VOA科学技术2024--New Research Learns Evolution of Flowering Plants

Flowering plants are very important to Earth's ecosystems². They are necessary for life on Earth.

Flowering plants are also called angiosperms. They are the largest and most diverse plant group. Flowering plants include corn, wheat, rice and potatoes to maple³, oak, apple and cherry trees.

New research based on genome data for 9,506 species of flowering plants provides the deepest understanding yet of their evolutionary⁴ history. The research explains how angiosperms appeared and became widespread during the age of dinosaurs⁵. It also offers explanations for how such plants have changed over time.

The team of scientists created a new tree of life for angiosperms. A tree of life is a tool that biologists use to see the evolutionary relationships among plants, animals and other life forms. Their new tree of life covers 15 times more kinds of flowering plants than the closest comparable study.

"It is a massive leap forward in our understanding of plant evolution," said William Baker⁶. He is a plant expert with the Royal Botanic Gardens, Kew, in London. He is senior writer of the research study, which appeared last week in the publication Nature.

Angiosperms are plants that produce flowers and produce their seeds in fruits. They are made up of about 330,000 species. About 80 percent of the world's plants are angiosperms. They include, among others, all the major food crops, grasses, most large-leaved trees and most aquatic⁷ plants.

Their closest relatives are the gymnosperms, a group that came before them on Earth.

The study identified two periods of diversification⁸ among angiosperms. The first one occurred around 150 million to 140 million years ago during the Mesozoic era. At that time, 80 percent of major angiosperm species arose. The next one happened about 100 million years later during the Cenozoic era, after the extinction⁹ of the dinosaurs and the rise of mammals. That period saw decreasing world temperatures.

Baker said angiosperms are more successful at reproducing than gymnosperms.

Gymnosperms and angiosperms both have seeds. But the flowering plants have enclosed seeds that protect them from dehydration¹⁰. This permits them to survive in a wider range of environments, from deserts to Antarctica.

They also evolved the flower, a structure that permitted them to form relationships with animal pollinators, especially insects. Gymnosperms usually depend upon the wind for pollination¹¹. Angiosperms evolved a high diversity of fruit types, permitting effective seed spread.

Flowering plants provide most of the calories that humans eat, from grains to fruits to vegetables.

"They are sources of many of our medicines and hold potential solutions to global challenges, such as climate change, biodiversity loss, human health, food security and renewable energy," Baker said.

The study could help scientists better understand disease and pest resistance in angiosperms. And the research could help find new medicines.

Alexandre Zuntini is Royal Botanical Gardens botanist¹² and a lead writer of the study. He said that some plant "lineages may hold chemical compounds or even genes¹³ that can be useful for survival of our species."

Words in This Story

ecosystem¹ - n. everything that exists in a particular environment

diverse - adj. different from each other

evolution - n. a theory that the differences between modern plants and animals are because of changes that happened by a natural process over a very long time

leap - n. to suddenly increase by a large amount

aquatic - adj. living or found in or near water

enclose - v. to surround

dehydrate¹⁴ - v. to remove water or moisture from

source - n. someone or something that provides what is wanted or needed

challenge - n. to say or show that may not be true, correct, or legal

botanist - n. a branch of science that deals with plant life

lineage - n. the people who were in someone's family in past times

1 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

2 ecosystems   

n.生态系统( ecosystem的名词复数 )

参考例句：

• There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
• Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样，从雨林到半荒漠等不一而足。 来自辞典例句

3 maple   

n.槭树，枫树，槭木

参考例句：

• Maple sugar is made from the sap of maple trees.枫糖是由枫树的树液制成的。
• The maple leaves are tinge with autumn red.枫叶染上了秋天的红色。

4 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

5 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

6 baker   

n.面包师

参考例句：

• The baker bakes his bread in the bakery.面包师在面包房内烤面包。
• The baker frosted the cake with a mixture of sugar and whites of eggs.面包师在蛋糕上撒了一层白糖和蛋清的混合料。

7 aquatic   

adj.水生的，水栖的

参考例句：

• Aquatic sports include swimming and rowing.水上运动包括游泳和划船。
• We visited an aquatic city in Italy.我们在意大利访问过一个水上城市。

8 diversification   

n.变化，多样化；多种经营

参考例句：

• The seminar was to discuss diversification of agriculture. 该研讨会讨论的是农业多种经营。 来自辞典例句
• Firm diversification is increasingly achieved by the means of takeover and merger. 通过接管和兼并，厂商经营范围日益多样化。 来自辞典例句

9 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。

10 dehydration   

n.脱水，干燥

参考例句：

• He died from severe dehydration.他死于严重脱水。
• The eyes are often retracted from dehydration.眼睛常因脱水而凹陷。

11 pollination   

n.授粉

参考例句：

• The flowers get pollination by insects.这些花通过昆虫授粉。
• Without sufficient pollination,the growth of the corn is stunted.没有得到充足的授粉，谷物的长势就会受阻。

12 botanist   

n.植物学家

参考例句：

• The botanist introduced a new species of plant to the region.那位植物学家向该地区引入了一种新植物。
• I had never talked with a botanist before,and I found him fascinating.我从没有接触过植物学那一类的学者，我觉得他说话极有吸引力。

13 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

14 dehydrate   

vt.使脱水

参考例句：

• People can very quickly dehydrate in the desert.人在沙漠里很快就会脱水。
• Without these structures, many warm-blooded animals would quickly dehydrate,especially in dry climates.没有这样的结构，许多温血动物将很快脱水，特别是在干燥的气候条件下。