The transition of land plants from water plants and their diversification into the array of vegetation such as simple mosses and liverworts// to towering redwoods has always been an intriguing mystery to scientists.

A research team led by University of Michigan evolutionary biologist Yin-Long Qiu has new findings that help resolve long-debated questions about the origin and evolution of land plants. The work will be published online this week in the Proceedings of the National Academy of Sciences. Two major steps kicked off the chain of events that helped land plants prosper, forming the basis for modern land-based ecosystems and fundamentally altering the course of evolution of life on earth, said Qiu. The first step was the colonization of land by descendents of aquatic plants known as charophyte algae. That event opened up a vast new world where the sun's intensity was undiminished by passage through water and where carbon dioxide—another essential ingredient for plant life—was abundant.

The second event was a key change in plant life cycles. Plants exhibit a phenomenon known as alternation of generations, in which two alternating forms with different amounts of DNA make up a complete life cycle. One form, known as a sporophyte, produces spores, which grow into individuals of the other form, called gametophytes. Gametophytes produce gametes—eggs and sperm—which unite to form a fertilized egg capable of becoming a new sporophyte, thus completing a life cycle. While all plants exhibit alternation of generations, some spend most of their life cycle as sporophytes, and others spend more time in the gametophyte phase.

"Early in the history of plant evolution, a shift occurred," said Qiu, an assistant professor of ecology and evolutionary biology. "If you look at the so-called 'lower' plants such as algae, liverworts and mosses, they spend most of their life cycle as gametophytes. But if you look at plants like ferns, pines and flowering pla
'"/>




Page: 1 2 3
Related medicine news :

1. Sex Played A Vital Role For Evolution Of Infectious Diseases
2. Evolution influenced by Temperature change
3. Scientists Explain Complex Darwinian Evolution
4. The Deadly Evolution of SIV to HIV
5. A Human Brain Gene Could Hold Clues On The Evolution Of Brain Capacity
6. Understanding the Evolution of Viruses a little more Clearly
7. The Evolution of Costly Traits
8. Steps To Improve Quality Of Plant-Based Drugs
9. Common Plant Triggers Asthma
10. Plant sterols found to be effective in Type 2 diabetic patients
11. Plant – based Foods More Effective In Lowering Cholesterol