Evidence of Evolution 10/27

All living things evolve from one common ancestor. But what evidence do we have of this? How do we know that evolution has actually occurred?

There are several ways to know how evolution has occurred.

- Morphology
- Embryology and development
- The fossil record

Morphology

Morphology is the differences and similarities between living things. ‘Morpho’ is the Latin word for ‘shape’, so morphology (also called comparative anatomy), is the shape of bone structures and their similarities and differences.




This image shows the arm structures of a frog, a lizard, a bird, a cat, a whale, a bat and a human. Based on the similarities and differences, or morphology, in these bone structures, which animal(s) is the human most closely related to here?

Embryology and development

Embryology and development is how things develop before and after birth. While the fetus of a human is still developing, it may look similar to that of a monkey. However, after it is born, more differences begin to appear.




In this image, the pictures colored in blue look the same. The pictures that are yellow, pink or green look different from the blue ones and all the others. You are able to see the similarities in the developing fetuses of a human, a monkey, a pig, a chicken and a salamander. Based on this, which animal do you think is most closely related to the human in this image?

The fossil record

The fossil record is the observations seen of organisms that existed in the past. At this link, we are shown evidence and what it tells us. We can see that the fossil of the curled up trilobite may be trying to protect itself by curling up, similar to today’s pill bugs. Fossils of many of the same organism in some place helps us determine that these organisms may have traveled in packs. Seeing the same fossil on two separate continents may lead to inferences about continental drift. For more information of the fossil record, go here.

S&EP: SP2 Developing and using models

This week, we used to models in the images above to look deeper into the evidence of evolution. The first model had us use colored pencils to color the bones in each organism’s arm structure. This helped up see the bone placement of humans and other organisms. In the second image, we examined the developing fetuses of organisms and looked into the similarities before and after birth. These models helped me see and understand the evidence for evolution. Seeing the similarities between organisms helped support the theory that all living organisms evolved form one common ancestor.

XCC: Patterns
Patterns between organisms help us see the similarities and differences between them. In the first image of the similar bone structures, we can see the organisms more closely related to humans because of their similarities. When we study things like the fossil record, we can connect patterns to study extinct creatures and organisms that may have evolved into modern-day organisms. Trilobites from millions of years ago shared traits with pill bugs from today. We can make predictions that organisms from millions of years ago may have evolved into some of the most common creatures today.