Why are fossils considered to be an incomplete record of evolution?
A The fossil record shows changes in kinds of organisms that lived on earth.
B The fossil record shows that many animals are extinct.
C The fossil record is biased for organisms that had hard shells and skeletons.
D Fossils document how new organisms come from preexisting organisms.
The Correct Answer and Explanation is :
The correct answer is C: The fossil record is biased for organisms that had hard shells and skeletons.
Explanation:
Fossils are valuable tools in understanding the history of life on Earth, but they are considered an incomplete record of evolution due to several factors. While fossils do provide significant insight into how organisms evolved over time, they are not a perfect or complete reflection of life’s evolutionary history. The primary reason for this incompleteness is the inherent bias in the fossilization process, which makes some organisms more likely to be preserved than others.
- Bias towards hard-bodied organisms: Organisms with hard shells, bones, or exoskeletons are much more likely to fossilize than those with soft bodies. Soft-bodied organisms, such as jellyfish or worms, decompose quickly and are rarely preserved in the fossil record. In contrast, hard parts like bones, teeth, and shells are much more durable and can survive over long periods, making them more common in the fossil record.
- Incomplete fossilization: Even among organisms with hard parts, the fossilization process is not guaranteed. Fossils are typically formed when organisms are buried quickly by sediments, and only a small percentage of organisms are buried in such a way that they can fossilize. Over time, geological processes can destroy fossils or prevent them from being discovered.
- Temporal gaps: The fossil record is also incomplete in terms of the timeline it covers. Many periods of Earth’s history have few or no fossils due to factors like erosion, the absence of suitable conditions for fossil formation, or the rarity of fossilization events during certain time periods.
Because of these factors, the fossil record can only provide a partial and often biased view of the history of life, which is why it is considered an incomplete record of evolution. While fossils give valuable evidence of evolutionary trends, they cannot capture the full diversity and complexity of life that existed over Earth’s long history.