Search results
Results From The WOW.Com Content Network
Reproduction completes and perpetuates the cycle. In biology, a biological life cycle (or just life cycle when the biological context is clear) is a series of stages of the life of an organism, that begins as a zygote, often in an egg, and concludes as an adult that reproduces, producing an offspring in the form of a new zygote which then ...
Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. [6][7] Sexual reproduction also occurs in some unicellular eukaryotes. [2][8] Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such as bacteria and archaea.
Over 1.5 million living animal species have been described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from 8.5 μm (0.00033 in) to 33.6 m (110 ft).
Life history theory (LHT) is an analytical framework [1] designed to study the diversity of life history strategies used by different organisms throughout the world, as well as the causes and results of the variation in their life cycles. [2] It is a theory of biological evolution that seeks to explain aspects of organisms' anatomy and behavior ...
Alternation of generations (also known as metagenesis or heterogenesis) [1] is the predominant type of life cycle in plants and algae. In plants both phases are multicellular: the haploid sexual phase – the gametophyte – alternates with a diploid asexual phase – the sporophyte. A mature sporophyte produces haploid spores by meiosis, a ...
Life cycle of the monarch butterfly. Butterflies in their adult stage can live from a week to nearly a year depending on the species. Many species have long larval life stages while others can remain dormant in their pupal or egg stages and thereby survive winters. [36] The Melissa Arctic (Oeneis melissa) overwinters twice as a caterpillar. [37]
Thus, a cycle may be short, totaling approximately 3 weeks. [21] Horses mate in spring and summer; autumn is a transition time, and anestrus occurs during winter. A feature of the fertility cycle of horses and other large herd animals is that it is usually affected by the seasons. The number of hours daily that light enters the eye of the ...
Jellyfish, also known as sea jellies, are the medusa -phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals, although a few are anchored to the seabed by stalks rather than being motile. They are made of an umbrella-shaped main body made of ...