৪৯তম বিসিএস ⎯ প্রাণিবিদ্যা [৫৯১]

Sexual dimorphism, which refers to the distinct difference in size, shape, or appearance between the sexes of the same species, is commonly observed in Nematoda (roundworms). Therefore, the correct answer is:
খ) Nematoda

Source: Britannica

Species Diversity: Species diversity is the number of different species in a particular area and their relative abundance. Panthera tigris  and Panthera leo are belongs to the same genus but they show considerable differences .   

Ecological Diversity: Ecological diversity, also known as ecosystem diversity, refers to the variety of ecosystems within a specific geographical area, including the different types of habitats, communities, and ecological processes.

সঠিক উত্তর: গ) Scypha gelatinosum ও ঘ) Fasciola hepatica 
​অপশনে দ্বৈত উত্তর থাকায় প্রশ্নটি বাতিল করা হলো। 
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​Hydra vulgaris - it belongs to phylum Cnidaria is a tissue  grade animal. 
Scypha gelatinosum-  It is  called sponge and is a cellular grade animal. 
Ascaris lumbricoides - it belongs to phylum Nematoda whose coelom is pseudocoelom.
Fasciola hepatica - It is a triploblastic animal and has no coelom means Acoelomate. 

Platyhelminthes - Triploblastic 
Apicomplexa - Unicellular animal 
Nematoda - Pseudocoelomate 

Source: Britannica & ScienceDirect.

Euspongia officinalis -  this animal  is form phylum porifera 
Aurelia aurita  - This is called jelly fish and belongs to Phylum Cnidaria 
Fascioa hepatica - The larval stages of Fasciola hepatica, the liver fluke, are crucial to its life cycle and involve several distinct forms. These include miracidia, sporocysts, rediae, and cercariae, with the latter eventually encysting as metacercariae. Humans can become infected by ingesting metacercariae, which are found on aquatic plants like watercress

Rhabditiform larvae is the characteristic of the nematodes. Splitting of the eggs of intestinal roundworm parasites releases rhabditiform larvae in the intestine where they reach the liver through the portal circulation, later they enter into the heart via pulmonary circulation and finally enter the lungs.

Planula larvae  - A planula larva is a free-swimming, ciliated larva characteristic of many Cnidarians (like jellyfish, corals, and sea anemones) and some Ctenophores. It is typically oval or oblong, flattened, and covered in cilia, which it uses for locomotion. Planulae develop from fertilized eggs and eventually settle to the seafloor, where they transform into the polyp stage of their life cycle. 

Endosymbiont-Porifera, or sponges, host a diverse range of endosymbionts, including bacteria, archaea, and even algae, which play crucial roles in their survival and ecology. These endosymbionts contribute to nutrient acquisition, defense against pathogens, and overall sponge health.  
Porifera, commonly known as sponges, are simple, multicellular aquatic animals characterized by their porous body structure, cellular level of organization, and lack of true tissues and organs. They are mostly marine, but some live in freshwater. Key features include ostia (small pores for water intake), osculum (a larger opening for water exit), and a central cavity called the spongocoel. 
Osculum present 
common name sponge 

Flame cells are specialized cells found in certain simple invertebrates, like flatworms, rotifers, and nemerteans, that function as part of their excretory system. 

Ascaris lumbricoides - Sexual dimorphism present 
Euspongia officinalis - cellular grade animal and does not have gamete 
Fasciola hepatica -larvae present 
Porpita porpita (blue button) -Porpita porpita is a colonial polymorphic hydrozoan distributed in temperate and tropical zones. This species, like most hydrozoans, possesses a metagenetic life cycle with alternating life forms: medusa stage, polypoid colony, and planula larva.

Ascaris lumbricoides, a type of roundworm, causes ascariasis, a parasitic infection of the intestines. 
Pila globossa - It is called apple snail . 
Hydra vulgaris - It is a cnidarian animal. 

Source: WHO

Porifera, commonly known as sponges, are classified into three main classes:Calcarea, Hexactinellida, and Demospongiae.
The phylum Platyhelminthes, commonly known as flatworms, is traditionally divided into four classes: Turbellaria, Trematoda, Cestoda, and Monogenea
The phylum Nematoda, commonly known as roundworms, is primarily divided into two classes: Adenophorea and Secernentea
The phylum Cnidaria is divided into four main classes: Hydrozoa, Scyphozoa, Cubozoa, and Anthozoa. 

Nematoda -Pseudocoelomate 
Porifera - Spongocoel 
Cnidaria - Gastrovascular cavity 
Platyhelminthes - Acoelomate 

Sarcomastigophora, a diverse phylum of protozoa, primarily reproduce asexually through binary fission
Apicomplexa reproduce both sexually and asexually, often through complex, alternating cycles
Ciliates, belonging to the phylum Ciliophora, reproduce both asexually and sexually. 
Asexual reproduction primarily occurs through binary fission, while sexual reproduction involves a process called conjugation. 

Eimeria is a genus of protozoan parasites belonging to the phylum Apicomplexa, class Conoidasida, and order Eimeriida 

Ecological diversity- Ecological diversity, also known as ecosystem diversity, refers to the variety of ecosystems within a specific geographical area, including the different types of habitats, communities, and ecological processes
Genetic  diversity Genetic diversity refers to the variation in genes and inherited traits within a species or population
Species diversity refers to the variety of different species found in a specific location or ecosystem

A biome is a large geographic area characterized by specific climate conditions, plant life, and animal life.

Sarcomastiphora - Phylum 
Mastigophora -  Euglena 
Opalinata - Opalina 
Sarcodina - Amoeba 

mesoderm - The middle germinal layer of an animal 
Mesoglea - it presents in diploblastic animals in the middle of the ectodermis and gastrodermis 
Coelom - The coelom is the mesodermally lined cavity between the gut and the outer body wall.
It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer)

Rainforest of the sea" is a common nickname for coral reefs, due to their incredible biodiversity and the vital role they play in supporting marine life. These animals belong to Phylum Cnidaria 

Porifera, commonly known as sponges, are simple, multicellular aquatic animals characterized by their porous body structure, cellular level of organization, and lack of true tissues and organs. They are mostly marine, but some live in freshwater. Key features include ostia (small pores for water intake), osculum (a larger opening for water exit), and a central cavity called the spongocoel. 

Nematodes, also known as roundworms, are characterized by their cylindrical, unsegmented bodies, a flexible cuticle, a complete digestive system, and a pseudocoelom

Ascaris lumbricoides (roundworm),
Enterobius vermicularis (pinworm),
Wuchereria bancrofti (causes elephantiasis)
Fasciola hepatica -liver fluke 

Cnidaria - Diploblastic 
Porifera - Cellular grade 
Platyhelminthes - Flat and worm like 
Nematoda - Tube within tube 

» Hydra - Hydra is a cnidarian (a group of animals that includes jellyfish, corals, and sea anemones) and contains specialized cells called cnidocytes, which contain nematocysts (stinging capsules). Nematocysts are used for defense and capturing prey. 

» Pramecium - has cilia 
» Euspongia -  Sponge 
» Eimeria - Apicomplexa 

Source: Sciencedirect.com

Apicomplexa - Perkinsea, Sporozoa 
Sarcomastigophora - It is divided into three subphyla: the Mastigophora, the Sarcodina and the Opalinata
ciliophora - The phylum Ciliophora, commonly called ciliates, is a group of protists characterized by the presence of hair-like cilia on their cell surface and two types of nuclei: a diploid micronucleus and a polyploid macronucleus. Ciliates are classified into eight classes, including Prostomatea, Litostomatea, Karyorelictida, Spirotrichea, Phyllopharyngea, Nassophorea, Oligohymenophorea, and Colpodea
Nematoda - 

Class 1. Aphasmidia (Adenophorea)Class 2. Phasmidia (secernentea)

Obelia, a type of hydrozoan, exhibits a life cycle with both polyp and medusa stages. The polyp is a sessile, stalk-like form, often found in branching colonies attached to surfaces,

Plasmodium is responsible for malarial diseases .
 Eimeria disease, also known as coccidiosis, is a parasitic disease caused by protozoan parasites of the genus Eimeria

Paramecium, a single-celled eukaryote, possesses a unique dual nuclear structure consisting of a macronucleus and one or more micronuclei.

Source:
Aurelia 
biologywise

Protonephridia are Protonephridia are a type of excretory system found in some invertebrates, particularly in flatworms (Platyhelminthes) and other primitive animals.