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:
- The similarities among living things suggest relatedness.
- 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.
- 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.
- 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.
- 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.
- Many of the same genes code for homologous structures across different species.
- 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.
- Fossils, anatomy, and embryos provide corroborative lines of evidence for common ancestry. DNA underlies the similarities and differences in fossils, anatomy,
and embryos.
- Cladograms and tree diagrams can be used to represent lines of evolutionary descent and to organize hypotheses about the relationships among living things.
- 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.
- The similarities and differences in all living organisms are explained by their evolution from common ancestors.
- Because all organisms share an ancient common ancestor, all organisms, no matter how different they appear to be, have some features in common.
Boundaries:
- Students are not expected to know about convergent evolution.
- Students are not expected to know about Archae bacteria and the possible multiple origins of life.
- Students are not expected to know methods of dating.
- 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% | |
Frequency of selecting a misconception
Misconception ID Number |
Student Misconception |
Pre-Test |
Post-Test (Control) |
Post-Test
(Treatment) |
ENM041 |
Species that are similar can share a common ancestor, but species that have no apparent, obvious, or superficial similarities cannot share a common ancestor (Poling & Evans, 2004; Stern & Hagay, 2005). | 59% | 49% | 36% |
ENM051 |
Species that have no apparent, obvious, or superficial similarities have no similarities at all (see Shtulman, 2006). | 37% | 33% | 24% |
ENM058 |
Some species do not share a common ancestor. | 36% | 28% | 19% |
ENM039 |
Plants and animals cannot share a common ancestor (Bizzo, 1994; Ha & Cha, 2008). | 21% | 22% | 7% |
ENM061 |
Completely different genes code for homologous traits across different species. For example, the genes that code for hind legs in cats are in no way similar to the genes that code for hind legs in dogs. (AAAS Project 2061, n.d.) | 14% | 9% | 8% |
ENM059 |
Similarities in DNA do not provide information about whether different types of organisms share a common ancestor (AAAS Project 2061, n.d.). | 13% | 6% | 7% |
ENM054 |
Members of different species do not share a common ancestor (Poling & Evans, 2004; Shtulman, 2006). | 12% | 9% | 6% |
Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.