Life Structure and Function BA Review

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Life Structure and Function BA Review

• February 8th, 2005
• Dickinson, Eliuk and Naszradi 7th grade class

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Scientific Method

• 7 steps
• Allow scientists to complete experiments that are
  reproducible and accurate

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Scientific Method
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Scientific Method

• 1) Choose a problem
• State the problem as a question
• Ex. You want to build a strong, cheap bridge
• 2) Gather information
• Read, get advice, make observations
• Ex. You look up what kinds of bridges there are
  and what looks strong
• 3) Form a hypothesis
• Make a prediction about what will happen
• Ex. You decided what kind of bridge you would
  make, thinking it would be the strongest and
  cheapest

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Scientific Method

• 4) Design an experiment
• Figure out how you will test your hypothesis
• Ex. Use weight to test structural strength
• 5) Perform an experiment
• This is how you will test your hypothesis
• Ex. We put weights on your bridge until it broke,
  then looked at how much you spent

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Scientific Method

• 6) Analyze data
• Put data into tables, graphs and other organized
  forms so you can look at it and see what it means
• Ex. You put your account book in a table, looked
  at the weight it held and determined how you did
  against other groups
• 7) Draw conclusions
• Summarize what youve found and what you think it
  means
• Ex. You decided how good or poorly your bridge
  did and figured out how you would do it better.

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Scientific Method

• Hypothesis supported Repeat the experiment to
  make sure your results are accurate
• Hypothesis not supported Revise your
  hypothesis, follow the steps of the scientific
  method again.

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Living Things

• All living things have 5 common traits
• Louis Pasteur biogenesis, or living things come
  from other living things
• 1) Living things are organized
• Cells
• Can have many cells or just one cell
• Ex. Digestive system, skin, heart

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Living Things

• 2) Living things respond
• Interact with the surroundings
• Ex. Cat runs for kitchen when it hears the can
  opener
• 3) Living things use energy
• Energy is used to carry out functions and allows
  the organism to live
• Ex. Humans eat food at lunch to give them energy
  for the afternoon

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Living Things

• 4) Living things grow and develop
• Change as they get older
• Ex. Dogs start off as puppies and as they get
  older get larger
• 5) Living things reproduce
• Have offspring that carry on the species
• Ex. Humans have babies

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Cells

• There are 2 kinds of cells
• Plant and animal
• Help organize jobs in living organisms
• Have a nucleus and organelles (mitochondria,
  chloroplast, endoplasmic reticulum, etc)

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Animal Cell
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Plant Cell
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Tissues and organs

• Tissue group of similar cells that work
  together to do one job
• Ex. Skin, muscle
• Organ two or more different tissues working
  together
• Liver, kidney, nervous system

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DNA

• Deoxyribonucleic acid
• Contains information for an organisms growth and
  function

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DNA
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Genetics

• Genetics the study of how traits are inherited
  through the interactions of alleles
• Father of genetics is Gregor Mendel
• Studied pea plants

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Genetics Terminology

• Allele different forms of a trait an organism
  may have
• Dominant allele covers up (dominates) the other
  alleles
• Recessive allele hidden by the dominant allele
• Genotype letters of the code

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Genetics Terminology

• Phenotype the way an organism looks
• Homozygous two alleles are the same
• Heterozygous two alleles are different
• Punnett square tool to predict Mendelian
  genetics

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Punnett Squares

• We cross two heterozygous red rose bushes (Rr)

R
r
RR
Rr
R
Rr
rr
r
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Punnett Square

• Dominant allele R
• Recessive allele r
• Genotype RR, Rr, rr
• Phenotype Red, white
• Ratio of Red to White 31

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Heredity

• Heredity the passing of traits from parent to
  offspring
• Inherited trait directly from your parents, no
  choice in the matter
• Ex. Hair color, eye color, cheek dimples
• Acquired trait personal preference, you have a
  choice
• Ex. Favorite food, favorite music, etc

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Darwin

• English scientist
• Explained how organisms evolve through natural
  selection
• Made the 5 principles of natural selection

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Natural Selection

• 1) Organisms produce more offspring than can
  survive
• Ex. Hundreds of sea turtle eggs, only 25-50 will
  survive to adulthood
• 2) Differences, or variations, occur among
  individuals
• Ex. All small beaked finches and 1 large beaked
  finch

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Natural Selection

• 3) Variations are passed to offspring
• Variation inherited trait that makes an
  individual different from other members of its
  species
• Ex. Large beaked finches pass this trait to their
  offspring
• 4) Some variations are helpful. Only those that
  are will survive
• Ex. If large beak does not help finch survive it
  will not live
• If an organism moves to another population it
  takes its favorable DNA with it, helping to bring
  about evolution

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Natural Selection

• 5) Over time, the offspring of individuals with
  favorable traits will make up more of a
  population, thus becoming a separate species
• Ex. Large beaked finches eventually became a
  separate species from the small beaked finches

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Natural Selection

• AKA survival of the fittest
• Those with the best traits, that allow it to
  survive, will survive. If the traits harm it
  then the organism will not continue to surive.

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Homologous Structures

• Homologous structure body parts that are
  similar in origin and structure that may or may
  not have the same function
• Show that two or more species have a common
  ancestor
• To test this scientists can compare DNA samples

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Homologous Structures
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Flow Charts

• Similar to dichotomous keys
• Follow the paths to determine what the organism
  is at the end

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Flow Charts
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Fossils

• Fossils are found in sedimentary rock
• Oldest fossils always found in deepest rock layer

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Fossils
A
B
C