Integration Next week (5/19): Chapter 10.6 – 11 Chapter 10.6 – 11 Grade for graduation class Factors determine the future population size: natality (+), mortality (-), immigration (+), emigration (-) natality (+), mortality (-), immigration (+), emigration (-)

Systems of sexuality in animals Term Form ‧ Gonochorism 雌雄異體 Dioecious male or female Dioecious male or female ‧ Hermaphroditism 雌雄同體 Simultaneous male/ female Simultaneous male/ female Sequential Sequential 。 Protandric 先雄後雌 male → female 。 Protandric 先雄後雌 male → female 。 Protogynous 先雌後雄 female → male 。 Protogynous 先雌後雄 female → male 。 Sequential alternating with sex reversal 。 Sequential alternating with sex reversal

Sex determination of Crepidula sp. (Barnes et al., 1993)

幼體期高死亡率的原因 生物因子 生物因子 捕食 捕食 空間競爭 空間競爭 耐飢力 耐飢力 非生物因子 --- 潮間帶 非生物因子 --- 潮間帶 乾燥 乾燥 溫度 溫度

海洋無脊椎動物幼體期有高死亡率 策略一 : Longer life span 策略一 : Longer life span 策略二 : 提早性成熟 策略二 : 提早性成熟

Marine invertebrate larval development A. Indirect development (metamorphosis is involved) a. Planktotrophic development: e.g. mussel, oyster b. Lecithotrophic development: e.g. Babylonia snail c. Direct release from egg cases: e.g. some snails d. Within-parent direct development: some sea snails B. Direct development: e.g. amphipod, octopus

Settlement and metamorphosis Gregarious settlement Other positive cues (e.g. food) Negative cues (e.g. predator) Passive entrainment Identified chemical cues: proteins, neurotransmitters, polypeptides, polysacchrides, oligopeptides, free fatty acids etc. Application: aquaculture and prevention biofouling.

Advantages of complex life cycle (Barnes et al., 1993) 1. Exploitation of the temporary food resource provided by phytoplanktonic blooms 2. Colonization of new habitats 3. Expansion of geographical range 4. Avoidance of catastrophe associated with local habitat failure 5. Avoidance of local and sib-competition 6. Exposure of diverse offspring to the maximum degree of habitat diversity 7. Avoid inbreeding

Evolution pattern of species with planktotrophic larvae: Geologically long-lived and low extinction rates Low speciation rate Wide distributional range

生命起源自海洋 以脊椎動物的演化為例 以脊椎動物的演化為例 鳥類 鳥類 魚類 兩生類 爬蟲類 魚類 兩生類 爬蟲類 哺乳類 哺乳類

鯨類的反向操作 鯨類的祖先是由陸地回到海洋 是由像牛的中爪獸演化成古鯨 類，再變成現在的鯨類

避免強大的競爭壓力 避免強大的競爭壓力 躲避天敵 躲避天敵 目的