动物进化
Section outline
-
What you will learn
::你会学到什么-
How did the
invertebrate
and
vertebrate
evolve
::无脊椎和脊椎动物是如何进化的 -
What were the important
adaptations
in the evolution of animals
::动物进化中的重要适应措施是什么?
What are these? Are these organisms plants, fungi, protists, or animals?
::这些是生物植物,真菌,原生生物,还是动物?This colony of tube resembles the pipes of a musical instrument. These sponges are actually animals, although they are the simplest animals on Earth. Sponges are frequently used as shelter for small crabs, shrimps, and other invertebrates.
::这些海绵实际上是动物,尽管它们是地球上最简单的动物。 海绵经常被用作小螃蟹、虾和其他无脊椎动物的栖身之所。Major Trends in Animal Evolution
::动物演变的主要趋势The oldest animal are about 630 million years old. By 500 million years ago, most modern phyla of animals had evolved. The Figure shows when some of the major events in animal evolution took place.
::最古老的动物有6亿3千万年的历史。到5亿年前,大多数现代动物的植物已经进化。图中显示了动物进化的一些重大事件是何时发生的。Partial Geologic Time Scale. This portion of the geologic time scale shows major events in animal evolution. Animal Origins
::动物起源Who were the ancestors of the earliest animals? They may have been that lived in colonies. Scientists think that of some protist colonies became specialized for different jobs. After a while, the specialized cells came to need each other for survival. Thus, the first multicellular animal evolved. Look at the cells in the Figure . One type of sponge cell, the choanocyte , looks a lot like the protist cell. How does this support the hypothesis that animals evolved from protists?
::最早的动物的祖先是谁? 他们可能是生活在殖民地中的动物。 科学家认为某些原生物群落专门从事不同的工作。 一段时间后, 专门细胞互相需要生存。 因此, 第一种多细胞动物进化了。 看看图中的细胞。 一种海绵细胞, 一种细胞, 看上去非常像原生物细胞。 这如何支持动物从原生物体进化的假设?Choanoflagellate Protist and Choanocyte Cells in Sponges. Sponge choanocytes look a lot like choanoflagellate protists. Evolution of Invertebrates
::无脊椎动物进化Many important animal adaptations evolved in invertebrates. Without these adaptations, vertebrates would not have been able to evolve. They include:
::许多重要的动物适应性在无脊椎动物中演变。如果没有这些适应性,脊椎动物是不可能演变的。它们包括:-
Tissues
,
organs
, and
organ systems
.
::组织、机关和器官系统。 -
A symmetrical body.
::一个对称的身体。 -
A
brain
and sensory organs.
::大脑和感官器官 -
A fluid-filled body cavity.
::装满液体的体腔 -
A
complete digestive system
.
::完整的消化系统 -
A body divided into segments.
::将身体分成几部分
Moving from Water to Land
::从水到土地When you think of the first animals to colonize the land, you may think of . It’s true that ancestors of amphibians were the first vertebrates to move to land. However, the very first animals to go ashore were invertebrates, most likely .
::当你想到第一批殖民土地的动物时,你可能会想到。 诚然,两栖动物的祖先是第一批迁入陆地的脊椎动物。 然而,最先上岸的动物是无脊椎动物,很可能是无脊椎动物。The move to land required new adaptations. For example, animals needed a way to keep their body from drying out. They also needed a way to support their body on dry land without the buoyancy of . One way early arthropods solved these problems was by evolving an exoskeleton . This is a non-bony skeleton that forms on the outside of the body. It supports the body and helps retain water. The ability to breath oxygen without gills was another necessary adaptation.
::迁移到陆地需要新的适应。 例如,动物需要一种方法来防止身体干涸。 它们也需要一种方法来支撑自己在干燥的土地上的身体,而没有浮力。 早期的节肢动物解决这些问题的一个方法就是发展一个外骨骼。 这是在身体外部形成的非骨骼骨骼。 它支持身体,帮助保留水。 呼吸氧气的能力而没有刺刺是另一种必要的调整。Evolution of Chordates
::和弦演变Another major step in animal evolution was the evolution of a notochord . A notochord is a rigid rod that runs the length of the body. It supports the body and gives it shape (see Figure ). It also provides a place for to anchor, and counterbalances them when they contract. Animals with a notochord are called . They also have a hollow nerve cord that runs along the top of the body. Gill slits and a tail are two other chordate features. Many modern chordates have some of these structures only as embryos .
::动物进化的另一个重大步骤是动物进化的进化。 动物进化的另一个重大步骤是动物的进化。 动物进化的进化过程是僵硬的棒,它长着身体的长度。 它支撑身体,并给它形状(见图 ) 。 它也为锚定和在它们收缩时进行平衡提供了一个场所。 动物的进化过程被称为“ 动物进化 ” 。 动物的进化过程还包括一个沿着身体顶部运行的空心神经线。 吉尔的切片和尾巴是另外两个发光的特征。 许多现代的染色板只有作为胚胎才有一些这样的结构。This tunicate is a primitive, deep-sea chordate. It is using its notochord to support its head, while it waits to snatch up prey in its big mouth. Evolution of Vertebrates
::伏变率的演变Vertebrates evolved from primitive chordates. This occurred about 550 million years ago. The earliest vertebrates may have been jawless , like the hagfish in the Figure . Vertebrates evolved a backbone to replace the notochord after the embryo stage. They also evolved a cranium , or bony skull, to enclose and protect the brain.
::活性植物从原始的圆形日期演变而来。这大约发生在5亿5千万年前。最早的脊椎动物可能是没有下巴的,就像图中的长鳍鱼一样。活性动物进化了一个骨骼以取代胚胎阶段之后的未切齿动物。它们还进化了一个头骨,即顶骨,以包围和保护大脑。Hagfish are very simple vertebrates. As early vertebrates evolved, they became more complex. Around 365 million years ago, they finally made the transition from water to land. The first vertebrates to live on land were amphibians. They evolved from lobe-finned fish . You can compare a lobe-finned fish and an amphibian in the Figure .
::随着早期脊椎动物的进化,它们变得更加复杂。大约3.65亿年前,它们终于从水向陆地过渡。第一个生活在陆地上的脊椎动物是两栖动物。它们从白鳍鱼类中演变而来。你可以比较图中叶鳍鱼类和两栖动物。From Lobe-Finned Fish to Early Amphibian. Lobe-finned fish evolved into the earliest amphibians. A lobe-finned fish could breathe air for brief periods of time. It could also use its fins to walk on land for short distances. What similarities do you see between the lobe-finned fish and the amphibian? Evolution of Amniotes
::亚氮的演变Amphibians were the first animals to have true lungs and limbs for life on land. However, they still had to return to water to reproduce. That’s because their eggs lacked a waterproof covering and would dry out on land. The first fully vertebrates were amniotes . Amniotes are animals that produce eggs with internal membranes. The membranes let gases but not water pass through. Therefore, in an amniotic egg , an embryo can breathe without drying out. Amniotic eggs were the first eggs that could be laid on land.
::两栖动物是第一批在陆地上拥有真正的肺部和肢体的动物,然而,它们仍不得不返回水中繁殖。这是因为它们的卵缺乏防水覆盖,而且会在陆地上干涸。第一个完整的脊椎动物是羊膜。 羊膜是产生内膜卵的动物。 膜让气体通过,而不是水通过。 因此,在羊膜卵中,胚胎可以呼吸而不干燥。 羊卵是第一个可以产在陆地上的卵。The earliest amniotes evolved about 350 million years ago. Within a few million years, two important amniote groups evolved: synapsids and sauropsids . Synapsids evolved into mammals . The sauropsids gave rise to , dinosaurs , and .
::最早的安东尼奥在大约3.5亿年前就进化了。在几百万年之内,两个重要的羊群演变了:突触和索罗皮斯。合成人演变成哺乳动物。沙罗皮斯产生了恐龙和恐龙。
Summary
::摘要-
The earliest animals evolved from colonial protists more than 600 million years ago.
::最早的动物起源于6亿多年前的殖民原生主义者。 -
Many important animal adaptations evolved in invertebrates, including tissues and a brain.
::许多重要的动物适应在无脊椎动物中演变,包括组织和大脑。 -
The first animals to live on land were invertebrates.
::第一批在陆地上生活的动物是无脊椎动物。 -
Amphibians were the first vertebrates to live on land.
::两栖动物是第一个生活在陆地上的脊椎动物。 -
Amniotes were the first animals that could reproduce on land.
::亚尼诺是第一批在陆地上繁殖的动物。
Review
::回顾-
List three traits that evolved in invertebrate animals.
::列出无脊椎动物进化的三种特性。 -
Assume that a new species of animal has been discovered. It is an egg-laying animal that lives and reproduces on land. Explain what you know about its eggs without ever seeing them.
::假设已经发现了一种新的动物种类。它是一种产卵的动物, 它在陆地上生存和繁殖。解释你所知道的关于它蛋的事情, 却从未见过它们。 -
Relate similarities between choanoflagellates and choanocytes to animal origins.
::旗和细胞与动物起源的相似性。 -
What was important about the evolution of an exoskeleton?
::外骨骼的进化有什么重要?
-
How did the
invertebrate
and
vertebrate
evolve