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Key Idea: Similarities and differences in inherited characteristics of organisms alive today or in the past can be used to infer the relatedness of any two species, changes in species over time, and lines of evolutionary descent.

Students are expected to know that:

  1. The similarities among living things suggest relatedness.
  2. The fact that organisms retain some of the inherited characteristics and DNA of their ancestors from many generations ago makes it possible for scientists to identify both recent and past ancestors of those organisms.
  3. Inherited characteristics (both internal and external) of species alive today, including their DNA and the proteins needed to carry out basic life functions, can be compared to determine how similar the species are. Organisms with more similarities are usually more closely related to each other than organisms with fewer similarities, i.e., organisms that have more similarities tend to have a more recent common ancestor than those with fewer similarities.
  4. Inherited characteristics (both internal and external) of species alive today can be compared to the characteristics of species that lived in the past, including their DNA if available and , to determine how similar they are. Organisms with more similarities are usually more closely related to each other than organisms with fewer similarities, i.e., organisms that have more similarities tend to have a more recent common ancestor than those with fewer similarities.
  5. Some structures that do not seem similar in gross structure and function (e.g. the hand of a human and the front flipper of a whale) may after closer analysis of the detailed anatomy and their DNA sequences be shown to have the same origin. A comparison of these homologous structures and the embryonic structures from which they arise can help to infer lines of evolutionary descent.
  6. Many of the same genes code for homologous structures across different species.
  7. The relative ages of fossils can be used to help infer lines of evolutionary descent. Relative ages of fossils are determined by their relative positions in the earth's rock layers.
  8. Fossils, anatomy, and embryos provide corroborative lines of evidence for common ancestry. DNA underlies the similarities and differences in fossils, anatomy, and embryos.
  9. Cladograms and tree diagrams can be used to represent lines of evolutionary descent and to organize hypotheses about the relationships among living things.
  10. Evidence for common ancestry across a wide variety of species provides support for the idea that all multi-cellular organisms (including humans) share a common ancestor. Evidence also indicates that life began as single-celled organisms and that complex multi-cellular organisms evolved from them.
  11. The similarities and differences in all living organisms are explained by their evolution from common ancestors.
  12. Because all organisms share an ancient common ancestor, all organisms, no matter how different they appear to be, have some features in common.

Boundaries:

  1. Students are not expected to know about convergent evolution.
  2. Students are not expected to know about Archae bacteria and the possible multiple origins of life.
  3. Students are not expected to know methods of dating.
  4. Students are not expected to know the approximate date of the origin of life or when any particular species or type of organism originated.
Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID
Number
Knowledge Being Assessed Pre-Test Post-Test (Control) Post-Test (Treatment) Select This Item for My Item Bank

CA017003

Organisms that have more traits in common are also more genetically similar.

80%

88%

89%

CA016003

Organisms that have more traits in common share a more recent common ancestor than organisms with fewer traits in common.

71%

73%

80%

CA034002

Organisms whose DNA sequences for a certain gene are more similar than those of another organism, are also more closely related.

69%

80%

86%

CA040003

Scientists can use similarities in the embryos of two animal species to help determine how closely they are related.

67%

74%

83%

CA011002

If the DNA of Species X and Species Y is more similar than the DNA of Species X and Species Z, then Species X and Species Y have a more recent common ancestor than Species X and Species Z.

63%

72%

81%

CA045002

Recognize evidence and reasoning statements to support the claim that sharks and dolphins share a common ancestor.

60%

64%

67%

CA032003

Different species can have similar genes for similar traits because they inherit them from a common ancestor.

58%

N/A

N/A

CA012001

Identify the diagram that most likely depicts the ancestry of lizards, toads, and dogs if the DNA of lizards and dogs is more similar than the DNA of lizards and toads.

54%

69%

78%

CA015003

Organisms that have more traits in common are probably more closely related than organisms with fewer traits in common.

52%

53%

43%

CA014003

Organisms that have fewer traits in common are probably more distantly related than organisms with more traits in common.

49%

41%

41%

CA043004

Recognize a valid argument that supports the claim that chimpanzees and gorillas have a more recent common ancestry than chimpanzees and orangutans because their average genetic similarity is greater.

48%

56%

61%

CA020003

Organisms that have more traits in common share a more recent common ancestor than organisms with fewer traits in common. (Tree diagram)

47%

N/A

N/A

CA023003

Many of the same genes code for homologous traits (forelimbs) across different species.

47%

60%

53%

CA042002

Similar skeletal features (in dogs and fish) indicate a common ancestor. (Identify claim, evidence, and reasoning.)

47%

41%

43%

CA009004

If the DNA of lizards and dogs is more similar than the DNA of lizards and toads, lizards and dogs share a more recent common ancestor than lizards and toads.

45%

62%

73%

CA024003

Many of the same genes code for homologous traits (forelimbs) across different species.

44%

65%

61%

EN049005

All dogs and cats share a common ancestor.

43%

47%

57%

EN050005

All plants and all animals have a common ancestor with each other.

42%

55%

85%

CA010002

If the DNA of jellyfish and insects is more similar than the DNA of jellyfish and plants, then jellyfish and insects share a more recent common ancestor than jellyfish and insects.

40%

55%

66%

CA026004

Many of the same genes code for homologous traits (forelimbs) across different species.

40%

53%

54%

CA047002

The fact that fish cells and algae both have DNA can be used as evidence that they share a common ancestor. (Identify valid evidence and sound reasoning to support a claim.)

39%

49%

58%

CA041002

Similar skeletal features in organisms (chimpanzees and gorillas) indicate a common ancestor.

39%

49%

46%

EN054002

There are both similarities and differences between maple trees and lizards.

38%

43%

62%

CA006002

Comparing DNA sequences of new strains of the Chikungunya virus to the original strain can be used to determine the DNA sequence of their most recent common ancestor.

36%

45%

46%

CA025002

Many of the same genes code for homologous traits (forelimbs) across different species.

34%

52%

52%

CA031003

Organisms can decode the information in each other's genes to build similar structures (wrists and fingers in mice; bones in the fins of fish).

28%

22%

32%

CA022003

Fossils can be used to determine how closely organisms are related.

19%

26%

36%

CA043005

Write an argument using correct evidence and sound reasoning to support a claim that chimpanzees and gorillas have a more recent common ancestry than chimpanzees and orangutans because their average genetic similarity is greater.

18%

22%

25%

EN046010

Cats, dogs, fish, and birds all share an ancient common ancestor.

12%

31%

46%

EN046012

Chimpanzees, humans, zebras, and worms all share an ancient common ancestor.

10%

22%

41%

EN046011

Chimpanzees, humans, chickens, and oak trees all share an ancient common ancestor.

8%

20%

40%