皮层生长标记显示,新西兰摩亚的青少年发育延长
Samuel T Turvey1, Owen R Green, Richard N Holdaway
1School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8020, New Zealand. samuel.turvey@ioz.ac.uk
Nature
|June 17, 2005
概括
已灭绝的莫亚表现出周期性骨生长痕迹,与大多数现代鸟类不同. 这些大型鼠类在十年内达到成熟,这表明与现存的鸟类相比,它们的繁殖时间显著延迟.
科学领域:
- 古生物学的古生物学
- 比较骨科比较骨科
- 进化生物学 进化生物学
背景情况:
- 骨中的循环生长标记在四足动物中很常见,反映了每年的生长模式.
- 鸟类鸟类 (现代鸟类) 通常有缩短的生长周期,使一年一度的骨痕变得罕见.
研究的目的:
- 调查已灭绝的莫阿 (Dinornithiformes) 中皮层骨生长标志的存在和意义.
- 确定moa是否表现出年度增长模式,尽管它们是鸟类.
- 在莫阿家族之间比较生长率和生命史策略.
主要方法:
- 从摩亚长骨中分析皮质骨,以确定周期性生长标志.
- 在Dinornithidae和Emeidae摩阿家族之间的生长模式的比较.
- 评估与身体大小和成熟度相关的生长速度.
主要成果:
- 在莫阿长骨中经常观察到皮层生长标记,这在鸟类中是罕见的发现.
- 莫阿表现出K-选择的生命史特征,一些个体需要近十年才能达到骨成熟.
- 巨型摩亚 (Dinornis) 通过加速幼虫的生长而不是通过延长生长期来达到巨大的尺寸,而不是通过延长生长期,相比较小的雌性摩亚.
结论:
- 莫阿保留了周期性骨沉积的祖先特征,这表明它与典型的鸟类生长模式有所不同.
- 的骨成熟期延长意味着相对于现存的鸟类,繁殖成熟期显著延迟.
- 不同的产后生长率解释了莫阿家族之间的尺寸差异,较大的物种加速了生长.
相关概念视频
02:36Meristems and Plant Growth
Plants grow throughout their lives; this is called indeterminate growth, and it distinguishes plants from most animals. Although certain parts of plants stop growing (e.g., leaves and flowers), others grow continuously—like roots and stems.
01:27Growth of Cartilage and Bone Tissue
Chondrocytes form a temporary cartilaginous model by dividing and secreting a thick gel-like extracellular matrix. Once the chondrocytes undergo programmed cell death, osteoblasts enter the site of the cartilaginous model. The process of replacing the temporary cartilaginous model with bone in an ordered manner is called endochondral ossification. In endochondral ossification, not all of the cartilage is replaced by bone tissue. Some cartilage that performs a protective and supportive function...
01:12Renewal of Skin Epidermal Stem Cells
The skin is divided into epidermis, dermis, and hypodermis, the skin's outermost, middle, and inner layers. The human epidermal layer regularly undergoes renewal, where old, dead cells are replaced by new cells. Epidermal stem cells or EpiSCs divide and differentiate to restore the lost cells. For the renewal process, some EpiSCs continuously self-renew. In contrast, few others differentiate into transit-amplifying cells, which later form prickle or spinous cells, followed by granular cells,...
01:09Changes in the Appendicular Skeleton with Age
The upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after.
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:27Signs of Puberty
Puberty is a critical phase, typically beginning between the ages of 8 and 13 in girls and 9 and 14 in boys, though timing can vary based on genetics, environmental factors, and overall health. This period is characterized by the development of secondary sexual characteristics and the attainment of reproductive potential. Endocrine changes underpin puberty, with hormonal surges of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) instigated by Gonadotropin-Releasing Hormone (GnRH)...
01:18Cognitive Development During Adolescence
During adolescence, individuals experience significant cognitive development that enhances their understanding of others' emotions and thoughts, known as cognitive empathy. This period is marked by an increased ability to adapt to others' perspectives and a more nuanced understanding of others' mental states, a skill that is foundational for social problem-solving and conflict avoidance. The development of cognitive empathy relies heavily on the theory of mind — the recognition that people have...