During this unit, students consider how different animals, both invertebrate and vertebrate, reproduce, and how traits are passed from parents to offspring. Topics for discussion include the human life cycle and the spectrum of changes that occur during life.
Adolescence is a time of rapid change and development. The changes which puberty brings makes many young people wonder, "What is happening? Am I the only one feeling like this? Do I fit in?" Opportunities for students to discuss change in their lives and see it as a normal occurrence experienced by all maturing organisms are important.
Science writing and reading activities, as discussed in this Guide, should be incorporated into each lesson. Writing reports, letters and stories are only three ways through which students may refine their understanding of the concepts of science and develop their ability to communicate through the written word. Examples of activities which contain writing or reading components are found in the Suggested activities section of this unit.
Science challenge, as described in this Guide, is meant to extend students' critical and creative thinking abilities in the context of the science concepts being studied. Activities involving science challenge should be incorporated into science lessons in each unit. The challenge is intended to give each student a chance to investigate an area of interest in more depth than would be possible for all students in a class to do. Science challenge is a key strategy for bringing the Adaptive Dimension to the classroom, and for encouraging independent learning. The extension phase of each lesson is an ideal place for students to create their own challenge opportunities or to choose from opportunities suggested to them.
Objectives: 1.1, 2.1, 4.1, 4.2
Assessment Techniques: written assignments, presentations, oral assessment
Instructional Method: discussion
Factors: A1, B1, B14,
C2, C3,
E4, G3
Assessment Techniques: group evaluation, observation
checklist, oral assessment
Instructional Methods: conducting experiments, circle of
knowledge
produced? Based on what characteristics of reproduction could
you further subdivide each of the lists?
What advantages and disadvantages are there to each type of
reproduction?
Factors: B4, B14, C2,
C9, F1,
G3
Objectives: 1.3, 2.1,
4.3, 4.4, 5.1
Assessment Techniques: rating scales, observation
checklists, written assignments
Instructional Method: compare and contrast
Analyze the data to determine for which characteristic there is
the most variability in your class and for
which characteristic there is the least variability. Bar graphs
are one way to compare variability of
traits. You will have to make a decision on how you are going to
gauge the variability in each
characteristic. Repeat this process for the other grades you have
surveyed. Is the same characteristic most
variable in each class? Does the amount of variation in each
characteristic stay the same over the eleven
years or does it change? Is there more variation between the male
group and female group within one
class or between members of the same sex in different classes?
Identify other questions to guide analysis
of your data.
On a chart, list characteristics which are variable in one
column and those which are invariable in the
other. For instance, eye colour would go in the variable column
and two arms in the invariable column.
Where would `personality' go? How about `requires water' or
`needs sleep'? Are there more variable or
invariable characteristics among humans?
The example given is for a female student. Her greatgrandparents
are numbered 1 through 8.
Humans have 46 chromosomes. When egg cells and sperm cells are
produced, this number is divided in
half through a process called meiosis, or reduction division.
This is so that when the sperm fertilizes the
egg, the number of chromosomes in the zygote is the normal
number (46).
Cut 23 squares 1 cm on a side from poster board, and label
each square #1, to represent the
chromosomes from the ancestor labelled 1 on the chart. Repeat
this for each ancestor numbered 2
through 8. Keep the squares in separate piles.
Mix the squares labelled #1 with those labelled #2 and then
randomly withdraw 23 squares. The
mixture represents the chromosomes of the son of persons 1 and
2, half coming from his father and half
from his mother. The 23 chromosomes drawn represent the
chromosomes he produced in reduction
division to form a sperm cell.
Mix the piles labelled #3 and #4 and randomly withdraw 23
chromosomes to represent the chromosomes
in an egg cell of the daughter of #3 and #4 ancestors. Mix these
to get the representation of the
chromosomes of your mother. From this group of 46 chromosomes,
withdraw 23 at random, to represent
your chromosomes from your mother's side of the family.
Repeat this whole process with the squares that represent the
chromosomes of persons 5 through 8,
your greatgrandparents on your father's side of the family. From
the #5 and #6 mixture, withdraw 23
and mix with 23 drawn from the #7 and #8 mixture. From those 46,
withdraw 23 at random to
represent the chromosomes from your father's side of the family.
The combination of this group with the
final group of 23 from your mother's side of the family
represent your chromosomes. Draw a bar graph
showing the source of your chromosomes by greatgrandparent. How
does your distribution compare to
the distribution obtained by other members of the class?
Suppose that everyone in the class had the same set of four
grandparents. Is everybody in the class
going to have identical genetic inheritance? What is the chance
that all your chromosomes will come
from greatgrandmother #1 and greatgrandfather #8? Is there any
chance all your chromosomes will come
from greatgrandfather #2 and greatgrandmother #3? Is it possible
that none of your chromosomes came
from either greatgrandfather #2 or greatgrandmother #3?
Suppose that we were to continue labelling the people on this
chart with numbers so that your
grandparents became persons numbered 9 through 12, your parents
are numbers 13 and 14, and you
are #15. Why don't you have any chromosomes labelled #14 and #13
on your bar graph of the pile of
squares representing your chromosomes? Didn't you get your
chromosomes from your parents? Did the
set of chromosomes which you have today originate with your
greatgrandparents, or did they get them
from somebody else?
