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Graland 7th Sci. U10
Question | Answer |
---|---|
Gene | A section of DNA that “codes” for a specific inherited trait. |
Chromosome | A set of genes (from a few dozen to a few thousand) that are tightly wrapped together into a single, compact package. |
Allele | A version of a gene. |
Dominant Allele | An allele whose effect overpowers the effect of another allele. Typically represented using a capital letter. |
Recessive Allele | An allele whose effect is masked (or hidden) by the effect of another allele. Typically represented using a lowercase letter. |
Incomplete Dominance | When the effects of two alleles blend. |
Codominance | When the effects of two alleles are both displayed at the same time. |
Genotype | The combination of alleles for an inherited trait. |
Phenotype | The physical expression of a gene; the observable trait. |
Mutation | A change in the genetic coding. The change may be harmful, helpful, or have no effect at all. |
What is evolution? | Any change in the genes and phenotypes passed from parents to offspring within a population (i.e. breeding group) across generations. Allows populations to adapt to, and survive, changing environments. |
Why does evolution matter? | Evolution allows populations to adapt to, and survive, changing environments. |
What causes living things to evolve? | Random genetic mutations and The process of natural selection |
What is natural selection? | The idea that the environment presents serious challenges to survival and therefore determines which genes, mutations, and inherited traits are the best for successfully living in a particular place. |
What is microevolution? | Small changes in allele and phenotype frequencies within a population across generations. |
What is macroevolution? | The accumulation of so many new inherited changes within a population across generations that a new species develops. |
When does evolution happen quickly? | When the environment changes suddenly and in major ways making it even more challenging for living things to survive. |
What is geographic speciation? | The development of a new species due to geographic isolation, divergent adaptation, and reproductive isolation |
What is a nucleotide? | Basic structure of DNA (Pentagon, Circle, Rectangle) |
The 3 parts of a nucleotide | Sugar (deoxyribose), Phosphate, and the Base |
Similarities of DNA and RNA | at least one strand, built with nucleotides, A,G,C , helps build proteins |
Length of Human DNA | 6 feet per cell, 60 trillion feet in total (estimated) |
Base pairs in Human DNA | ~3.2 billion |
Number of human chromosomes that each parent passes down | 23 |
Number of alleles per gene inherited | 2 |
What determines how alleles are passed from one human generation to the next? | Chance |
Number of genes in human DNA | 20-25,000 |