MC Part 1
MC Part 2
MC Part 3
MC Part 4/OE
100
This fossil snake and this living rat both have a structure in their skull called the quadrate bone. What best explains why both species have a quadrate bone?
The snake and rat both share the same ancestor population that had a quadrate bone. They inherited this structure from the ancestor population.
100
This sea anemone and this ctenophore both have tentacles, which are body structures that help them catch food. However, sea anemone tentacles are short and can sting, while ctenophore tentacles are long for grabbing and cannot sting. What most likely explains why both species have tentacles and why the tentacles are different?
Sea anemone and ctenophore both inherited tentacles from a shared ancestor population, but this population separated into different environments. In each environment, different types of tentacles evolved, which helped the populations survive.
100
This echidna, this natterjack toad, and this blue tang have similarities and differences in their body structures. What does the information about these structures tell you about the ancestors of these species?
All three species share an ancestor population, but echidnas and natterjack toads share a more recent ancestor population. This is why they share the neck-bone structure.
100
The body structures for a population of chimpanzees were stable for a long time. Then, their body structures changed, making the chimpanzees stronger. Why did this happen?
Their environment must have changed.
200
This fossil bird and this living salamander both have tails. However, they have different tail structures. The bird has a very short tail made of just one bone that helps it have a light skeleton for flying. The salamander has a long tail with many bones that helps it balance while it runs. What most likely explains why both the bird and salamander have tails and why the tails are different?
The salamander and bird both inherited tails from a shared ancestor population, but this population separated into different environments. In each environment, different types of tails evolved, which helped the populations survive.
200
This red-eared slider, this greater flamingo, and this siamang have similarities and differences in their body structures. What does the information about these structures tell you about the ancestors of these species?
All three species share an ancestor population, but the red-eared slider and the greater flamingo share a more recent ancestor population. This is why they share the egg-laying structure.
200
What does this diagram show?
All three species share a common ancestor, but the bold jumping spider and Bombay locust are more closely related to each other than they are to the common octopus.
200
How could Julio explain why all three species share some body structures and have some differences? Why do only grizzly bears and sea otters have canine teeth?
All three species share structures because they are descendant species of a common ancestor population. This ancestor population passed on the backbone structure to the descendant species. All three also have differences among one another. Their common ancestor population must have separated into different environments where different traits are adaptive in those environments. Over time, the species evolved to become very different from one another.
300
This bandicoot, this sea lion, and this zebra have similarities and differences in their body structures. What does the information about these structures tell you about the ancestors of these species?
All three species share an ancestor population, but sea lions and zebras share a more recent ancestor population. This is why neither shares the pouch structure for their babies.
300
The body structures for a population of green herons (a species of bird that lives near water) were stable for a long time. Then, their body structures changed to make the green herons taller. Why did this happen?
Their environment must have changed.
300
This living sea star and fossil sea urchin both have body structures that are formed along five lines. What best explains why both species have this five-lined body structure?
The sea star and sea urchin both share the same ancestor population that had a five-lined body structure. They inherited this structure from the ancestor population.
400
What does this diagram show?
All three species share a common ancestor, but the Sumatran tiger and Norway rat are more closely related to each other than they are to the African elephant.
400
This living manta ray and this fossil shark both have a skeleton made of cartilage (which is softer than bone). What best explains why both species have a skeleton like this?
The manta ray and shark both share the same ancestor population that had a cartilage skeleton. They inherited this structure from the ancestor population.
400
This tortoise and this moray eel both have jaws that help them grab food. However, they have different structures in their jaws for eating. The tortoise has a bony beak that helps it bite plants. The moray eel has sharp teeth that help it eat fish. What most likely explains why both have jaws and why the jaws are different?
Tortoises and moray eels both inherited jaws from a shared ancestor population, but this population separated into different environments. In each environment, different types of jaws evolved that help the populations survive.
500
This living jumping spider and this fossil eurypterid both have body structures called chelicerae. Chelicerae are a body structure used for eating. What best explains why both species have chelicerae?
The jumping spider and eurypterid both share the same ancestor population that had chelicerae. They inherited this structure from the ancestor population.
500
This octopus and this surf clam both have a body structure called a mantle, which covers their soft bodies. However, the mantle is shaped differently in the two species. The octopus’s mantle has muscles that help the octopus swim. The surf clam’s mantle helps the clam build its shell. What most likely explains why both the octopus and surf clam have mantles and why the mantles are different?
The octopus and surf clam both inherited the mantle structure from a shared ancestor population, but this population separated into different environments. In each environment, different types of mantle evolved, which helped the populations survive.
500
This locust, this jumping spider, and this Roman snail have similarities and differences in their body structures. What does the information about these structures tell you about the ancestors of these species?
All three species share an ancestor population, but locusts and jumping spiders share a more recent ancestor population. This is why they share the exoskeleton structure.