone gets attached to the newly paralysed or dead prey and starts eating it.

Q5)5) This very old animal phylum groups filter-feeding organisms whose bodies are covered with pores. They exhibit cell level of organization, and asymmetrical bodies:-

Answer- These are sponges belongs to phylum Porifera.

Explanation-Sponges belonging to the phylum porifera have an asymmetric body plan, have tiny pores (ostia) and channels all over the body which allows water to circulate through them, water along with the nutrients goes inside the body and comes out , They have a unique feeding system called filter feeding system.Sponges do not have a true circulatory system, instead of it they have a water current which is used for circulation.

Q6) The first group of triploblast animals with cephalization and a bilateral body symmetry belongs to the phylum

Answer- Acoelomorpha

Explanation-  Phylum Acoelomorpha are the most primitive bilateral triploblastic animals with cephalization and bilateral body symmetry. They differ from other triploblasts by not having a body cavity or coelom. They live in mud and sand in marine environments and move by the beating of cilia.

Q7) Animals in the phylum ____________________ were the first to have a complete gut tube with two openings, mouth and anus. There are free-living and very abundant

Answer- Nematode.

Explanation-

These animals are triploblastic, bilaterally symmetrical, unsegmented pseudocoelomates.

Nematodes lack a well-defined head, but they are the first animals to have a mouth and a anal opening with a complete gut tube. The roundworm uses the 16 organs in its mouth to bring food into its digestive system. From the mouth, the food goes into the pharynx , there it is crushed by muscles. The food then goes into the gut for digestion. The nutrients move to the cells and the waste moves out of the body, The waste gradually leaves the worm's body by its anal opening found at the opposite end of the cylindrical body.

8) All worms with segmented body belong to the phylum ____________________.

Answer- Annelida.

Explanation- The body of an Annelida is divided into repeating sections called segments, with many internal organs found repeated in each segment. They show organ level of body organization.

9) Animals with soft slime body, with or without shell, are classified within this very diverse phylum:

Answer- Mollusca.

Explanation-

Mollusca are one of the most diverse groups of animals on the planet, hhaving around 50,000 living species. It includes organisms like snails, octopuses, squid, clams, scallops, oysters, and chitons. These are soft-bodied, non-metameric, triploblastic coelomates and are bilaterally symmetrical invertebrates having a thin fleshy envelope called the mantle, in some organisms they have a calcareous shell.

10) Indicate the name of the phylum and class of insects, crustaceans, spiders, scorpions, centipedes, and millipedes. How many known species are classified in this phylum?

Answer- belongs to phylum - Arthropoda, Insects belong to class- Insecta, crustaceans like lobsters, crabs etc. belong to class - Malacostraca, spiders and scorpions belong to class- Arachnida, Centipedes belong to class- Chilopoda, Crustaceans belong to class- Diplopoda.

Around 1,170,000 and 5 to 10 million species are found in this phylum, and they constitute over 80 per cent of all known living animal species.