How Humans Change Traits - Middle School Life Science
- What is gene editing (for example, CRISPR) designed to do to DNA?
- Precisely add, remove, or change specific DNA sequences. Allows targeted genetic changes at specific locations.
- Identify the main goal of selective breeding in crops or livestock.
- To produce offspring with more desirable traits. Improves crops and livestock for human benefit.
- What is heredity?
- Passing genetic information and traits from parents to offspring. How traits are inherited through generations.
- What is a major risk of inbreeding for a population?
- Reduced genetic diversity and increased chance of harmful traits. Less variation makes populations vulnerable to disease.
- What is a common risk of inbreeding?
- Higher chance of harmful recessive traits and genetic disorders. Related parents share more harmful alleles that can pair up.
- What is a trait in genetics?
- A characteristic influenced by genes and often by the environment. Observable features determined by genetics.
- What is a major goal of selective breeding in crops?
- Increase yield, quality, or resistance to pests and disease. Farmers select for traits that improve crop productivity and survival.
- What is a transgenic organism?
- An organism with a gene inserted from a different species. Contains DNA from another species through genetic engineering.
- Which option is an example of selective breeding rather than genetic engineering: Bt corn or dog breeds?
- Dog breeds. Dogs were bred over centuries; Bt corn has inserted bacterial genes.
- What is heterosis (hybrid vigor)?
- Hybrids show stronger growth or health than either parent line. Mixed genetics often produces healthier offspring than pure lines.
- What does selective breeding change in a population over many generations?
- It increases the frequency of alleles for chosen traits. Desired alleles become more common through selection.
- What is selective breeding (artificial selection)?
- Human-directed breeding to increase desired inherited traits. Humans control mating to enhance specific traits over generations.
- Which term describes breeding two different breeds to combine useful traits?
- Crossbreeding. Mixing breeds combines complementary traits from each parent.
- What is one major risk of inbreeding for a population?
- Increased chance of harmful recessive traits appearing. Related parents share more harmful recessive alleles.
- Identify the most likely outcome of repeatedly breeding only the fastest racehorses.
- Average speed increases as speed-related alleles become more common. Selection for speed genes increases their proportion in offspring.
- What is gene editing (for example, CRISPR) used for?
- Making targeted DNA changes, such as adding, removing, or replacing genes. Allows precise modifications to specific DNA sequences.
- Which term describes an organism that contains DNA from another species?
- Transgenic organism. Foreign DNA is inserted to add new traits.
- Which option best describes how selective breeding changes traits: DNA is edited or mating is chosen?
- Mating is chosen; DNA is not directly edited. Selective breeding works through reproduction, not molecular editing.
- What is a key difference between selective breeding and genetic engineering?
- Breeding mixes existing genes; engineering directly alters DNA. Breeding works with natural genes; engineering adds new ones.
- Which outcome is most likely when a population is genetically uniform due to inbreeding?
- Greater vulnerability to disease or environmental change. Low genetic diversity means fewer defenses against threats.
- Identify the key difference between selective breeding and genetic engineering.
- Breeding selects existing variation; engineering directly changes DNA. One works with natural variation, the other creates new genes.
- What is genetic variation, and why does selective breeding require it?
- Differences in genes; it provides traits that can be selected. Without different alleles, there's nothing to select for.
- Which genetic technology is commonly used to copy a gene many times for study?
- PCR (polymerase chain reaction). Amplifies DNA segments for analysis or experimentation.
- Identify the likely result if breeders select only the largest seeds for many generations.
- Average seed size increases in the population. Selecting for a trait shifts the population toward it.
- What is the main goal of selective breeding in plants or animals?
- To produce offspring with specific desired traits more often. Breeders select parents with desired traits to pass them on.
- What is hybrid vigor (heterosis) most directly associated with?
- Crossbred offspring showing improved growth or health. Mixed genetics often produces healthier offspring than purebreds.
- What is hybridization in selective breeding?
- Crossing different varieties to combine desirable traits. Mixing genetic material from different lines creates new combinations.
- Identify the most likely result of repeatedly breeding only the highest milk-producing cows.
- Higher average milk production in the herd over generations. Each generation passes on high-production genes more frequently.
- What is CRISPR most often used for in genetic technology?
- Precisely editing DNA by cutting and altering specific sequences. A tool that cuts DNA at specific locations.
- What is the difference between selective breeding and natural selection?
- Humans choose mates vs. environment favors survival and reproduction. Artificial selection is human-controlled; natural is environment-driven.
- What does GMO stand for in life science?
- Genetically modified organism. Organisms with artificially altered genetic material.
- Identify the best explanation for why purebred lines may have more inherited disorders.
- Reduced genetic diversity increases expression of harmful recessive alleles. Limited gene pool allows harmful alleles to pair up more often.
- What is inbreeding?
- Breeding closely related individuals to increase trait uniformity. Mating relatives concentrates similar alleles in offspring.
- Which term describes breeding closely related organisms to keep desired traits?
- Inbreeding. Mating relatives concentrates shared genes, including desired ones.
- What is cloning in biology?
- Making a genetically identical copy of an organism or cell. Creates exact genetic duplicates without sexual reproduction.
- Identify the genetic technology most suited to turning off one specific gene in an organism.
- Gene editing (such as CRISPR) targeted to that gene. CRISPR can precisely disable specific genes without adding new ones.
- Identify the correct statement about gene editing versus selective breeding for speed of change.
- Gene editing can change traits in one generation; breeding takes many. Direct DNA modification is immediate; breeding requires generations.
- What is a gene?
- A DNA segment that helps determine a trait. Basic unit of heredity that codes for traits.
- Identify the best explanation for why a GMO crop can resist insects.
- It contains a gene that produces an insect-killing protein. The inserted gene codes for a toxin harmful to insects.
- What is artificial selection?
- Human-directed selection of traits, rather than natural selection. Humans choose which organisms reproduce, not environmental pressures.