Traits and How they change

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Traits and How they change
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Section 1

• Traits- features an organism inherits from its
  parents
• Heredity materials include GENES, part of the DNA
  code on a chromosome
• An organisms genetic makeup is its genotype
• A phenotype is an organisms visible genetic
  makeup and the environments influence on that
  makeup.

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• Environmental effects of phenotypes vary some
  influences are internal while others are external
• Competition for environmental factors have
  significant effects on a population
• An organisms appearance can change based on the
  environment
• Some fish species can change gender in response
  to the ratio of males and females available in
  the population

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• What are some of the phenotypes that can vary due
  to the environment?

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The answer is

• Growth, appearance, gender in certain fish species

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Section 2

• Genetics- the study of heredity
• Gregor Mendel developed principles of genetics by
  experimenting with pea plants
• Different forms of a gene are called an allele
• Dominant alleles show in an organisms phenotype
  whenever present in its genotype

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• Recessive alleles show their effect in an
  organisms phenotype only when two are present in
  the genotype
• Principle of segregation- each parent passes only
  one allele for a trait to its offspring
• Principle of independent assortment- the alleles
  for one trait do not influence the alleles for
  another trait

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• Predicting genetic outcomes- Mendel used
  probability to make predictions
• Reginald G. Punnett developed the Punnett square
  50 years after Mendels work was published
• When the parents genotypes are known, a Punnett
  square is used to predict possible offspring

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• What does the principle of independent
  assortment state?

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The answer is

• Alleles for one trait do not influence alleles
  for another trait

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Section 3

• Over long time periods, the environment impacts a
  species ability to survive
• Nonliving influences include temperature,
  rainfall, fire, elevation, volcanic eruptions,
  periodic flooding and pollution

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• Availability of food, predators, and the number
  of species living in an area affect a species
  survival.
• Darwin and Wallace explain evolution- over time
  environmental factors can change the genetics of
  a species.
• Natural selection- organisms best adapted to
  their environment have a higher rate of survival
  and reproduction than organisms less well adapted

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• Mutation- process in which DNA changes to form
  new alleles
• Selective breeding involves human choice in the
  traits desired in offspring
• Adaptive radiation occurs when one ancestral
  species produces several new species over time
• Extinction- the end of a species, can occur for
  many reasons, including destruction of an
  organisms habitat and the introduction of a new
  species into an environment.

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• How can a mutation influence evolution?

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The answer is

• Offspring with a new, highly desirable trait
  could survive and reproduce more readily than
  offspring without the new trait eventually a new
  species could evolve from the mutated offspring
  with the desirable trait.