4.4p69-71

4.4 How do extinction, speciation, and human activities affect biodiversity?

How do new species evolve?
1.天擇nautral selection can lead to an entirely new species call speciation物種形成
2.地理隔離geographic isolation and 生殖隔離reproductive isolation it take tens of thousnads and millions of years.
phase階段,時期

Extinction is forever
3.species that are found in only one area are called endemic species (如golden toad- specialist species)第一個全球暖化的滅絕物種, 減少了森林中的水氣量.
endemic某地特有的
brilliantly燦爛地
toad蟾蜍,癩蛤蟆
lush蒼翠繁茂的

Species become extinct individually and in large groups
4.背景滅絕background exitction as local environmental conditions changs, species disappear at a low rate速率為每年100萬個物種中1-5種消失
5.大滅絕mass extinction 有25-70% species wipe out. 地球經歷5 次mass extinctions during the past 500 million years.
古生代(a. 奧陶紀大滅絕500 million, b. 泥盆紀大滅絕345 million, c. 二疊紀大滅絕250 million), 中生代(d. 三疊紀大滅絕180 million, e. 白堊紀大滅絕65 million)
6.環境改變造成 新物種的產生與舊物種的滅絕 二者的平衡決定了地球的生物多樣性

Human activities can cause the premature extinction of species
7.human have become a major force in the premaute extinction of species物種過早滅絕.
8.decrease the earth's biodiversity a. premature extinction of species, b.destroy or degrade habitats人類佔據太多的地表及淨初級生產力(NPP)
8.exitnction rate increased by 100-1000 times durning 20th century預估2050年會有1/4物種滅絕本世紀末則有1/2物種滅絕
scientific科學上的
consensus輿論
premature過早的
unabated不減弱的
all-out全力以赴
recoup恢復