Chapter 15: Taxonomy

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Chapter 15 Taxonomy
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Taxonomy

• the science of classifying
• Common names can be confusing and names can vary
  by region.
• Common Names

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History of Taxonomy

• Aristotle - land, water, air categories
• Linneaus - devised the current system of
  classification, which uses the following schema

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Classification of Organisms

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• species

• King
• Phillip
• Crossed
• Over
• From
• Great
• spain

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Scientific Names (By Linnaeus)

• The scientific name is always italicized or
  underlined.
• Genus is capitalized. Species is not.
• Scientific names can be abbreviated by using the
  capital letter of the genus and a period
  Example. P. leo (lion)
• All organisms have a scientific name - which is
  genus species (binomial nomenclature)
• Examples
• Panthera leo lion Panthera tigris - tiger
• Homo sapiens - human
• Quercus rubrum - red oak Quercus phellus - willow
  oak
• Acer rubrum - red maple

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Recognition of Species

• Members of the same genus are closely related.
• Only members of the same species can interbreed
  (under natural conditions)
• Reproductive isolation (barriers)
• Some hybrids do occur under unnatural conditions
  Ligers are crosses between tigers and lions.
  Labradoodles are crosses between labs and poodles.

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The Six Kingdoms
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Modern Criteria for Classification

• Anatomy what it looks like
• Development how it develops
• Biochemistry protein chains
• DNA (RNA) DNA sequences

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Evolutionary History

• Biologists differ in how they classify organisms.
• Systematics includes taxonomy AND phylogeny
  (evolutionary history of organisms)
• Cladistics method used to construct a phylogeny
• Cladogram diagram showing relationships

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Evolutionary Considerations

• Convergent evolution organisms evolve similar
  features independently
• Analogous characters similar structure but not
  similar in origin
• Homologous characters similar structure and
  similar origin
• Derived traits unique characteristics

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Using Dichotomous Keys

• A dichotomous key is a written set of choices
  that leads to the name of an organism.
• Scientists use these to identify unknown
  organisms.
• Consider the following animals. They are all
  related, but each is a separate species. Use the
  dichotomous key below to determine the species of
  each

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• 1.Has green colored body ......go to 2
• Has purple colored body ..... go to 4
• 2. Has 4 legs .....go to 3
• Has 8 legs .......... Deerus octagis
• 3.Has a tail ........ Deerus pestis
• Does not have a tail ..... Deerus magnus
• 4.Has a pointy hump ...... Deerus humpis
• Does not have a pointy hump.....go to 5
• 5.Has ears .........Deerus purplinis 
• Does not have ears ......Deerus deafus

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Answers

• A. Deerus magnusB. Deerus pestisC. Deerus
  octagisD. Deerus purplinisE. Deerus deafusF.
  Deerus humpis

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Chapter 13 Evolution

• by natural selection

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The Theory of Evolution

• In science, theories are statements or models
  that have been tested and confirmed many times.
• In science, the term "Theory" does not express
  doubt.

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Some questions that can be answered by evolution.

• Why do so many different animals have the same
  structures, the arm bones in a human are the same
  bones as a flipper in a whale?
• Why do organisms have structures they no longer
  use, like the appendix in a human? Non
  functioning wings in penguins
• Why are there bones and fossil evidence of
  creatures that no longer exist? What happened to
  these creatures?
• Why do so many organisms' morphology and anatomy
  follow the same plan?
• Why is the sequence of DNA very similar in some
  groups of organisms but not in others?
• Why do the embryos of animals look very similar
  at an early stage?

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• The Theory of Evolution is considered a Unifying
  Theory of Biology, because it answers many of
  these questions and offers an explanation for the
  data.

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Lamarck's Theory of Acquired Characteristics

• Some thought that you would gain or lose features
  if you overused or didn't use them, and you could
  pass these new traits onto your offspring.

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• This was known as the Inheritance of Acquired
  Characteristics
• A lizard that didn't use it legs would eventually
  not have legs and its offspring wouldn't have
  legs
• A giraffe stretched its neck to reach higher
  leaves, and this stretched neck would be a trait
  inherited by its offspring

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• Lamarcks Theory was eventually discarded -
  PROVEN TO BE WRONG!
• Why? Logically it doesn't work. Imagine if you
  were in a car accident and had a leg amputated.
  This does not mean that your children will only
  have one leg. Features gained during life are not
  passed on to children.

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Darwin's Theory of Evolution by Natural Selection

• Darwin was a naturalist who observed many
  species.
• He is famous for his trips to the Galápagos
  Islands(HMS Beagle voyage), his observations of
  the finches (and other animals), and

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• the book he wrote "The Origin of Species
• 1. Variation exists among individuals in a
  species.
• 2. Individuals of species will compete for
  resources (food and space)
• 3. Some competition would lead to the death of
  some individuals while others would survive
• 4. Individuals that had advantageous variations
  are more likely to survive and reproduce.

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• This process he describes came to be known as
  Natural Selection
• The favorable variations are called Adaptations

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Darwin's Finches
Darwin noted that all the finches on the
Galápagos Island looked about the same except for
the shape of their beak. His observations lead to
the conclusion that all the finches were
descendents of the same original population. The
shape of the beaks were adaptations for eating a
particular type of food (Ex. long beaks were used
for eating insects, short for seeds)
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Evidence of Evolution

• 1. Fossil Evidence
• If today's species came from ancient species, the
  we should be able to find remains of those
  species that no longer exist.
• We have tons of fossils of creatures that no
  longer exist but bear striking resemblance to
  creatures that do exist today.
• Carbon dating--gives an age of a sample based on
  the amount of radioactive carbon is in a sample.
• Fossil record---creates a geologic time scale.

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• 2. Evidence from Living Organisms
• Evidence of Common Ancestry --Hawaiian
  Honeycreeper
• Homologous Structures--structures that are
  embryologically similar, but have different
  functions, the wing of a bird and the forearm of
  a human
• Vestigial Organs--seemingly functionless parts,
  snakes have tiny pelvic and limb bones, humans
  have a tail bone
• Biochemistry and DNA
• Embryological development--Embryos of different
  species develop almost identically
• Observation of species change (wolves/dogs,
  peppered moths)

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Change over time?

• Gradualism vs. Punctuated Equilibrium

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Examples of Evolution

• 1. industrial melanism (Kettlewell's moths)
• 2. dog breeds
• 3. viruses vaccines
• 4. bacteria antibiotics
• 5. elephant tusks

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Species Formation

• 1. Original Species
• 2. Ecological races reproduction isolation
• Geographically, physically, differing mating
  periods, no attraction, hybrids (infertile), etc.
• 3. New Species

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Human Pig
Chicken Fish
Next
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Chapter 16

• Populations

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Population

• All the individuals of a species that live
  together in an area.
• Demography the statistical study of populations,
  make predictions about how a population will
  change.

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Three Key Features of Populations

• Size
• Density
• Dispersion (clumped, even, random)

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Growth Rate

• Birth Rate - Death Rate
• 1. In Cedar Grove, 15 babies were born in 2000, 4
  residents died. What is the growth rate for Cedar
  Grove?
• 2. In Springfield, 70 babies were born in 2000,
  80 residents died. What is the growth rate?

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Growth Curves

• J - Shaped (exponential growth)
• S - Shaped (logistic model)
• Populations are limited by space, food. That
  limit is called the CARRYING CAPACITY

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Human Population
Exponential Growth!
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• The graph shows a logistic population curve.
• At what level do the deer reach their CARRYING
  CAPACITY?

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What Limits Population Size?

• Density-dependent factors limited resources-
  space, food, water, air
• Density-independent factors random occurrences
  that can limit population - earthquake, bad
  weather
• Is disease density dependent, or density
  independent?

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Growth Strategies

• R Strategists
• short life span
• reproduce quickly
• have many young
• little parental care
• Ex cockroaches, weeds, sea turtles

• K Strategists
• long life span
• reproduce slowly
• have few young
• parental care
• Ex humans, elephants

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Population Pyramids

• Population of a Growing Country

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• Population of a Stable Country

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Ways To Estimate Populations

• 1. Random Sample
• 2. Mark Recapture

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How Populations Evolve

• 1. Populations change over time as a result of
  environmental pressure (evolution)
• 2. Allele frequencies in population change if
  evolutionary forces act upon them (Hardy Weinberg
  Principle)
• 3. Mutation is the source of variation

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• Gene Flow the movement of individuals to and
  from a population, migration
• Non random mating individuals mate with other
  individuals of their choosing, choice depends on
  individual and species
• Genetic Drift occurs in isolated populations,
  they become more alike (cheetahs)

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Natural Selection Causes Changes in Population

• Directional Selection evolution favors an
  extreme trait, more and more individuals have the
  trait. Rats get longer and longer tails
• Stabilizing selection extremes are selected
  against, favors the average

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Back
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Ti-tigon and tigon
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References

• Jellyfish Pic www.aloha.com/lifeguards/jelyfish
  .html
• Linneaus Pic www.gerbera.org/carl-von-linne.html
  
• Aristotle Pic http//dbhs.wvusd.k12.ca.us/webdoc
  s/Gallery/Gallery1.html
• Liger Pics http//www.mosnews.com/news/2004/12/0
  6/liger.shtml, http//www.tigers-animal-actors.com
  /index2.html, http//www.shambala.org/biographies/
  patrick.htm
• Natural Selection, Finch, Taxonomy Pic
  faculty.capebretonu.ca/callison/BIO101Figures.htm
• Mustard N.S. Pic http//fig.cox.miami.edu/cmall
  ery/150/animal/mustards.jpg
• Moth Pic www.tiscali.co.uk/.../hutchinson/m00080
  72.html
• Punctuated vs. Gradualism Pic
  http//www.zo.utexas.edu/faculty/sjasper/images/24
  .17.gif
• Cladogram Pic http//www.anselm.edu/homepage/jpi
  tocch/genbios/25-11-Cladogram-L.jpg
• Dispersion Patterns http//www.bio.miami.edu/dan
  a/pix/dispersion.jpg