Download Act. 65 Critter Breeding (KEY)

Lesson 65 – Critter Breeding Packet
Offspring Analysis
Trait
1. Body Segments
2. Legs
3. Eyes
4. Nose
5. Tail Color
6. Tail Style
7. Antennas
Dominant
3 Segments
Blue
Two
Long
Blue
Curly
Two
8. Spikes
1 Short Blue
9. Sex
Male
Medium
2 Long Green
Recessive
2 Segments
Red
Three
Short
Orange
Straight
One
1 Short Blue + 2 Long
Green
Female
Analysis Questions
1. Compare the similarities and differences between the critters (all siblings!) made by your
classmates.
A complete answer will include that there are more critters with the dominant traits above
in table (3 body segments, blue legs, two eyes etc…) than the recessive traits.
2. List the characteristics that show a simple dominant/recessive pattern (like tail color).
Indicate which trait is dominant and which is recessive by underlining the dominant trait.
See the Offspring Analysis chart above – Everything except nose, spikes and sex will
show 3:1 dominance pattern of inheritance.
Some traits do not show a simple dominant vs. recessive pattern. For example, in some plants, a cross
between a red- and white-flowered plant will give pink-flowered offspring. This is called incomplete
dominance. A different example is human blood type. A person with Type A blood and a person with
Type B blood can have a child with type AB blood. This is called co-dominance, as both traits appear in
the offspring.
3. For which characteristics do some offspring have traits in between Skye’s and Poppy’s
traits? Explain which kind of dominance this is.
Nose length is an example of incomplete dominance – medium is in-between long and
short. Medium is the phenotype when the critter is heterozygous (Nn) for nose. (See the
following flower example of incomplete dominance.)
4. For which characteristic(s) do some offspring have both Skye’s and Poppy’s traits?
Explain which kind of dominance this is.
Spikes is an example of co-dominance and you see both traits (short blue and long green)
when heterozygous (GH) for spikes
5. Which critter trait is affected by an environmental factor, such as light, temperature, or
diet? Explain.
Tail style if you have the Ss genotype is affected by diet (critric acid)
6. Consider the pattern for sex determination.
a. How is a critter’s sex determined?
XX is a female and XY is a male and we determined sex of our critter in class with
a toss of the coin for Ocean’s genetic contribution for sex.
b. Whose genetic contribution—Ocean’s or Lucy’s—determines the sex of the
offspring?
Ocean is the male and he contributes either an X chromosome or a Y chromosome
to determine sex of the offspring.
7. Who does your critter most look like –Skye, Poppy, Ocean, or Lucy? On which traits did
you base your choice?
Answers will vary. A complete answer will include at least THREE traits in common
between your critter pup and any one of the parent or grandparent critters
8. Draw a critter with all recessive traits. Assume the recessive trait for spikes is no spikes.
A complete critter drawing will
include:
Trait
1. Body Segments
2. Legs
3. Eyes
4. Nose
5. Tail Color
6. Tail Style
7. Antennas
8. Spikes
9. Sex
Recessive
2 Segments
Red
Three
Short
Orange
Straight
One
None
Female