BIOLOGY EXAM
Heredity — e. The passing of traits from parents to offspring.
Genetics — m. A branch of biology that studies heredity.
Monohybrid cross — c. A cross among one pair of contrasting traits.
True-bred — f. If an individual is true-bred, all of its offspring will display only one form of a trait.
P generation — h. The first two individuals crossed in Mendel's experiments.
F₁ generation — o. Offspring of the P generation.
F₂ generation — k. Offspring in Mendel's experiments that exhibited a 3:1 ratio of dominant: recessive traits.
Alleles — n. Different forms of a gene.
Dominant — g. A form of a trait that overpowers or masks the other.
Recessive — d. A form of a trait that is not expressed when the dominant form is present.
Homozygous — L. A genotype for a trait in which the alleles are the same.
Heterozygous — a. A genotype for a trait in which the alleles are different.
Genotype — p. The genetic makeup of an individual.
Phenotype — i. The physical characteristic of a trait.
Law of Segregation — b. Mendel's law in which the two alleles for a trait separate when gametes are formed.
Law of Independent Assortment — j. Mendel's law in which the alleles of different genes separate independently of one another during gamete formation.
Non-Mendelian Patterns of Inheritance
Polygenic trait:
A trait controlled by two or more genes.Multiple alleles:
A gene that has more than two possible alleles.Codominance:
Both alleles are fully expressed at the same time.Incomplete Dominance:
Neither allele is completely dominant, resulting in a blended trait.X-linked Trait:
A trait carried on the X chromosome.Q. Vestigial structures — The wings of flightless birds, like the ostrich, are an example of this.
V. Biochemistry — Study of nucleic acids and proteins to show evolutionary relationships.
D. Gene flow — Migration.
G. Adaptation — A physical trait that increases an organism's ability to survive in its environment.
N. Mass extinction — Sudden elimination of a species due to a catastrophic event.
K. Punctuated equilibrium — Rapid evolutionary change.
H. Descent with Modification — Biological change over time that causes descendants to be different from their ancestors.
B. Natural selection — Principle of natural selection that explains how beneficial traits become more common over time, causing a change in allelic frequencies.
S. Homologous structures — Body structures that are similar in orientation, but different in function due to organisms living in different environments.
F. Embryology — Study of development in vertebrates that supports common ancestry among vertebrates.
E. Sexual selection — When traits that favor reproduction become more common over time, even if they decrease survival ability.
P. Speciation — When isolation causes two populations to become so different they can no longer reproduce viable offspring.
W. Paleontology — The study of prehistoric life connecting current and extinct species.
M. Divergent evolution — Evolution that results in the formation of homologous structures.
L. Convergent evolution — Evolution that results in the formation of analogous structures.
C. Gene pool — All of the genes available in a population.
J. Gradualism — Slow change in allele frequencies over long periods of time.
A. Evolution — Organisms better adapted to their environment survive and reproduce more successfully.
U. Morphology — Study of body structures to provide evidence of evolution.
I. Fossil — Remnants of organisms such as imprints and bones.
O. Gradual extinction — Slow elimination of species caused by small environmental changes over long periods.
R. Analogous structures — Similar body structures due to organisms living in the same environment, not because of shared ancestry.
T. Biogeography — Study of the physical distribution of plants and animals.
A regular progression of species replacement is known as succession.
Nonliving factors, such as weather, that can affect ecosystems are known as abiotic factors.
The study of living things and their interaction with each other and the environment is known as ecology.
Plants or mosses that first grow in a newly formed ecosystem are called pioneer species.
The variety and genetic differences found within an ecosystem represents the ecosystem's biodiversity.
An ecosystem consists of a community and all of the physical aspects of the habitat.
The biosphere is the portion of the planet that can sustain life.
All the different species that live together in an ecosystem are known as the community.
Succession that occurs in places where there has previously been growth is called secondary succession.
Living factors that are part of the ecosystem are called biotic factors.
Succession that occurs where no soil has existed (no previous growth) is known as primary succession.
A biome is part of the biosphere that has a specific climate and community.
One example of primary succession:
New land formed after a volcanic eruption.
One example of secondary succession:
A forest growing back after a wildfire.
Why are producers essential to an ecosystem?
Producers make food through photosynthesis and provide energy for all other organisms in the ecosystem.
Why are decomposers essential to an ecosystem?
Decomposers break down dead organisms and recycle nutrients back into the environment.