Fossil and biological evidence of evolution. Day 1

Internal Module Overview

Module Title: Evidence of Evolution

Lesson: Fossil Evidence of Evolution

Standard: MS-LS4-1

Analyze and interpret fossil record data to document patterns of existence, diversity, extinction, and life form changes on Earth.

Learning Objective:

To explore fossil formation and understand evolution in living organisms.

Skills Developed:

• Explore

• Investigate

• Discuss

• Evaluate

Science Probes: Endless Fossi-bilities

Engagement Activity:

Discussion among four friends about fossils (5 minutes).

• Emma: Views fossils as just pieces of dead organisms with little information.

• Aidan: Believes fossils only derive from extinct animal bones.

• Ethan: Posits that fossils provide evidence of existence through remains or impressions, playing a crucial role in understanding ancient ecosystems.

• Madison: Claims fossils are recent remains that cannot be preserved long, sparking discussions on the preservation conditions that facilitate fossilization.

Task:

Reflect on agreement with one perspective.

Exploration Activity Collaboration:

Team discussion to answer selected questions and utilize resources.

Resources:

• Inspire Book pages 135-139

• YouTube link detailing fossilization processes.

Questions for Exploration:

1. How do fossils form? (2-3 methods)

2. What are the reasons for extinction of living organisms?

3. What are the benefits of discovering the fossil record?

Fossil Formation Process

• Soft Tissue Breakdown: After death, soft tissues are decomposed by bacteria; however, hard parts such as bones and shells may remain intact under ideal conditions.

• Preservation Conditions: Specific, rare conditions such as rapid burial and anoxic environments significantly increase the chances of fossilization.

Types of Fossil Formation:

• Mineralization: Water containing minerals infiltrates the tissues of an organism, replacing the organic material and forming petrified wood or similar structures.

• Carbonization: Over time, pressure expels involved liquids and gases, leaving behind a carbon film, which is often dark in color and represents the original shape of the organism.

• Molds and Casts: Hard sediments can leave a mold of the organism; when that mold is filled with sediment, it becomes a cast that can retain details of the original structure.

• Trace Fossils: These provide evidence of an organism's activities, such as footprints or burrows, highlighting behaviors and interactions with the environment.

• Original Material: Fossils can also form from original tissues preserved in conditions lacking oxygen, such as insects trapped in amber, providing direct insight into the organism's anatomy.

Extinctions and Evolution

Historical Beliefs about Species:

Initial views held that species appeared independently without connections to one another; however, fossil patterns demonstrated relationships among species across geological layers. For instance, studying horse evolution reveals that modern horses share structural similarities with their extinct predecessors, showcasing evolutionary adaptations over time.

Key Concept:

Biological evolution refers to the changes in populations over time, linked by common ancestry, and observable through fossil records.

Reflective Writing Activity Prompt:

Consider your feelings upon finding human fossils; reflect on the lessons we could learn from such poignant discoveries, focusing on humanity's place in Earth's history.

Transitional Fossils and Evolutionary Change

Example of Evolution in Horses:

The evolutionary lineage from Hyracotherium to Equus spans over 55 million years, characterized by adaptations for survival that led to significant morphological changes. Anatomical changes include the development of larger bodies and specialized teeth suited for grazing, illustrating clear evolutionary trends.

Transitional Fossil Defined:

Transitional fossils display characteristics of both ancestral organisms and their evolved descendants, providing crucial insights into the evolutionary process.

Case Study: Tiktaalik roseae

This important transitional fossil illustrates the shift from aquatic to terrestrial life, showcasing features of both fish and early land animals, such as limbs shaped for walking and gills for breathing underwater.

Paleontologist's Role

Paleontologists dedicate their careers to studying fossils, seeking to uncover Earth's extensive biological history. Their work often involves field research in diverse environments to gather fossils and laboratory analysis to determine their significance and implications for understanding the evolution of life.

Evaluation Activity

Three-Dimensional Thinking:

Answer reflection questions about fossil analysis methods and identify patterns that emerge from different fossil records.

Methods of Analysis:

• Relative-age dating: A technique used to determine the age of fossils in relation to one another based on the layers of rock in which they are found.

Patterns for Interpretation:

Generally, younger fossils tend to be found closer to the surface of the Earth, while older specimens lie deeper, thereby helping scientists to map out the history of life on our planet.