2024年3月18日发(作者：钦源)

TPO55 阅读-2 Evolution of the Flowering Plants

原文 .................................................................................................................................................. 1

译文 .................................................................................................................................................. 2

题目 .................................................................................................................................................. 4

答案 .................................................................................................................................................. 7

背景知识........................................................................................................................................... 8

原文

Evolution of the Flowering Plants

①Many aspects of the history of flowering plants (angiosperms) remain

mysterious. Evidence of the earliest angiosperms comes from fossilized leaves,

stems, fruits, pollen, and, very rarely, flowers. In addition, there has been much

study of modern plant morphology (structure) and genetics in order to determine

which living species might be most closely related to the ancient ancestors of

angiosperms. Despite intensive efforts for over 200 years, scientists have still not

reached consensus on which type of plant was the ancestor to the angiosperms,

and when and where the angiosperms first evolved. Indeed, Charles Darwin

himself called the origin of the flowering plants an “abominable mystery.”

②What type of plant was the ancestor to the angiosperms? Most botanists now

agree that the flowering plants are monophyletic in origin, meaning that they

evolved from a common ancestor. Some paleontologists have suggested that the

common ancestor may have been a type of cycad (palmlike tropical plants). Other

paleontologists maintain that the angiosperms may have evolved from

seed-bearing ferns. Finally, analysis of the morphological traits of some primitive

living plants suggests that the ancestor may have been related to the modern pines.

The question of angiosperm ancestry remains unresolved.

③The time and place of the first appearance of flowering plants have long been a

topic of great interest. There is good fossil evidence that early angiosperms,

including a number resembling modern magnolias, were present in the Early

Cretaceous geologic period (more than 100 million years ago). Angiosperms

became increasingly abundant during this period. Between 100 million and 65

million years ago, a period known as the Late Cretaceous, angiosperms increased

from less than 1 percent of flora (plant life) to well over 50 percent. Many of the

modern plant families appeared during this time period. In the Early Tertiary

period which followed, angiosperms increased to comprise 90 percent or more of

1

Earth’s total flora. Where did these successful plants first originate and spread

from?

④Analysis of the fossil leaf structure and geographic distribution of the earliest

Cretaceous angiosperms has led many biogeographers to conclude that they

evolved in the tropics and then migrated poleward. It is known that angiosperms

did not become dominant in the high latitudes until the Late Cretaceous.

Paleontologists have recovered fossil angiosperm leaves, stems, and pollen from

Early Cretaceous deposits in eastern South America and western Africa. These two

continents were joined together as part of Gondwanaland, one of two

supercontinents that existed at that time. The locations of these early angiosperm

finds would have been close to the equator during the Early Cretaceous and are

conformable with a model by which angiosperms spread from the tropics

poleward.

⑤Not all botanists agree with an African-South American center for the evolution

and dispersal of the angiosperms, pointing out that many of the most primitive

forms of flowering plants are found in the South Pacific, including portions of Fiji,

New Caledonia, New Guinea, eastern Australia, and the Malay Archipelago. Recent

genetic research has identified the rare tropical shrub Amborella as being the living

plant most closely related to the ancient ancestor of all the angiosperms. This

small shrub, which has tiny yellow-white flowers and red fruit, is found only on

New Caledonia, a group of islands in the South Pacific. Many botanists conclude

that the best explanation for the large numbers of primitive living angiosperms in

the South Pacific region is that this is where the flowering plants first evolved and

these modern species are relics of this early evolution. Comparisons of the DNA of

Amborella and many hundreds of species of flowering plants suggest that the first

angiosperm arose and the development of separate species occurred about 135

million years ago.

⑥Recently discovered fossils complicate our understanding of the origin of the

angiosperms even further. Paleontologists from China have found beautifully

preserved fossils of an angiosperm plant, including flowers and seeds, in Jurassic

period deposits from China. The site, which is about 130 million years old, is near

modern Beijing. The new fossil plant found at the site is one of the oldest known

angiosperms. The age of the fossils and the very primitive features of the flowers

have led the discoverers to suggest that the earliest flowering plants may have

evolved in northern Asia.

译文

开花植物进化史

2

2024年3月18日发(作者：钦源)

TPO55 阅读-2 Evolution of the Flowering Plants

原文 .................................................................................................................................................. 1

译文 .................................................................................................................................................. 2

题目 .................................................................................................................................................. 4

答案 .................................................................................................................................................. 7

背景知识........................................................................................................................................... 8

原文

Evolution of the Flowering Plants

①Many aspects of the history of flowering plants (angiosperms) remain

mysterious. Evidence of the earliest angiosperms comes from fossilized leaves,

stems, fruits, pollen, and, very rarely, flowers. In addition, there has been much

study of modern plant morphology (structure) and genetics in order to determine

which living species might be most closely related to the ancient ancestors of

angiosperms. Despite intensive efforts for over 200 years, scientists have still not

reached consensus on which type of plant was the ancestor to the angiosperms,

and when and where the angiosperms first evolved. Indeed, Charles Darwin

himself called the origin of the flowering plants an “abominable mystery.”

②What type of plant was the ancestor to the angiosperms? Most botanists now

agree that the flowering plants are monophyletic in origin, meaning that they

evolved from a common ancestor. Some paleontologists have suggested that the

common ancestor may have been a type of cycad (palmlike tropical plants). Other

paleontologists maintain that the angiosperms may have evolved from

seed-bearing ferns. Finally, analysis of the morphological traits of some primitive

living plants suggests that the ancestor may have been related to the modern pines.

The question of angiosperm ancestry remains unresolved.

③The time and place of the first appearance of flowering plants have long been a

topic of great interest. There is good fossil evidence that early angiosperms,

including a number resembling modern magnolias, were present in the Early

Cretaceous geologic period (more than 100 million years ago). Angiosperms

became increasingly abundant during this period. Between 100 million and 65

million years ago, a period known as the Late Cretaceous, angiosperms increased

from less than 1 percent of flora (plant life) to well over 50 percent. Many of the

modern plant families appeared during this time period. In the Early Tertiary

period which followed, angiosperms increased to comprise 90 percent or more of

1

Earth’s total flora. Where did these successful plants first originate and spread

from?

④Analysis of the fossil leaf structure and geographic distribution of the earliest

Cretaceous angiosperms has led many biogeographers to conclude that they

evolved in the tropics and then migrated poleward. It is known that angiosperms

did not become dominant in the high latitudes until the Late Cretaceous.

Paleontologists have recovered fossil angiosperm leaves, stems, and pollen from

Early Cretaceous deposits in eastern South America and western Africa. These two

continents were joined together as part of Gondwanaland, one of two

supercontinents that existed at that time. The locations of these early angiosperm

finds would have been close to the equator during the Early Cretaceous and are

conformable with a model by which angiosperms spread from the tropics

poleward.

⑤Not all botanists agree with an African-South American center for the evolution

and dispersal of the angiosperms, pointing out that many of the most primitive

forms of flowering plants are found in the South Pacific, including portions of Fiji,

New Caledonia, New Guinea, eastern Australia, and the Malay Archipelago. Recent

genetic research has identified the rare tropical shrub Amborella as being the living

plant most closely related to the ancient ancestor of all the angiosperms. This

small shrub, which has tiny yellow-white flowers and red fruit, is found only on

New Caledonia, a group of islands in the South Pacific. Many botanists conclude

that the best explanation for the large numbers of primitive living angiosperms in

the South Pacific region is that this is where the flowering plants first evolved and

these modern species are relics of this early evolution. Comparisons of the DNA of

Amborella and many hundreds of species of flowering plants suggest that the first

angiosperm arose and the development of separate species occurred about 135

million years ago.

⑥Recently discovered fossils complicate our understanding of the origin of the

angiosperms even further. Paleontologists from China have found beautifully

preserved fossils of an angiosperm plant, including flowers and seeds, in Jurassic

period deposits from China. The site, which is about 130 million years old, is near

modern Beijing. The new fossil plant found at the site is one of the oldest known

angiosperms. The age of the fossils and the very primitive features of the flowers

have led the discoverers to suggest that the earliest flowering plants may have

evolved in northern Asia.

译文

开花植物进化史

2