Reproduction in animals

More • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • How Animals Reproduce What is Reproduction? Reproduction is the process of producing individuals of the same kind. Most organisms reproduce by mating, which increases the genetic variability of the organism. The males and females have separate reproductive organs known as gonads. These gonads produce gametes that fuse together to form a single cell called the zygote. Few animals such as earthworms, snails, slugs, etc. are hermaphrodites and possess male and female reproductive organs in the same organism. Also Read:Â Table of Contents • • • • • • • • • Modes of Reproduction Depending on the number of parents involved, there are different modes of reproduction. In animals is two types of reproduction: • Sexual Reproduction. • Asexual Reproduction. Also Read: Let us g...

reproduction, process by which organisms replicate themselves. In a general sense reproduction is one of the most important At its lowest level, therefore, reproduction is chemical replication. As evolution progressed, cells of successively higher levels of Levels of reproduction Molecular The characteristics that an organism Biology Bonanza The double helices duplicate themselves by separating at one place between the two strands and becoming progressively unattached. As one strand separates from the other, each acquires new complementary bases until eventually each strand becomes a new double helix with a new complementary strand to replace the original one. Because adenine always falls in place opposite thymine and guanine opposite cytosine, the process is called a Molecular reproduction The sequence of bases in a DNA Get a Britannica Premium subscription and gain access to exclusive content. The chemical constituents of cytoplasm (that part of the cell outside the nucleus) are not resynthesized from DNA every time a cell divides. This is because each of the two daughter cells formed during cell division usually inherits about half of the cellular material from the mother cell (see Cells of higher organisms contain complex structures, and each time a cell divides the structures must be

Scientists have announced the first ever recorded case of a crocodile "virgin birth" after a female that had been isolated for 16 years was discovered with a clutch of eggs. The discovery provides "tantalizing insights" into the evolutionary origins of the trait, potentially shedding light on the reproductive capabilities of dinosaurs, a new study finds. The American crocodile ( Crocodylus acutus) was taken into captivity in 2002 when she was 2 years old and placed in an enclosure at Parque Reptilandia in Costa Rica. She remained alone for the next 16 years. But in January 2018, a clutch of 14 eggs was found in the enclosure. Virgin births, also known as facultative parthenogenesis (FP), is a type of asexual reproduction in species that would normally reproduce sexually. Scientists have documented it in birds, sharks, lizards and snakes in captivity, among other species. Until now, it had never been recorded among Crocodilia — the order that includes crocodiles, alligators, caimans and gharials. Related: Mystery of what, or who, butchered Australian crocodile deepens following discovery of 2nd corpse In a study published on Wednesday (June 7) in the journal Biology Letters, researchers said seven of the 14 eggs produced by the crocodile in Costa Rica were viable. Zoo caretakers incubated these eggs, but they didn't hatch, so after three months, they opened the eggs. The contents of six of the eggs was "not discernable," but one contained a fully-formed, but non-viable fetu...

Learning Objectives By the end of this section, you will be able to: • Describe advantages and disadvantages of asexual and sexual reproduction • Discuss asexual reproduction methods • Discuss sexual reproduction methods • Discuss internal and external methods of fertilization Some animals produce offspring through asexual reproduction while other animals produce offspring through sexual reproduction. Both methods have advantages and disadvantages. Asexual reproduction produces offspring that are genetically identical to the parent because the offspring are all clones of the original parent. A single individual can produce offspring asexually and large numbers of offspring can be produced quickly; these are two advantages that asexually reproducing organisms have over sexually reproducing organisms. In a stable or predictable environment, asexual reproduction is an effective means of reproduction because all the offspring will be adapted to that environment. In an unstable or unpredictable environment, species that reproduce asexually may be at a disadvantage because all the offspring are genetically identical and may not be adapted to different conditions. During sexual reproduction, the genetic material of two individuals is combined to produce genetically diverse offspring that differ from their parents. The genetic diversity of sexually produced offspring is thought to give sexually reproducing individuals greater fitness because more of their offspring may survive and...

Organisms are genetically diverse because of sexual reproduction. Sexual reproduction begins with sperm and egg cells, which are produced through a process called meiosis. These cells are referred to as haploid because they contain half of the number of chromosomes as the parent. In sexual reproduction, a haploidsperm from the male parent fertilizes the haploidegg from the female parent to produce what is called a diploid zygote. Zygote is the technical term for a fertilizedegg. The diploid number of chromosomes is the normal number of chromosomes found in all of the regular cells of an organism. The zygote grows and develops into a new organism. It is genetically different from both parents because half of its chromosomes came from the male parent and half of the chromosomes came from the female parent, giving it a unique combination of genes. Sexual reproduction occurs in both plants and animals. Among plants it is used most notably by flowering plants. The pollen grains of flowers contain the sperm. The vase-shaped female reproductive organ in the base of the flower, or the pistil, contains the eggs. When the pollen grains land on top of the pistil, they make a pathway to the eggs. Each zygote develops into a seed that, when in soil, can grow into a new plant. Sexual reproduction occurs in a variety of ways in animals. In some species, such as fish, the male releases sperm over the eggs after the female has laid them. In other species, such as birds and most mammals—inc...

All animals need to make copies of themselves, or they wouldn't exist anymore. It's what life's all about. Of course they can't just put themselves into a photocopier. Although some very simple kinds of creatures, like bacteria, do simply make copies of themselves. They just divide in two, and that's that. Most creatures have male and female versions though. They can only make a new copy if they mix together males and females. That's what we call mating. Females get pregnant after mating. And if they're insects, or fish, or birds, or reptiles, they lay eggs. Us mammals are unusual though... ...we don't lay eggs. Our females keep their babies inside their own bodies, until they have developed enough to survive in the world. Reproduction To reproduce, animals need a male and female. Together they can create offspring, or babies. Some animals, such as chickens, fish and snakes, lay eggs which contain their offspring. Other animals, including humans, tigers and sheep, grow their babies inside them until they are developed enough to be born.

https://bio.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fbio.libretexts.org%2FBookshelves%2FIntroductory_and_General_Biology%2FBook%253A_General_Biology_(Boundless)%2F27%253A_Introduction_to_Animal_Diversity%2F27.01%253A_Features_of_the_Animal_Kingdom%2F27.1C%253A_Animal_Reproduction_and_Development \( \newcommand\) • • • • • • • Most animals undergo sexual reproduction and have similar forms of development dictated by Hox genes. Key Points • Most animals reproduce through sexual reproduction, but some animals are capable of asexual reproduction through parthenogenesis, budding, or fragmentation. • Following fertilization, an embryo is formed, and animal tissues organize into organ systems; some animals may also undergo incomplete or complete metamorphosis. • Cleavage of the zygote leads to the formation of a blastula, which undergoes further cell division and cellular rearrangement during a process called gastrulation, which leads to the formation of the gastrula. • During gastrulation, the digestive cavity and germ layers are formed; these will later develop into certain tissue types, organs, and organ systems during a process called organogenesis. • Hox genes are responsible for determining the general body plan, such as the number of body segments of an animal, the number and placement of appendages, and animal head-tail directionality. • Hox genes, similar across most animals, can turn on or off other genes by coding transcription factors that control the e...

animal reproductive system, any of the The role of This article describes the reproductive systems in metazoans (multicelled animals) from sponges to see Unlike most other organ systems, the reproductive systems of higher animals have not generally become more complex than those of lower forms. A direct relationship exists between behaviour and the functional state of gonads. Reproductive behaviour induced principally but not exclusively by organic substances called Individuals of a species must congregate at the time the gonads contain mature gametes. This often entails Get a Britannica Premium subscription and gain access to exclusive content. Individuals with gametes ready to be shed must recognize members of the opposite sex. Recognition is sometimes by external appearance or by chemical substances ( Geographical The building of When When fertilization is internal, willingness of the female to mate is often essential. Female mammals not in a state of willingness to mate not only will not mate but may injure or even kill an aggressive male. The unwillingness of a female mammal to mate when mature eggs are not present prevents loss of sperm needed to preserve the species. Parental care of fertilized eggs by one parent or the other has evolved in many species. Parental behaviour includes fanning the water or air around the eggs, thereby maintaining Some species extend parental care into the postnatal period, feeding and protecting the offspring. Such behaviour patterns ar...

\( \newcommand\) • • • • • • • • • • • • • • Some animals produce offspring through asexual reproduction while other animals produce offspring through sexual reproduction. Both methods have advantages and disadvantages. Asexual reproduction produces offspring that are genetically identical to the parent because the offspring are all clones of the original parent. A single individual can produce offspring asexually and large numbers of offspring can be produced quickly; these are two advantages that asexually reproducing organisms have over sexually reproducing organisms. In a stable or predictable environment, asexual reproduction is an effective means of reproduction because all the offspring will be adapted to that environment. In an unstable or unpredictable environment, species that reproduce asexually may be at a disadvantage because all the offspring are genetically identical and may not be adapted to different conditions. During sexual reproduction, the genetic material of two individuals is combined to produce genetically diverse offspring that differ from their parents. The genetic diversity of sexually produced offspring is thought to give sexually reproducing individuals greater fitness because more of their offspring may survive and reproduce in an unpredictable or changing environment. Species that reproduce sexually (and have separate sexes) must maintain two different types of individuals, males and females. Only half the population (females) can produce the...

Main article: The first Biologists studying Maintenance of sexual reproduction has been explained by theories that work at several [ citation needed] However, newer models presented in recent years suggest a basic advantage for sexual reproduction in slowly reproducing Sexual reproduction allows these species to exhibit characteristics that depend on the specific Further information: The vast majority of fish species lay eggs that are then fertilized by the male. Some fish species use internal fertilization and then disperse the developing eggs or give birth to live offspring. Fish that have live-bearing offspring include the Poecilia formosa mate with males of other fish species that use internal fertilization, the sperm does not fertilize the eggs but stimulates the growth of the eggs which develops into embryos. Main article: Animals have life cycles with a single diploid multicellular phase that produces haploid gametes directly by meiosis. Male gametes are called sperm, and female gametes are called eggs or ova. In animals, fertilization of the ovum by a sperm results in the formation of a diploid zygote that develops by repeated mitotic divisions into a diploid adult. Plants have two multicellular life-cycle phases, resulting in an Flowering plants Bacteria and archaea Three distinct processes in Bacterial transformation involves the On the other hand, bacterial conjugation is a type of direct transfer of DNA between two bacteria mediated by an external appendage cal...