Fossilized stromatolites a. formed around deep-sea vents. b. resemble structures formed by bacterial communities that are found today in some shallow marine bays. c. provide evidence that plants moved onto land in the company of fungi around 500 million years ago. d. contain the first undisputed fossils of eukaryotes.

Verified step by step guidance

1. Step 1: Understand the question. The question is asking about the characteristics of fossilized stromatolites. Stromatolites are layered sedimentary formations that are created by photosynthetic cyanobacteria and other microorganisms. These microorganisms bind and precipitate calcium carbonate, trapping sediment and forming layers as they grow.
2. Step 2: Evaluate each statement individually. Statement a suggests that stromatolites formed around deep-sea vents. This is incorrect, as stromatolites are typically found in shallow marine environments where sunlight, necessary for the photosynthetic cyanobacteria, is available.
3. Step 3: Look at statement b. This statement suggests that stromatolites resemble structures formed by bacterial communities found today in some shallow marine bays. This is correct. Modern stromatolites are found in similar environments, such as the shallow marine bays of Western Australia.
4. Step 4: Consider statement c. This statement suggests that stromatolites provide evidence that plants moved onto land in the company of fungi around 500 million years ago. This is incorrect. Stromatolites do not provide evidence for this specific event in evolutionary history.
5. Step 5: Finally, evaluate statement d. This statement suggests that stromatolites contain the first undisputed fossils of eukaryotes. This is also incorrect. Stromatolites are formed by cyanobacteria, which are prokaryotes, not eukaryotes.

Key Concepts

Stromatolites

Stromatolites are layered sedimentary formations created by the activity of microbial communities, particularly cyanobacteria. These structures are among the oldest evidence of life on Earth, dating back over 3.5 billion years. Modern stromatolites can still be found in shallow marine environments, where they continue to form through similar biological processes.

Fossilization

Fossilization is the process through which organic material is preserved in sedimentary rock, often providing insights into ancient life forms and ecosystems. This process can occur through various mechanisms, including permineralization, where minerals infiltrate and replace organic material, or through the formation of molds and casts. Fossils, including stromatolites, serve as crucial evidence for understanding the history of life on Earth.

Eukaryotes

Eukaryotes are organisms whose cells contain a nucleus and other membrane-bound organelles, distinguishing them from prokaryotes, which lack these features. The emergence of eukaryotes marks a significant evolutionary milestone, as they include all complex life forms, such as plants, animals, and fungi. Fossils of eukaryotes provide critical evidence for the evolution of multicellular life and the diversification of biological forms.