Study Guide
1. Define heredity. (S7L3a) the passing on of physical or mental characteristics genetically from one
generation to another.
2. Define dominant trait. (S7L3a) a trait that will appear in the offspring if one of the parents
contributes it.
3. Define recessive trait. (S7L3a) Recessive traits can be carried in a person's genes without
appearing in that person.
4. In a sexually reproducing organism, if an adult cell has 46 chromosomes in its nucleus, how
many of these chromosomes will its offspring receive? (S7L3a) 23 Chromosomes
5. What is the difference between genotype and phenotype? (S7L3a)
Phenotype is the
physical expression of the trait (Blue eyes). The genotype is the combination of alleles (rr). Two
organisms can have different genotypes but the same phenotype.
6. What structure carries genes, and where are they located? (S7L3a) Chromosomes, in the nucleus
of cells.
7. How many chromosomes do human body cells have? Human sex cells? Identify each as haploid
or diploid. (S7L3a) Humans have 46 chromosomes in each body cell (diploid), 23 in each sex cell
(haploid).
8. What is the difference between a gene and an allele? (S7L3a) Genes are a segment of DNA that
code for a trait. Alleles are alternate forms of that gene.
9. What are Punnett Squares used for? (S7L3a) The Punnett square is a diagram that is used to
predict an outcome of a particular cross or breeding experiment.
10. List and explain the three types of asexual reproduction.
11. Which type of reproduction results in offspring that are most different from the parent
organisms? (S7L3b) Sexual Reproduction
12. A piece of a geranium plant is cut and placed it in a jar of water in the window. Several weeks
later the piece has grown into a new plant. What is true about the genetic relationship between
the first plant and the new one? (S7L3b) Asexual Reproduction - Budding
13. Everyone in Squidward’s family has light blue skin, which is the dominant trait for body color in
his hometown of Squid Valley. His family brags that they are a “purebred” line. He recently
married a nice girl who has light green skin, which is a recessive trait. Create a Punnett square to
show the possibilities that would result if Squidward and his new bride had children. Use B to
represent the dominant gene and b to represent the recessive gene.
A. List the possible genotypes and phenotypes for their children and complete the Punnett
Square.
B. What are the chances of a child with light blue skin? ____%
C. What are the chances of a child with light green skin? ____%
D. Would Squidward’s children still be considered purebreds? Explain!
14. For thousands of year’s new varieties of plants and domestic animals have resulted from what
process? (S7L3c) Selective Breeding
15. It is very common for yellow labs to have bad hips. This is because owners want purebred yellow
labs who are good hunting dogs. What is this an example of? (S7L3c) selective Breeding
16. All of the following statements are reasons for selective breeding except: (S7L3c)
A. To produce offspring with desirable characteristics
B. Farmers increase their profit by improving crops
C. To improve the quality of food products
D. To increase migration patterns
17. What is the purpose of selective breeding? (S7L3c) To produce a desired genetic outcome for an
organism
18. Use the food web to the right to identify/answer the following questions.
a. Producer(s) (S7L4a):
b. Consumers (S7L4a):
c. How is energy transferred from organisms in this ecosystem? (S7L4a)
d. What do the arrows in a food chain or food web represent? (S7L4a)
e. Where does energy enter this food web? (S7L4a)
f. Example of a predator-prey relationship (S7L4d)
g. Example of organisms which compete with each other (S7L4c)
h. Transfer from producer to consumer (S7L4a)
19. Using the food web to the right, identify a transfer
of matter that goes from consumer to decomposer.
(S7L4a)
20. How does a food chain or food web illustrate the
cycling of nutrients in the environment? (S7L4a)
21. How do decaying organisms affect the health of an ecosystem? How would the complete
removal of decomposers affect an ecosystem? (S7L4a)