4.3.4~4.3.5

For example, China's giant panda is highly endangered because of a combination of habitat loss, low birth rate, and its specialized diet consisting mostly of bamboo. Some shorebirds occupy specialized niches,feeding on crustaceans,insects, and other organisms on sandy beaches and their adjoining coastal wetlands(Figure 4-5).
舉例來說,中國大陸大量的熊貓高度面臨絕種的危機,因為所有棲息地的減少,低出生率,且大多專門以竹子為食.有些水鳥占據特定的,以甲殼鋼動物,昆蟲,和其他在砂質海灘及他們鄰近的海岸濕地的有機體為食.(圖4-5)
In other words, as a result of long-term evolutionary changes each species plays a specific ecological role, called its niche, with generalist species having broad ecological roles and specialist species having narrower ecological roles(Concept4-3).Is it better to be a generalist or a specialist? It depends. When environmental conditions are fairly constant, as in a tropical rain forest, specialist have an advantage because they have fewer competitors.But under rapidly changing environmental conditions, the generalist usually is better off than the specialist.
換言之,結果長期的發展改變每個物種在生態中扮演特定的角色,稱之為"合適的職務",有全科種類有寬闊的生態角色且全科種類有較窄的生態角色(概念4-3).多面的比較好還是專門的比較好呢?答案尚未確定.當環境的條件是公平且不變的,當在一個熱帶雨林,專門的較有利益因為他們有較少得競爭者.但在環境條件快速的改變之下,多面向的通常是比專門的情況較佳的.