関連する実験動画
Updated: Jul 12, 2026

04:55
Using a Thermal Camera to Measure Heat Loss Through Bird Feather Coats
Published on: June 17, 2020
まとめ
鳥の巣づくりは,遺伝的適応だけでなく,非遺伝的要因による地域差が顕著である. これは,自然選択のみが鳥の集団における地理的特徴の変動を促すという仮定に異議を唱える.
科学分野:
- 鳥類の生物学について
- 進化生物学の進化生物学について
- エコロジー エコロジー エコロジー
背景:
- 鳥の特徴の地理的多様性は,局所的に適応した遺伝的差異を好む自然選択によって説明される.
- 成鳥で観察されるフェノタイプ的差異は,特定の環境への明確な遺伝的適応から生じると考えられています.
研究 の 目的:
- 鳥の地理的特徴の変動における非遺伝的要因の役割を調査する.
- 非遺伝的影響に起因するニストルの発達における地域差の割合を決定する.
主な方法:
- 地理的に異なる集団 (フロリダ州北部と南部,コロラド州とミネソタ州) の間で赤い翼の黒鳥の卵の実験的交叉飼育.
- 実験操作に関連した現象的差異を評価するために,ニストルの発達を分析する.
主要な成果:
- 赤い翼の黒鳥の巣づくりにおける地域的な変動の有意な部分は,遺伝的ではないことが判明しました.
- 実験的な移植により,遺伝的差異のみではなく,環境的または母性的な影響が,観察された現象型クラインに実質的に貢献することが示されました.
結論:
- 非遺伝的要因は,自然選択とともに,鳥の地理的特徴の多様性を形成する上で重要な役割を果たします.
- 自然選択が成人フェノタイプで観察されたクラインを維持するためには,フェノタイプの変異の遺伝的および非遺伝的成分が共変性を示す必要があります.
関連する概念動画
Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
Types of Selection
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
Mate Choice
Mate choice—the decision about whom to mate with—is a type of natural selection, since animals must reproduce to pass down their genes. Mate choice is also called intersexual selection because the behavior occurs between the sexes.
Limits to Natural Selection
Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.For one, natural selection can only act upon existing genetic variation. Hypothetically, redtusks may enhance elephant survival by deterring ivory-seeking poachers. However, if there are no gene variants—or alleles—for redtusks, natural selection cannot increase the prevalence of...
Morphogenesis
Plant morphogenesis—the development of a plant’s form and structure—involves several overlapping developmental processes, including growth and cell differentiation. Precursor cells differentiate into specific cell types, which are organized into the tissues and organ systems that make up the functional plant.
Frequency-dependent Selection
When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.Positive Frequency-Dependent SelectionIn positive...

