admin 管理员组文章数量: 1087139
2024年6月17日发(作者：用快速排序排序)
用英语介绍海星六年级
Anatomy:Sea stars are radially symmetrical, and their arms are arranged around a
central disk. Most species have five arms, however sun stars can have as many as 40 arms
or more! Most sea stars are small usually measuring 12-24 cm across, but there are some
species that can be very small or very large. For example, Pycnopodia, the many-rayed
star of the Pacific Northwest can be as big as 1 meter across! The mouth of a sea star is
found in the centre of the underside of the sea star (called the oral surface). Several rows
of tube feet run from the mouth down each arm of the sea star.
These rows of tube feet are guarded by movable spines that line the edges of the
arms for protection. The back side of sea stars can be smooth, spiny, or
nt:Sea stars walk using their tube feet to move themselves along a surface.
Their tube feet have suckers on the ends, which they use to attach themselves to rocks
and to trap prey items.
Sea stars that live on soft surfaces (such as sand) do not have suckers.
These sea star uses their longer tube feet instead, to penetrate into the sand and
other soft g Habits:Most sea stars are carnivores (which means that they
eat other animals) that feed on gastropods, barnacles, sea anemones, sea snails, sea
urchins, bivalves (shellfish) and some times even crabs, dead fish, and other sea stars.
Pretty much any animal they can get their feet on! Instead of their food into their
mouth as we do, sea stars instead flip their stomachs out through their mouth and digest
their prey from the inside out. When the animal is completely digested the stomach is
pulled back into the sea star's uction:Sea stars are dioecious, meaning that
the males and females are in separate individuals, and have as many as ten gonads (two
at the end of each arm)!
Sea stars reproduce by free spawning which means the eggs and sperm are released
into the water from the male and female at the same time. The eggs and sperm then
drift off until they meet up with each other and fertilization occurs. Hundreds of
thousands of larvae are released into the ocean during one breeding season, however a
large portion of these do not survive. As sea star larvae float along through the plankton
they are food to fish and other sea ration:
Sea stars have the remarkable ability to regrow their arms if they are damaged or
eaten by predators. In fact, in some cases an entire sea star can be regenerated from just
a single arm! However, this process is slow and it may take up to a year for a sea star's
arm to grow back to its original common sea star species of the Pacific Coast
are:Dermasterias imbricata:Common name: Leather StarAlternate name:
Garlic StarDescription:The Leather Star is a slimy creature that can be up to 10 inches
in size, most however are only 8 inches across. Leather stars are usually reddish brown
in colour mixed with gray. Often times leather stars can be found with elements of purple
between the red.
This sea star has a strong garlic odour as its alternative name t and
Distribution:Leather stars live in rocky areas of the seashore from Alaska to
interesting facts:Leather Stars cause an extreme response in the sea
anemone, Red Stromphia. When the anemone feels the touch of a Leather Star, it
immediately begins to sway back and forth until its base detaches from the sea floor.
The anemone will "dance" through the water to distance itself from its enemy. Once it
feels it is far enough away from the leather star, it will settle down on the sea floor once
again.
版权声明：本文标题：用英语介绍海星六年级 内容由网友自发贡献，该文观点仅代表作者本人， 转载请联系作者并注明出处：http://roclinux.cn/b/1718623708a724734.html， 本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌抄袭侵权/违法违规的内容，一经查实，本站将立刻删除。
发表评论