関連する実験動画
Updated: Jun 24, 2025

06:23
The Polyvinyl Alcohol Sponge Model Implantation
Published on: April 18, 2012
19.8K
エディアカラン後期の冠群のスポンジ動物
Xiaopeng Wang1,2,3, Alexander G Liu3, Zhe Chen1,2
1State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China.
Nature
|June 5, 2024
まとめ
最近発見されたプレカンブリアスポンジの化石 ヘリコロセルス・カントリは 初期のスポンジには有機的な骨格があり 鉱物化したスプキュルが欠けていたことを明らかにしています この発見は 古代のスポンジの生命を 特定する以前の基準に 異議を唱えるものです
科学分野:
- 古生物学
- 進化生物学
- 地質学
背景:
- スポンジは動物進化の初期を理解する上で 極めて重要な基礎的なメタゾーンです
- 分子時計はネオプロテロゾーイクにおけるスポンジの分岐を示唆しているが,カンブリア期以前の化石の証拠は稀である.
- プレカンブリアスポンジは生物鉱物化されていない可能性があり,化石の識別を複雑にしています.
研究 の 目的:
- エディアカール期後半の 新種の化石生物 ヘリコロセルス・カントリーについて
- 前カンブリアスポンジの初期進化と骨格構造を調査する.
- プレキャンブリアス期のスポンジの化石を特定する基準を再評価する.
主な方法:
- デンギング群のヘリコロセルス・カントリの化石の記述と再構築.
- 化石の独特の格子状の有機骨格の分析
- ベイジアン系遺伝分析により,その進化的関係を決定する.
主要な成果:
- ヘリコロセルス・カントリー (Helicolocellus cantori) の発見 骨格がフラクタルでできた大きなコップ状の生物
- 系統遺伝学的分析により,H. cantoriはヘクサチネリダと関連したクラウン群のスポンジに分類される.
- この化石は,プレカンブリア期に有機骨格を持つ 生物鉱物化しないスポンジの存在を 確認している.
結論:
- スポンジは 生物鉱物化以前の オーガニックな骨格で存在していました
- 初期のスポンジの化石を特定する際の普遍的または必要な特徴は,生物鉱物化したスプキュールではないかもしれません.
- この発見は 初期のメタゾウ進化の理解と 化石の識別基準に影響を与えます
関連する概念動画
The Fossil Record
25.1K
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
25.1K
Spongy Bone
4.3K
All bones comprise an outer layer of compact bone, and an interior made up of spongy bone tissue, also called cancellous or trabecular bone. In long bones, spongy bone tissue is mainly found in the interior of the epiphyses (broad ends of the bone).
Spongy bone is more porous, and less dense compared to compact bone. It is composed of concentric lamellae that are arranged irregularly to form the trabecular network. In some bones, the spaces between trabeculae contain red marrow, where...
Spongy bone is more porous, and less dense compared to compact bone. It is composed of concentric lamellae that are arranged irregularly to form the trabecular network. In some bones, the spaces between trabeculae contain red marrow, where...
4.3K
Tooth Anatomy
434
The human tooth enables us to eat a variety of foods, speak clearly, and even aid in shaping our faces. Teeth are composed of various elements that work together. Here's a detailed look at the anatomy of a human tooth.
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or...
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or...
434
Non-vascular Seedless Plants
64.4K
The diverse plant life on Earth—consisting of nearly 400,000 species—can be divided into three broad categories based on biological characteristics: nonvascular, seedless vascular, and seed plants.
64.4K
Cleavage and Blastulation
45.1K
After a large-single-celled zygote is produced via fertilization, the process of cleavage occurs while zygotes travel through the uterine tube. Cleavage is a mitotic cell division that does not result in growth. With each round of successive cell division, daughter cells get increasingly smaller.
45.1K
Keystone Species
21.6K
Measures of species biodiversity, such as richness (i.e., the number of species present) and evenness (i.e., their relative abundance), describe an ecological community’s structure. Many factors affect community structure, including abiotic factors (e.g., sunlight and nutrients), disturbances (e.g., fire or flood), species interactions (e.g., predation or competition), and chance events (e.g., foreign species invasion). Certain species—such as keystone species—also play a...
21.6K

