New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Biological life cycle

A life cycle is a period involving one generation of an organism through means of reproduction, whether through asexual reproduction or sexual reproduction. In regard to its ploidy, there are three types of cycles; haplontic life cycle, diplontic life cycle, diplobiontic life cycle. These three types of cycles feature alternating haploid and diploid phases (n and 2n). The haploid organism becomes diploid through fertilization, which joins of gametes. This results in a zygote which then germinates. To return to a haploid stage, meiosis must occur. The cycles differ in the product of meiosis, and whether mitosis (growth) occurs. Zygotic and gametic meioses have one mitotic stage and form: during the n phase in zygotic meiosis and during the 2n phase in gametic meiosis. Therefore, zygotic and gametic meiosis are collectively term haplobiontic (single mitosis per phase). Sporic meiosis, on the other hand, has two mitosis events (diplobiontic): one in each phase.

Related Stories
 


Plants & Animals News

February 5, 2026

Kemp’s ridley sea turtles, one of the most endangered sea turtle species on Earth, live in some of the noisiest waters on the planet, right alongside major shipping routes. New research reveals that these turtles are especially sensitive to ...
Plants make chemical weapons to protect themselves, and many of these compounds have become vital to human medicine. Researchers found that one powerful plant chemical is produced using a gene that looks surprisingly bacterial. This suggests plants ...
Even in some of the most isolated corners of the Pacific, plastic pollution has quietly worked its way into the food web. A large analysis of fish caught around Fiji, Tonga, Tuvalu, and Vanuatu found that roughly one in three contained ...
As demand for critical metals grows, scientists have taken a rare, close look at life on the deep Pacific seabed where mining may soon begin. Over five years and 160 days at sea, researchers documented nearly 800 species, many previously unknown. ...
SAR11 bacteria dominate the world’s oceans by being incredibly efficient, shedding genes to survive in nutrient-poor waters. But that extreme streamlining appears to backfire when conditions change. Under stress, many cells keep copying their DNA ...
Dinosaur footprints have always been mysterious, but a new AI app is cracking their secrets. DinoTracker analyzes photos of fossil tracks and predicts which dinosaur made them, with accuracy rivaling human experts. Along the way, it uncovered ...
Researchers in Bangladesh have identified a bat-borne virus, Pteropine orthoreovirus, in patients who were initially suspected of having Nipah virus but tested negative. All had recently consumed raw date-palm sap, a known pathway for bat-related ...
A fast-aging fish is giving scientists a rare, accelerated look at how kidneys grow old—and how a common drug may slow that process down. Researchers found that SGLT2 inhibitors, widely used to treat diabetes and heart disease, preserved kidney ...
Small mammals are early warning systems for environmental damage, but many species look almost identical, making them hard to track. Scientists have developed a new footprint-based method that can tell apart nearly indistinguishable species with ...
After analyzing 40 years of tree records across the Andes and Amazon, researchers found that climate change is reshaping tropical forests in uneven ways. Some regions are steadily losing tree species, especially where conditions are hotter and ...
Locust swarms can wipe out crops across entire regions, threatening food supplies and livelihoods. Now, scientists working with farmers in Senegal have shown that improving soil health can dramatically reduce locust damage. By enriching soil with ...
When scientists sent bacteria-infecting viruses to the International Space Station, the microbes did not behave the same way they do on Earth. In microgravity, infections still occurred, but both viruses and bacteria evolved differently over time. ...

Latest Headlines

updated 12:56 pm ET