在埃迪亚卡 - 坎布里亚元元动物中生殖的进化
Rachel A Wood1, Mary L Droser2
1School of Geosciences, University of Edinburgh, James Hutton Road, Edinburgh, EH9 3FE, UK.
概括
埃迪亚卡 - 坎布里亚辐射在元动物繁殖中发生了转变,从幼虫分散和无性生长转向有利于更高后代质量的策略,由增加的掠食和竞争驱动. 这种进化支持了早期动物生命的多样化.
科学领域:
- 古生物学和进化生物学.
- 研究早期的甲动物生命史和生殖策略.
背景情况:
- 生殖风格的进化对元动物生命史至关重要,但在埃迪亚卡拉-坎布里亚时期缺乏整体研究.
- 分子时钟表明Porifera存在于590万年前,主要的eumetazoan群起源于中后期的Ediacaran,以及双边的Ediacaran后期.
- 一个祖先的metazoan特征似乎是一个交替的海底幼虫和盆地成年人生命周期.
研究的目的:
- 整体地探索在埃迪亚卡拉-坎布里亚兴起期间元动物的繁殖方式的演变.
- 分析从化石记录中推断出的生殖策略,跨越不同的埃迪亚卡尔和坎布里亚纪.
- 了解在埃迪卡拉-坎布里亚辐射期间生殖策略转变背后的驱动因素.
主要方法:
- 从埃迪亚卡朗和坎布里亚化石集合 (阿瓦隆,白海等) 推断的生殖风格的汇编和分析. ) 的情况.
- 集成分子钟数据的元动物起源.
- 生殖战略进化与环境和生物变化的相关性,包括生物矿物化和掠食.
主要成果:
- 埃迪亚卡拉社区 (阿瓦隆,白海) 主要利用流传性幼虫进行散播,然后进行无性繁殖 (芽生长,碎片化,裂变).
- 坎布里亚早期的社区表现出越来越多的特有性,热带相互作用,以及诸如内部受精,雄性化,蛋和父母关怀等策略的出现.
- 在埃迪亚卡拉-坎布里亚辐射期间,一些群体发生了向更高生育率和更高质量的后代的显著转变,受到增加的生物相互作用和宏观捕食的影响.
结论:
- 主导的埃迪亚卡拉生殖模式涉及性幼虫,随后是无性生长,在竞争低的环境中促进殖民.
- 坎布里亚时期见证了繁殖策略的多样化,包括内部受精和父母的照顾,以应对不断升级的生物压力.
- 埃迪亚卡拉-坎布里亚辐射的特点是,进化趋势是提高生殖投资,使元动物适应越来越复杂的生态景观.
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