In other cnidarians the male releases sperm into the water, but fertilization happens inside the body when sperm from a male colony enters the female and fertilizes eggs internally.
- 1 Does cnidarians have internal or external fertilization?
- 2 How do cnidarians reproduce sexually?
- 3 What type of fertilization do cnidarians perform?
- 4 What is the asexual way of reproduction exhibited by cnidarians called?
- 5 Are Cnidaria unicellular or multicellular?
- 6 Why do cnidarians lack an internal skeletal system?
- 7 Is fertilization in molluscs external or internal?
- 8 What is external fertilization?
- 9 Do cnidarians have a digestive system?
- 10 Do arthropods reproduce sexually or asexually?
- 11 Are sexes separate in cnidaria?
- 12 Are Cnidaria hermaphrodites?
- 13 How do cnidarians feed?
- 14 Are cnidarians motile?
- 15 Which of the following is a characteristic associated only with cnidarians?
- 16 Do all molluscs have external fertilization?
- 17 How do Mollusca reproduce?
- 18 Are Cnidaria autotrophic or heterotrophic?
- 19 Can Mollusca reproduce asexually?
- 20 Are cnidarians unicellular?
- 21 Do cnidarians have true tissue?
- 22 Why are cnidarians considered tissue level and not organ level organization?
- 23 Do cnidarians have muscle tissue?
- 24 Is a cnidarian a Coelomate or Acoelomate?
- 25 Why amphibians and fishes have external fertilization?
- 26 Is fish external fertilization?
- 27 Are cnidarians carnivores?
- 28 Where do cnidarians live?
- 29 Do arthropods have internal or external fertilization?
- 30 What is external and internal fertilization?
- 31 What organs are found in Cnidaria?
- 32 Do arthropods have external fertilization?
- 33 Do arthropods have internal fertilization?
- 34 Where does digestion occur in cnidarians?
- 35 Do cnidarians move?
- 36 What did cnidarians evolved from?
- 37 Is a leech fertilization external or internal?
- 38 Is the development of a Cnidaria direct or indirect?
- 39 What is the larva of a cnidarian called?
- 40 How do medusa reproduce?
- 41 How do cnidarians respond to their environment?
- 42 Are cnidarians Diploblastic?
- 43 How do cnidarians excrete waste?
- 44 How do cnidarians maintain homeostasis?
- 45 Which is one characteristic of all cnidarians?
- 46 How many tissue layers do cnidarians have?
- 47 Which of the following are not cnidarians?
- 48 Is fertilization in molluscs external or internal?
- 49 Do mollusks reproduce internally?
- 50 What type of reproduction do amphibians have?
- 51 What type of reproduction does phylum Mollusca have?
- 52 Do cephalopods have internal fertilization?
- 53 Are gastropods asexual reproduction?
- 54 How do arthropods reproduce?
Does cnidarians have internal or external fertilization?
However, basal animals, such as medusozoan cnidarians (i.e., jellyfish) in which plesiomorphic external fertilization would be expected in adult medusae [2], offer several interesting examples of disparate jellyfish species exhibit- ing internal fertilization.
How do cnidarians reproduce sexually?
Cnidarian Reproduction
Polyps usually reproduce asexually. One type of asexual reproduction in polyps leads to the formation of new medusae. Medusae usually reproduce sexually. Sexual reproduction forms a zygote.
What type of fertilization do cnidarians perform?
Reproduction of Cnidarians
In general, polyps primarily reproduce asexually by budding, however, some produce gametes (eggs and sperm) and reproduce sexually. Medusae usually reproduce sexually using eggs and sperm.
What is the asexual way of reproduction exhibited by cnidarians called?
Cnidarians switch from the polyp to the medusa stage by a form of asexual reproduction in which the polyp develops a stack of medusoid structures that can then bud off to become independent medusae. This process is called strobilation and is depicted in Figure below.
Are Cnidaria unicellular or multicellular?
Cnidaria, phylum of multicellular, radially symmetrical invertebrates (eg, hydroids, jellyfish, sea anemones, corals) dating to late Precambrian era (630-570 million years ago).
Why do cnidarians lack an internal skeletal system?
A coelom is a fully-encased, fluid-filled body cavity (gut) lined with mesodermic tissue. Most complex, multicellular animals have a coelom. Cnidarians are not considered to have a coelom because they are diploblastic, so they don’t have any mesodermic tissue.
Is fertilization in molluscs external or internal?
Molluscs have extreme variation in reproductive characteristics. A generic mollusc is dioecious with paired gonads. Eggs or sperm are released into the coelomic cavity and carried outside by ducts. Fertilization is external and the zygote develops into a gastrula and then a free-swimming trochophore larva.
What is external fertilization?
Key Points. External fertilization is characterized by the release of both sperm and eggs into an external environment; sperm will fertilize the egg outside of the organism, as seen in spawning.
Do cnidarians have a digestive system?
Cnidarians perform extracellular digestion, with digestion completed by intracellular digestive processes. Food is taken into the gastrovascular cavity, enzymes are secreted into the cavity, and the cells lining the cavity absorb the nutrient products of the extracellular digestive process.
Do arthropods reproduce sexually or asexually?
Arthropods have a life cycle with sexual reproduction. Most species go through larval stages after hatching. The larvae are very different from the adults. They change into the adult form in a process called metamorphosis.
Are sexes separate in cnidaria?
Cnidarians have separate sexes and many have a lifecycle that involves two distinct morphological forms—medusoid and polypoid—at various stages in their life cycles. In species with both forms, the medusa is the sexual, gamete-producing stage and the polyp is the asexual stage.
Are Cnidaria hermaphrodites?
Cnidaria is a clade of gelatinous, primarily marine species with both gonochoristic and hermaphroditic forms.
How do cnidarians feed?
Cnidarians are carnivores, and some can also consume plant matter. They catch their food using their nematocysts or through filter feeding. Cnidarians digest their food using a primitive digestive system that contains no organs–they have a mouth (which also serves as the anus) and a gastrovascular cavity.
Are cnidarians motile?
Medusa forms are motile, with the mouth and tentacles hanging down from an umbrella-shaped bell. Cnidarian morphology: Cnidarians have two distinct body plans, the medusa (a) and the polyp (b). All cnidarians have two membrane layers, with a jelly-like mesoglea between them.
Which of the following is a characteristic associated only with cnidarians?
Which of the following is a characteristic associated only with cnidarians? cnidocytes specialized for defense and capturing prey.
Do all molluscs have external fertilization?
The simplest molluscan reproductive system relies on external fertilization, but with more complex variations. All produce eggs, from which may emerge trochophore larvae, more complex veliger larvae, or miniature adults.
How do Mollusca reproduce?
Mollusks reproduce sexually. Slugs and snails are hermaphrodites (possessing both male and female organs), but they must still mate to fertilize their eggs. Most aquatic mollusks lay eggs that hatch into small, free-swimming larvae called veliger.
Are Cnidaria autotrophic or heterotrophic?
The common characteristic to all of these animals is that they have stinging cells located, known as cnidocytes, on their tentacles. Because they belong to the animal kingdom, you can also assume that all cnidarians are multicellular and heterotrophic – meaning they must consume their food in some way.
Can Mollusca reproduce asexually?
Mollusks reproduce sexually, and most species have separate sexes. Sexual reproduction is achieved by the formation and fusion of gametes: sperm and eggs.
Are cnidarians unicellular?
Yes. Cnidaria is multicellular. Cnidaria are multicellular, radially symmetrical invertebrates, diploblastic with nematocysts.
Do cnidarians have true tissue?
Cnidarians are said to be the simplest organisms at the tissue grade of organization; their cells are organized into true tissues. Cnidarians are essentially bags made of two cell layers. The outer ectoderm, or epidermis, contains the cnidocysts, the stinging cells that are characteristic of the phylum.
Why are cnidarians considered tissue level and not organ level organization?
Cnidarians are radially or biradially symmetric, a general type of symmetry believed primitive for eumetazoans. They have achieved the tissue level of organization, in which some similar cells are associated into groups or aggregations called tissues, but true organs do not occur.
Do cnidarians have muscle tissue?
Muscles in cnidarians are extensions of the bases of ectodermal and endodermal cells. Individual muscle cells are relatively long and may occur in dense tracts in jellyfish or sea anemones. Most cnidarian muscles, however, are thin sheets at the base of ectodermal and endodermal layers.
Is a cnidarian a Coelomate or Acoelomate?
Yes, animals of the phylum Porifera and Cnidaria are acoelomates. They do not possess a body cavity, which is lined by mesoderm. Also Check: Coelom.
Why amphibians and fishes have external fertilization?
External fertilization typically occurs in water or a moist area to facilitate the movement of sperm to the egg. The release of eggs and sperm into the water is known as spawning. In motile species, spawning females often travel to a suitable location to release their eggs.
Is fish external fertilization?
The vast majority of the greater than 33 000 species of bony fishes reproduce using external fertilization, a broad term that describes the release of sperm and eggs into the external environment and ranges from broadcast spawning to the direct placement of sperm onto eggs.
Are cnidarians carnivores?
All cnidarians are carnivores. Most use their cnidae and associated toxin to capture food, although none is known actually to pursue prey. Sessile polyps depend for food on organisms that come into contact with their tentacles.
Where do cnidarians live?
Many thousands of cnidarian species live in the world’s oceans, from the tropics to the poles, from the surface to the bottom. Some even burrow. A smaller number of species are found in rivers and fresh water lakes.
Do arthropods have internal or external fertilization?
All known terrestrial arthropods use internal fertilization. Opiliones (harvestmen), millipedes, and some crustaceans use modified appendages such as gonopods or penises to transfer the sperm directly to the female.
What is external and internal fertilization?
Complete answer: Internal fertilization is the process when the syngamy (union of male and female gamete) occurs inside the female body after insemination using copulation. In contrast, External fertilization is the syngamy outside the female body, that is in the outer environment especially in water bodies.
What organs are found in Cnidaria?
They are the most primitive of animals whose cells are organized into distinct tissues, but they lack organs. Cnidarians have two body forms—polyp and medusa—which often occur within the life cycle of a single cnidarian.
Do arthropods have external fertilization?
Rarely, arthropods do external fertilization, which is when the female releases the egg and the male releases the spermatophore or sperm at the same time to fertilize the eggs outside of the body. This occurs in horseshoe crabs.
Do arthropods have internal fertilization?
Arthropods have an open circulatory system, and separate sexes. Fertilization is usually internal, another adaptation for terrestrial life. Males and females often show pronounced sexual dimorphism.
Where does digestion occur in cnidarians?
Cnidarians perform extracellular digestion, with digestion completed by intracellular digestive processes. Food is taken into the gastrovascular cavity, enzymes are secreted into the cavity, and the cells lining the cavity absorb the nutrient products of the extracellular digestive process.
Do cnidarians move?
How do cnidarians move? Since Cnidarians do not have a mesoderm, they do not have any true muscle. They move by epithelial muscular cells (cells in the epidermis that can contract and are made up myosin and actin.
What did cnidarians evolved from?
However, both cnidarians and ctenophores have a type of muscle that, in more complex animals, arises from the middle cell layer. As a result, some recent text books classify ctenophores as triploblastic, and it has been suggested that cnidarians evolved from triploblastic ancestors.
Is a leech fertilization external or internal?
Leeches carry out a slight variation on this process by using the sperm to fertilize the eggs while they are still within the body. Once they are fertilized, the eggs are then deposited into the cocoon. Therefore, leeches have internal fertilization.
Is the development of a Cnidaria direct or indirect?
Cnidarians and sponges also have their own version of indirect development through non-feeding larval stages (figure 2c).
What is the larva of a cnidarian called?
planula, plural planulae, free-swimming or crawling larval type common in many species of the phylum Cnidaria (e.g., jellyfish, corals, and sea anemones). The planula body is more or less cylindrical or egg-shaped and bears numerous cilia (tiny hairlike projections), which are used for locomotion.
How do medusa reproduce?
In the adult, or medusa, stage of a jellyfish, they can reproduce sexually by releasing sperm and eggs into the water, forming a planula.
How do cnidarians respond to their environment?
Cnidarians lack specific response to external stimuli, such as detecting what direction a stimulus is coming from. However, their stinging cells are regulated in part by their nervous system; these cells play a big part in cnidarian defense and prey capture.
Are cnidarians Diploblastic?
Cnidarians are generally regarded as diploblastic animals, possessing endoderm and ectoderm, but lacking mesoderm.
How do cnidarians excrete waste?
There is no specialised excretory system found in cnidarians. Most of the cnidarians expel their waste out through the body surface by diffusion or through the mouth from the gastro-vascular cavity.
How do cnidarians maintain homeostasis?
Cnidarians secrete hormones from glands that allow them to maintain homeostasis. They use direct diffusion in order to circulate the necessary nutrients through its body.
Which is one characteristic of all cnidarians?
All Cnidarians share particular trait: tentacles with stinging nematocysts. The nematocysts act like tiny harpoons, reacting to stimuli by hurling out small stinging cells that both poison and hook potential prey.
How many tissue layers do cnidarians have?
Most cnidarians have two tissue layers. The outer layer, the ectoderm, has cells that aid in capturing food and cells that secrete mucus. The inner layer, the endoderm, has cells that produce digestive enzymes and break up food particles. The jellylike material between the two layers is called the mesoglea.
Which of the following are not cnidarians?
So, the correct option is ‘Beroe‘.
Is fertilization in molluscs external or internal?
Molluscs have extreme variation in reproductive characteristics. A generic mollusc is dioecious with paired gonads. Eggs or sperm are released into the coelomic cavity and carried outside by ducts. Fertilization is external and the zygote develops into a gastrula and then a free-swimming trochophore larva.
Do mollusks reproduce internally?
Mollusks are primarily of separate sexes, and the reproductive organs (gonads) are simple. Reproduction via an unfertilized gamete (parthenogenesis) is also found among gastropods of the subclass Prosobranchia. Most reproduction, however, is by sexual means.
What type of reproduction do amphibians have?
Amphibians reproduce by laying eggs that do not have a soft skin, not a hard shell. Most females lay eggs in the water and the babies, called larvae or tadpoles, live in the water, using gills to breathe and finding food as fish do. As the tadpoles grow, they develop legs and lungs that allow them to live on land.
What type of reproduction does phylum Mollusca have?
Mollusks reproduce sexually, and most species have separate sexes. Sexual reproduction is achieved by the formation and fusion of gametes: sperm and eggs. Some species are hermaphrodites meaning that individuals are capable of forming both sperm and eggs.
Do cephalopods have internal fertilization?
Fertilization is internal with egg capsules being laid and development is direct. Eggs are large and yolk-rich, and the embryonic development of cephalopods is different from that of all other molluscs. Cephalopods never go through a larval stage, they just develop directly into juveniles.
Are gastropods asexual reproduction?
Some species regularly self-fertilise. Uniparental reproduction may also occur by apomixis, an asexual process. For the most part, however, land slugs do mate: they find partners, and engage in elaborate courtship rituals before actual sperm transfer takes place.
How do arthropods reproduce?
All terrestrial arthropods reproduce by internal fertilization. They do so usually by males producing packets of sperms called spermatophores, which the females take into their bodies. Arthropods usually lay eggs. However, gravid scorpions produce eggs that hatch inside their body.