Unit 1: Biological Diversity - Science 9 Review

Comprehensive vocabulary flashcards covering Topics 4 through 7 of Unit 1: Biological Diversity, including reproduction modes, genetics and inheritance patterns, conservation biology, and selection technologies.

Heritable Traits

Characteristics and traits passed down from parents to their offspring through genes contained within the cell nucleus.

Asexual Reproduction

A mode of reproduction involving only one parent that produces offspring that are identical duplicates, or clones, of the parent organism.

Binary Fission

A form of asexual reproduction utilized by single-celled organisms such as amoebas, in which the cell duplicates its DNA and splits into two identical cells.

Asexual Spores

Single-celled reproductive structures produced by organisms such as fungi that disperse via wind or rain and develop into genetic copies of the parent.

Zoospores

Specialized asexual spores that possess flagella (tail-like structures) to assist in active motility.

Budding

A form of asexual reproduction in small animals such as hydras and sea sponges, where a parent cell grows an outgrowth or bud that detaches once fully developed.

Meristem

Regions of rapidly reproducing, unspecialized cells located at the growing tips of plant stems and roots that facilitate growth, repair, and vegetative reproduction.

Runners

Above-ground horizontal plant stems that extend along the soil surface and develop roots to establish new, genetically identical plant offspring.

Sexual Reproduction

A reproductive strategy involving two parents where offspring inherit $50\%$ of their genetic information from each parent, creating unique genetic diversity.

Gametes

Specialized haploid sex cells (eggs or ova in females, sperm in males) that unite during fertilization.

Zygote

The single, genetically distinct diploid cell produced by the union of male and female gametes during fertilization.

Zygospores

Thick-walled spores formed during sexual reproduction in molds and fungi through the combination and blending of genetic material from two distinct sources.

Bacterial Conjugation

A direct cell-to-cell transfer of genetic material between two bacterial cells that creates novel gene combinations without producing a new cell.

Gymnosperms

Non-flowering seed plants, such as pine, spruce, and fir conifers, that produce uncovered or 'naked' seeds within cones rather than flowers or fruits.

Angiosperms

Flowering plants that produce 'covered seeds' enclosed within fruits following the pollination of ovules by pollen.

External Fertilization

A fertilization process occurring outside the female body in a moist environment, common in fish and amphibians to prevent gametes and zygotes from drying out.

Internal Fertilization

A fertilization process where the union of egg and sperm occurs inside the female organism's body, characteristic of mammals, birds, and insects.

Heredity

The biological transmission of genetic characteristics and traits from parents to their offspring across generations.

Genetics

The branch of biological science dedicated to studying heredity, genes, and the variation of inherited traits in organisms.

Non-Heritable Characteristics

Acquired traits and learned behaviors, such as driving a car, playing an instrument, or dyeing hair, that are developed after birth and cannot be transmitted genetically.

Discrete Variation

Inherited traits that have an 'either/or' distribution with a strictly limited set of possibilities, such as blood type ($A$, $B$, $AB$, $O$) or biological sex.

Continuous Variation

Inherited traits that vary along an unbroken spectrum, caused by the interaction of multiple genes with environmental factors, such as height, hair color, and foot size.

Alleles

The alternate structural forms or variations of a single gene, with organisms possessing two alleles for each inherited trait.

Dominant Trait

A genetic characteristic that is visibly expressed whenever at least one dominant allele is present in the genotype ($BB$ or $Bb$).

Recessive Trait

A genetic characteristic that is only displayed when an individual possesses two copies of the recessive allele ($bb$).

Purebred

An organism whose lineage contains ancestors that have produced only the desired characteristic over generations; also termed homozygous or true-breeding.

Hybrid

An organism produced by crossing two different true-breeding lines, resulting in a heterozygous genotype carrying two different alleles (such as $Bb$).

Punnett Square

A cross-hatched chart used by geneticists to calculate and visualize the probable genotype and phenotype outcomes of a genetic cross between two parents.

Incomplete Dominance

A pattern of inheritance where neither allele is fully dominant or recessive, resulting in an intermediate, blended phenotype such as pink flowers in snapdragons.

Mutation

A change or error in the nucleotide sequence of an organism's DNA induced by environmental mutagens or random cellular errors.

Mutagens

External environmental physical or chemical agents, such as ultraviolet (UV) light and X-rays, capable of altering DNA and causing mutations.

Extinction

The irreversible, complete global loss and cessation of existence of a biological species from planet Earth.

Extirpation

The localized extinction and disappearance of an organism from a specific geographic region, despite the species surviving elsewhere globally.

Indicator Species

Sensitive species, such as large apex carnivores like grizzly bears and wolves, whose population decline or loss signals environmental degradation.

Wildlife Corridors

Protected geographic strips or crossings connecting fragmented habitats, enabling far-ranging wildlife to disperse safely and exchange genetic material.

Seed Banks

Conservation facilities that collect and cryogenically store seeds at below-freezing temperatures to safeguard botanical biodiversity from extinction.

Natural Selection

The evolutionary process proposed by Charles Darwin in 1859 in which environmental conditions favor individuals with advantageous traits, enabling them to survive and reproduce more successfully.

Embryology

The comparative study of prenatal developmental stages across species, providing anatomical evidence of common evolutionary ancestry (such as gills and tails in mammalian embryos).

Artificial Selection

The intentional, human-controlled selective breeding of individual organisms to propagate preferred phenotypic traits at an accelerated rate.

Biotechnology

The technological application of biological systems and living organisms to manufacture agricultural, industrial, or medical commodities.

Cloning

A biotechnological procedure used to generate a genetically identical duplicate of an existing parent cell, plant, or animal.

Artificial Insemination

A reproductive technique in which viable sperm is harvested from a male and mechanically introduced into a female's reproductive tract.

In Vitro Fertilization (IVF)

A laboratory procedure in which both egg and sperm are harvested and joined outside the organism inside a Petri dish to achieve controlled fertilization.

Genetic Engineering

The direct technological modification of an organism's DNA, such as gene splicing to insert foreign genes for medicine or disease resistance.