Why are sea urchins nocturnal?

Sea urchins are mainly nocturnal, and are very sensitive to light. They attach themselves to rocks and hard structures during the day and feed at night. The development of the spines and venom are adaptations the sea urchin perfected over the years to protect them from predation.

Why are these sea urchins sporting cowboy and viking hats there’s science to their hot looks?

There’s Science to Their Hot Looks. After noticing his urchins carrying rocks, shells and even hermit crabs around in his 120 gallon saltwater aquarium, a Colorado aquarium enthusiast started making them custom hats.

Why did internal fertilization likely evolve?

Internal fertilization evolved as a part of the move onto land, as many gametes can’t float through the air in the same way they float through water. Though they usually meet in the female, in some kinds of animals, the egg and sperm meet inside the male.

Why do reptiles have to have internal fertilization?

The offspring develops in the female and is born alive. This occurs in most mammals, some cartilaginous fish, and a few reptiles. Internal fertilization has the advantage of protecting the fertilized egg from dehydration on land. The embryo is isolated within the female, which limits predation on the young.

Why do scientists use sea urchin embryos for fertilization studies?

The species was chosen as a model object for several objective reasons: sea urchins are easy to propagate in the laboratory; it is easy to get synchronous embryo cultures and induce rapid embryogenesis; the embryo is transparent and has a simple structure.

Why do sea urchins reproduce sexually?

They do not show courtship or special behavior towards their mate. Instead, they spawn, meaning that they release their eggs and sperm into the water, reproducing sexually. In particular, Sea Urchins leave reproduction to chance.

Why do we sweat class 7?

Thus, sweating performs two functions: (1) Sweating helps to remove excess water, some salts and a little of urea as liquid waste from the body. (2) Sweating helps to keep our body cool during hot summer days.

Why does external fertilization occur in water?

External fertilisation of the female gamete by the male gamete takes place mostly in water; because water facilitates: extended period of gamete survival and easy movement of sperms towards egg.

Why does external fertilization occurs in water?

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.

Why does external fertilization usually occur in water?

External fertilisation of the female gamete by the male gamete takes place mostly in water; because water facilitates: extended period of gamete survival and easy movement of sperms towards egg.

Why external fertilisation produce more eggs?

External fertilization in an aquatic environment protects the eggs from drying out. Broadcast spawning can result in a greater mixture of the genes within a group, leading to higher genetic diversity and a greater chance of species survival in a hostile environment.

Why is external fertilization disadvantageous to animals than internal fertilization?

Disadvantage if external fertilisation is that there is less chances of meeting of sperm and ova whereas in internal fertilisation there is more chances if fertilisation. More no of sperms are delivered in external fertilisation as compared to internal fertilisation to increase efficiency of fertilisation.

Why is external fertilization important?

External fertilization in an aquatic environment protects the eggs from drying out. Broadcast spawning can result in a greater mixture of the genes within a group, leading to higher genetic diversity and a greater chance of species survival in a hostile environment.

Why is external fertilization more common in aquatic environments?

External fertilisation of the female gamete by the male gamete takes place mostly in water; because water facilitates: extended period of gamete survival and easy movement of sperms towards egg.

Why is external fertilization not possible in organisms that live on land brainly?

Fertilization can’t be external in land animals because land provides a harsh and dry condition which is not suitable for the sperm and egg cells. As we know that sperm have tail to swim in watery condition.

Why is external fertilization not possible on land?

The lack of adequate amount of moisture on land and hence, the lack of survival chances makes it impossible for external fertilization to take place there.

Why is external fertilization unusual for animals that live away from water?

Typically such sperms have one or more flagella and in some species they are streamlined. Hence external fertilization occurs in water. In animals like earthworm external fertilization takes place in cocoon. This doesn’t need presence of water.

Why is external water not essential for fertilization in seed plants quizlet?

Pollen grains are transported by wind or an animal. Why is external water not essential for fertilization in seed plants? There are separate male and female sporophytes.

Why is internal fertilization required for land animals?

Internal fertilization has the advantage of protecting the fertilized egg from dehydration on land. The embryo is isolated within the female, which limits predation on the young. … Fewer offspring are produced through this method, but their survival rate is higher than that for external fertilization.

Why is it advantage for frogs to release large number of eggs and sperm?

Basically, gametes are sex cells. You need sec cells, like sperm and eggs, to reproduce. Frogs, just like many other species, at the foundation of our food chain, produce large quantities of gametes. Evolution has fovored them to do so, to enable them to maintain their population at healthy, stable levels.

Why is it necessary for animals who participate in external fertilization to produce a large number of eggs?

Answer: Organisms that take part in such process produce large number of gametes because (i) In external fertilization, there is a great chance that the sperm and the eggs released by the organisms can be affected by factors present in the environment like dessication ,predators, etc.