磁気信号は,大規模な補給を誘発する
T Fransson1, S Jakobsson, P Johansson
1Department of Zoology, Stockholm University, SE-106 91 Stockholm, Sweden. thord.fransson@nrm.se
Nature
|November 2, 2001
まとめ
磁気信号は,若い歌う鳥が長い移住旅行に備えるのに役立つかもしれません. シミュレートされた磁場への曝露は,トルス・ナイトガールに脂肪の貯蔵を増やすように促し,砂漠のような生態学的障壁を越えて生存を助けました.
科学分野:
- 鳥類学 鳥類学とは,鳥類学である.
- 動物の移動 動物の移動
- 行動生態学 行動生態学
背景:
- 移動する鳥は,砂漠や海などの燃料補給のできない生態学的障壁を横断するために,脂肪の貯蔵に依存しています.
- 未経験の鳥は,エネルギー備蓄を補充するための重要な停留場所を特定するのに苦労するかもしれません.
研究 の 目的:
- マグネティック・スイッチが,鳥に,大移動の課題の前に脂肪を貯蔵するようシグナルを送ることができるかどうかを判断する.
- 航空航行と資源管理における磁場の役割を調査する.
主な方法:
- スラッシュナイトエンゲル (Luscinia luscinia) は,スウェーデンでの最初の移住前に捕獲されました.
- 鳥たちは,サハラ砂漠の先にあるエジプト北部の停留地をシミュレートした磁場にさらされた.
- シミュレートされた磁場への反応として,脂肪の堆積期間が監視されました.
主要な成果:
- シミュレートされた磁場への曝露は,トルスナイトエンゲルの脂肪沈着期間を大幅に延長しました.
- これは,磁気信号が移住のための生理学的準備を誘発することを示唆しています.
結論:
- 磁気信号は,未経験の移動鳥を,必要不可欠な給油地点に導く上で重要な役割を果たす可能性があります.
- このメカニズムは,小さな歌う鳥が移住中に大きな生態学的障壁をうまくナビゲートし,生き残るのに役立ちます.
関連する概念動画
Magnetic Field Lines
The representation of magnetic fields by magnetic field lines is very useful in visualizing the strength and direction of the magnetic field. Each of the magnetic field lines forms a closed loop. The field lines emerge from the north pole (N), loop around to the south pole (S), and continue through the bar magnet back to the north pole.
Magnetic field lines follow several hard-and-fast rules:
Magnetic field lines follow several hard-and-fast rules:
Magnetic Force On Current-Carrying Wires: Example
In a magnetic field, moving charges encounter a force. If a wire contains these moving charges, i.e., if the wire is carrying a current, then a force acts on the wire as well. Consider a pair of flexible leads holding a wire that is 40 cm long and 10 g in weight in a horizontal position. The wire is placed in a constant magnetic field of 0.40 T, as shown in Figure 1(a). Determine the magnitude and direction of the current flowing in the wire needed to remove the tension in the supporting leads.
Magnetic Flux
The magnetic flux measures the number of magnetic field lines passing through a given surface area. The SI unit for magnetic flux is the weber (Wb). Magnetic flux is a scalar quantity. It depends on three factors: the strength of the magnetic field B, the area through which the field lines pass, and the relative orientation of the field with the surface area.
Suppose a surface is divided into elements of area dA. For each element, the component of the magnetic field that is normal to the...
Suppose a surface is divided into elements of area dA. For each element, the component of the magnetic field that is normal to the...
Magnetic Force
In addition to the electric forces between electric charges, moving electric charges exert magnetic forces on each other. A magnetic field is created by a moving charge or a group of moving charges known as the electric current. A magnetic force is experienced by a second current or moving charge in response to this magnetic field. Fundamentally, interactions between moving electrons in the atoms of two bodies produce magnetic forces between them.
The magnetic force acting on a moving charge...
The magnetic force acting on a moving charge...
Potential Due to a Magnetized Object
Magnetic dipoles in magnetic materials are aligned when placed under an external magnetic field. For paramagnets and ferromagnets, dipole alignment occurs in the direction of the magnetic field. However, the dipoles align opposite to the field in the case of diamagnets. This state of magnetic polarization due to the external field is called magnetization. Magnetization is defined as the dipole moment per unit volume. It plays a similar role to polarization in electrostatics.
The vector...
The vector...
Magnetic Damping
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...


