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Genetic Variation 7

Can natural selection occur if there is no genetic variation? No
What events could trigger the process of natural selection in a species? a change in food supply or a change in climate (Remember the penguins)!
How does the movement of new individuals into a population help bring about evolution? They bring new DNA and increase the possibility of more variations in the population leading to evolution.
What are the four types of fossils? 1) imprint of a leaf or fossil in a rock 2) cast made minerals that filled hollows of an animal track or shell 3) animal frozen in ice 4) an insect or plant trapped in plant resin
Where are fossils found? Fossils are most commonly found in sedimentary rock in particular limestone.
Why is the fossil record incomplete? 1) sedimentary rocks were destroyed or lost 2) Some fossils are now underwater 3) Some organisms are unable to be fossilized 4) Volcanic eruptions destroyed many fossils 5) Many fossils become fossil fuels such as oil or gas
What is an endangered species? so few animals left that they are in danger of becoming extinct
How can extinction be prevented? It may be prevented by breeding endangered animals in captivity
What is the Endangered Species Act (1973) and what is the potential limiting factor? It is a law where remaining individuals of some species are captured and kept in breeding programs. The limiting factor is money.
Why do some people feel that efforts SHOULD be taken to save endangered species? They argue that human’s actions cause rapid changes in the environment that contain species that cannot adapt quickly enough to survive on their own. They feel that extinction of such species is not part of a natural process.
What are the three methods that people have used to develop organisms with desirable traits? selective breeding, cloning and genetic engineering
What is selective breeding? the process of selecting a few organisms with the desired traits to serve as parents of the next generation
What is cloning? has exactly the same genes as the organism from which it was produced
What is genetic engineering? process by which genes from one organism are transferred into the DNA of another organism
What is inbreeding? breeders cross 2 individuals with similar characteristics
What is hybridization? Breeders cross two genetically different individuals to produce an organism with the best traits from both parents
What is gene therapy? Process in which researchers insert working copies of a gene directly into the cells of a person with a genetic disorder
What is the goal of the Human Genome Project? To identify the DNA sequence of every gene in the human Genome (all of the DNA in one cell of an organism)
What is a genetic disorder? an abnormal condition that a person inherits through genes or chromosomes
What causes genetic disorders? mutations, or changes in a person’s DNA & changes in the overall structure or # of chromosomes
What is a pedigree? chart or “family tree” that tracks which members of a family have a particular trait
What is a karyotype? A picture of all the chromosomes in a cell
What is Cystic Fibrosis? Abnormally thick mucus caused by the loss of three DNA bases
What is Sickle Cell? Red blood cells are sickle shaped and have reduced ability to hold O2 caused by co-dominant alleles
What is Hemophilia? Blood clots slowly or not at all due to a missing protein
What is Down Syndrome? Mental retardation and heart defects caused by an extra copy of Chromosome 21
Created by: ireneott