What you intend the students to learn about this idea.
Students will learn the history of evolutionary theory, from pre-Darwinism to the introduction of Natural Selection by Darwin, and the impact this has had on society since. Students will gain a thorough understanding of the process of Natural Selection, and know the difference between this and Artificial Selection. Beyond this, students will be taught that Natural Selection does not occur at DNA level, but is the end result of random mutations in genetic information.
Human intervention in evolutionary processes can take one of two forms: (1) Inadvertent effects though changes to ecosystems or the environment (e.g. species extinction or species adaptation to suit a changing environment). Human intervention of evolution acts on most species at some level (pristine habitats are rare). (2) Intentional effects via genetic manipulation (e.g. Natural selection vs. artificial selection, genetic engineering, the development of genetically modified organisms (GMO), and cloning - considered distinct from a GMO because genetic material is copied but not altered).
It is intended that students will engage with the ideas of geological time to the point where they are able to describe the history of biology on earth within the context of geological time. Students will learn about the history of geological dating techniques, and which dating processes are best used in a given situation to provide the most accurate idea of geological age.
Why it is important for students to know this.
It is important that students have a thorough understanding of the mechanics of evolution in the natural world to understand and appreciate the forms and functions observed and perceived across all kingdoms. It is also important for students to understand the impacts that Natural Selection has had on society since its introduction and how this affects our decision making and future path.
As Homo sapiens, we are the first species to have an awareness and subsequent control over our evolutionary trajectory and that of species around us. Understanding the cause and effect (in evolutionary terms) of our existence on ourselves and our environment is essential for us to make informed decisions on a range of issues (e.g. maintaining biodiversity, introduction of GMO into the environment etc.)
Without a thorough understanding of geological time, students will be unable to place evolutionary theory in the correct context. It is therefore vital that students understand the geological timescale and its associated dating techniques.
What else you know about this idea (that you do not intend students to know yet).
Students do not need to know the more complex chemical equations at the molecular level, but everything else related to Natural Selection is pertinent.
Bioethics in reality is a ‘big idea’ in its own right, however, I believe the study of human intervention is incomplete without its inclusion. The topic of technological and cultural (superorganic) evolution should also be deferred as it is such a different concept to what biologists would usually consider ‘evolution’, I would defer broaching this subject until I was confident that students had solid understanding of ‘classic’ evolutionary concepts and anthropogenic effects.
Students are not required to have a thorough knowledge of the geological timescale boundaries (i.e. Paleolithic, Cambrian etc), unless the boundaries are relevant to a particular topic of study, such as an extinction event or appearance/disappearance of a particular group of organisms.
Knowledge about students’ thinking /difficulties connected with teaching this idea.
Students may be challenged by the idea that there is no foresight in evolution, and that the selection process itself is based on random DNA mutations. It may be difficult for students to understand the large and small scales involved (DNA to organism size, for instance), and the role which the geological timescale plays in evolution.
When studying human intervention, there is a tendency for humans to see themselves as presiding over evolution and somehow separate from it. “It is [however] impossible to separate man from nature, just as it is impossible to separate mankind from the evolutionary process”. (Dobzhansky, et.al, 1977). Another common alternative conception is that the process of evolution has occurred up until the present time and that we now find ourselves at the end of evolution.
It is extremely difficult to comprehend the vast expanses of time when studying geological time, and students will likely find aspects of this difficult. Though dating techniques are often difficult to grasp, exposure to this topic at lower school levels will have provided students with the opportunity to be acquainted with some of the main ideas of geological dating.
Teaching procedures (and particular reasons for using these to engage with this idea).
An initial class conversation will be conducted to cover the history and impact of Natural Selection. The following lessons will be largely theory based, with a large amount of engagement with students ideas and perceptions. Solid theory is, in my opinion, the best way to really get into learning about Natural Selection, for there is so much information to cover. A number of pracs will also be conducted to demonstrate the mechanics of Natural Selection and to facilitate student engagement with the topic. These include: Learning Activity (1) Learning Activity (2)
Teaching procedures designed to help overcome this could examine, for example, the evolutionary path of Homo sapiens and use this information to identify some possible trajectories for the future path of human evolution. These include: Learning Activity (6) Learning Activity (7) Students should also explore human intervention in evolution and actively debate the associated ethical issues. See: Learning Activity (8) Learning Activity (9)
Practical activities which focus on scaled geological time are extremely useful for students to improve their understanding of the geological timescale in the context of biological evolution. As such, a prac at the very beginning of a 'big idea' will serve to be a context within which to place evolutionary theory, and an excersise to refer back to during the area of study. Students find such pracs to be very eye-opening and surprising, and definately helps them grasp concepts. See: Learning Activity (3) Learning Activity (4)
Also, an excursion to observe geological features (such as chronological strata) will help to give students an idea of the vast amounts of time involved in evolution and link theoretical concepts to real-world situations. See: Learning Activity (5)
Specific ways of ascertaining students’ understanding or confusion around this idea (include likely range of responses).
The initial class conversation, as well as constant interaction with students, will provide feedback as to what the students are having a difficult time understanding. If I believe a concept requires more attention, the class can be re-worked to try and provide students with a clear picture of Natural Selection. A questionnaire (it could even be anonymous) could be a good way to regularly check on students understanding.
Informal assessment of class debate. The discussion of ethical issues raises an interesting point with assessment as there is no right or wrong answer to an issue, only points of view. By allowing students to argue a viewpoint as part of an ethical debate provides them the opportunity to both explore and demonstrate their understanding of ethics in biology. The complex interactions between human, technological and cultural evolution and their effects on evolutionary processes make this a rich topic to explore in this manner. Further, students understanding can also be assertained through the formal assessment of other learning activities.
Confusion about many aspects of geological time will likely be included in students' misunderstanding including where it begins and ends, the vast amounts of time it covers, spatial information about rock strata and the technical aspects of dating proceedure where actual dating is favoured over relative dating. Continuous class discussions and teacher/student intereaction will provide useful feedback of students' understanding in this regard and, of course, engagment with learning activities and their formal assessment will be an accurate measure of student understandings also.
(1) Inadvertent effects though changes to ecosystems or the environment (e.g. species extinction or species adaptation to suit a changing environment). Human intervention of evolution acts on most species at some level (pristine habitats are rare).
(2) Intentional effects via genetic manipulation (e.g. Natural selection vs. artificial selection, genetic engineering, the development of genetically modified organisms (GMO), and cloning - considered distinct from a GMO because genetic material is copied but not altered).
/difficulties connected with teaching this idea.
(and particular reasons for using these to engage with this idea).
These include:
Learning Activity (1)
Learning Activity (2)
Learning Activity (6)
Learning Activity (7)
Students should also explore human intervention in evolution and actively debate the associated ethical issues. See:
Learning Activity (8)
Learning Activity (9)
Learning Activity (3)
Learning Activity (4)
Also, an excursion to observe geological features (such as chronological strata) will help to give students an idea of the vast amounts of time involved in evolution and link theoretical concepts to real-world situations. See:
Learning Activity (5)
(include likely range of responses).