Mighty Mystifying Mutations!

Mutations  A change in genetic material

Background Information…  Mutations can be bad (disadvantageous)  Mutations can be good (advantageous)  Mutations may have no effect

Mutations happen in ALL types of cells.  Body cells- mutations affects the organism only  Sex Cells- Mutations can be passed down to the next generation

Characteristics of mutations.  The earlier a mutation occurs in development, the more an individual is affected  Mutations are random! They cannot be predicted!

Most mutations are recessive.  Two individuals with the same recessive mutation must mate  This may take generations to occur.

Dandy DNA Review  The DNA…  GAT TAC ATT CTA ATG TAA  The mRNA reads it….  CUA AUG UAA  Codons code for amino acids  We use the chart to figure them out  The order of the Amino Acids determines the shape and function of the protein

Types of Mutations  Addition- a base Pair is added  Deletion- a base pair is deleted  Substitution- one base pair is substituted for another  Inversion- a base pair is flipped

Original strand…A A T T C G C T T A A G C G 1.AATGTCGC 2. AATCGC TTACAGCG TTAGCG 3.ATTTCGC 4. ATATCGC TAAAGCG TATAGCG

Why are mutations good? EEnvironment is constantly changing. In order to survive, we must change. MMutations allow for variability (the basis of evolution)

Mutations Can Cause Genetic Disorders  Down’s Syndrome-3 copies of #21 chromosome (total 47 chromosomes)  Sterile Female-only one “X” chromosome (total of 45 chromosomes)  Sterile Male- XXY… (total of 47 chromosomes)

Why and How do they occur?  They can occur on their own  The chance of occurrence is increased by exposure to… X-rays Ultraviolet rays Radioactive substances Toxins (formaldehyde, asbestos, benzene, etc.)

Mighty Mystifying Mutations  Write a nice full paragraph that explains what mutations are and how they influence the code of life.  Use your notes and the following terms. *Mutation*Deletion*Variety *Body Cells*Sex Cells*Addition *Random*Inversion*Good *Bad*Substitution *Genetic Disorder

Evidence of Evolution…Part 2  The Theory of Evolution Evolution is change that occurs in the genes of living organisms over along period of time Evolution is used to explain differences among living things Differences can be in structures, functions, or behaviors Organisms have similarities between them. This shows that…  Organisms have evolved from simple to complex  Similarities suggest common ancestry

Supporting Evidence for Evolution  I. Fossils Remains of once living organisms Sedimentary rock forms layers, life’s gradual changes are seen through layers Top layers are the youngest fossils Bottom layers are the oldest fossils Scientists have compared the fossils of different layers and found similarities which suggest ‘links’ between the fossils

Questions: 1.Fossils are found in __________rock. 2.Why aren’t many soft tissues found as fossils? 3.Rock records can also give clues about ancient climates. How do we know that climates have changed?

II. Comparative Anatomy  Looking at relationships of body structures and functions between organisms.

Homologous Structures  Similar structure, different function  Example: Forelimbs of various mammals Human-carrying, grasping Bats-flying Whale-swimming

Homology Vs. Analogy

Analogous Structures  Same function, different structure  Example: Bird wings and butterfly wings (bones vs. no bones)

Questions… 1.What are vestigial structures? 2.What is the vestigial structure of the cave fish?

III. Embryology  Similar stages of development give clues to evolutionary relationships Could you guess what the four embryos will become based upon their appearance? Which look the most similar?

IV. Comparative Biochemistry  Studying similarities and differences in genetic makeup  Scientists compare DNA, proteins, & RNA  A chimp’s DNA only differs by 1.6% when compared to a human’s DNA

V. Biogeography TThe continents have moved from original places. SSimilar species can be found in separated continents that were once joined. EExamples: Monkeys in Africa and South America Leopards in Africa and Jaguars in S. America

PANGEA  What are the names of the southern and northern land masses?

VI. Behavioral Studies  Study behavior to give evolutionary clues Domestic dogs and wolves both pack Domestic cats and lions both pounce What behavior is common among big cats and marine mammals? What other common behaviors have you noticed of animals in Hawaii?