Common Ancestors
This explains why a fossil snake and a rat both have a quadrate bone.
What is sharing a common ancestor population?
Birds and salamanders both have tails, but they are different because of this.
What is adapting to different environments?
These two species share a more recent ancestor when they have more structures in common.
What is having more shared body structures?
This shows all species in the diagram came from one ancestor.
What is a common ancestor?
Green herons became taller because of this.
What is a change in the environment?
This is why a jumping spider and a fossil eurypterid both have chelicerae.
What is inheriting a structure from a shared ancestor?
Sea anemones and ctenophores both have tentacles, but they differ because of this.
What is natural selection in different environments?
In a diagram, the closest branches show this relationship.
What is being more closely related?
This means two species are more closely related on a diagram.
What is sharing a closer branch?
Chimpanzees became stronger due to this.
What is environmental pressure?
This explains why manta rays and sharks both have cartilage skeletons.
What is descent from a cartilage-skeleton ancestor?
Octopus and surf clam mantles are different because of this reason.
What is adaptation for different survival needs?
Sea lions and zebras are closer to each other than bandicoots because of this.
What is sharing a more recent ancestor population?
This diagram feature shows equal relatedness.
What is equal branch length from the ancestor?
This is NOT a scientific explanation for change.
What is “organisms wanted to change”?
This explains why sea stars and sea urchins share a five-lined body structure.
What is a shared ancestor with radial symmetry?
Tortoise and moray eel jaws differ due to this factor.
What is adaptation to different diets?
Locusts and jumping spiders are more closely related because they share this structure.
What is an exoskeleton?
This shows species do NOT come from separate lines.
What is shared ancestry?
This must happen before traits change.
What is environmental change?
This explains why tortoises and moray eels both have jaws.
What is inheriting jaws from a common ancestor?
This process explains how structures change after populations separate.
What is evolution through natural selection?
This evidence best shows relatedness between fossils and living species.
What is comparative anatomy?
This type of diagram is used to show evolutionary history.
What is an evolutionary tree?
This best explains why traits are stable, then change.
What is natural selection over time?