Chapter 18 Classification - PowerPoint PPT Presentation

View by Category
About This Presentation
Title:

Chapter 18 Classification

Description:

Chapter 18 Classification Why Classify?? Human nature- we love to put things in their place! Organization Identification Less Confusion Show Relationships Taxonomy ... – PowerPoint PPT presentation

Number of Views:154
Avg rating:3.0/5.0
Slides: 71
Provided by: Bren2172
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Chapter 18 Classification


1
Chapter 18 Classification
2
Why Classify??
  • Human nature- we love to put things in their
    place!
  • Organization
  • Identification
  • Less Confusion
  • Show Relationships

3
Taxonomy
  • The branch of biology that names and groups
    organisms according to their characteristics and
    evolutionary history.
  • Classify the thousands of new species discovered
    each year.
  • 1. 5 million so far
  • ?? millions yet to be discovered.

4
  • Biologists use the characteristics of newly
    discovered species to classify it with organisms
    having similar characteristics.
  • The way we group organisms today continues to
    change and reflect the evolutionary history of
    organisms.

5
Early Systems of Classification
  • Aristotle
  • Linnaeus

6
Aristotle
  • Greek Philosopher 384-322 BC
  • First classified organisms more than 2000yrs ago
    as either plants or animals.
  • Animals land dwellers, water dwellers, or air
    dwellers.
  • Plants three categories based on differences in
    their stems.

7
Aristotle
8
Carolus Linnaeus
  • Father of Taxonomy
  • Swedish naturalist
  • 1707-1778
  • 100 years before Darwin!

9
  • 1735 published Systema Naturae.
  • Devised a system of grouping organisms into
    hierarchical categories.
  • Used an organisms morphology (form and
    structure) its appearance

10
1707-1778
11
Levels of Classification
  • Kingdom
  • Phylum or Division
  • Class
  • Order
  • Family
  • Genus
  • Species

12
King Philip Came Over For Gold Specks
13
  • Under the modern Linnaean system, the
    classification of an organism places the organism
    within a nested hierarchy of taxa. (taxon
    singular)

14
(No Transcript)
15
(No Transcript)
16
Binomial Nomenclature
  • Scientific Name has two parts.
  • 1st part is the genus
  • 2nd part is the species which is the identifier
    or descriptive word.
  • Genus name is capitalized and both names are
    underlined or written in italics.

17
  • Latin used by all scientists as a standard.
  • Linnaeus classified 1000s of organisms.
  • Versions of his system are still used today.

18
Scientific Names
  • May describe the organism, suggest geographic
    range, or honor a person
  • Homo sapiens (homo man sapiens wise)
  • Chaos chaos (amoeba never appear the same shape)

19
Linnaea borealis (Linnaeus favorite, borealis
northern)
20
  • Lupinus texensis
  • Texas bluebonnet

21
Phylogeny
  • Phylogeny is evolutionary history
  • Much of Linnaeus work in classification is
    relevant even in the context of phylogeny because
    morphological features are largely influenced by
    genes and are clues of common ancestry.

22
Evolutionary Classification
  • Biologists now group organisms into categories
    that represent lines of evolutionary descent, or
    phylogeny, not just physical similarities
  • Phylogeny the study of evolutionary
    relationships

23
(No Transcript)
24
Modern taxonomic placement involves
  • Morphology
  • Chromosomal characteristics
  • Nucleotide and amino acid sequences (chromosomes)
  • Embryological development
  • Information from the fossil record.

25
Phylogenetic tree
  • Family tree that shows the evolutionary
    relationships thought to exist among groups of
    organisms.
  • Represents a hypothesis and is based on several
    lines of evidence.
  • Subject to change as new information arises.

26
Phylogenetic Tree
27
Interpreting a Phylogenetic Tree
  • Organism at base of tree is common ancestor to
    all the others in the tree.
  • Branch points indicate the evolution of some
    characteristic that splits a group into two
    groups.
  • Groups shown at tips of branches include
    organisms that have evolved most recently.

28
Molecular Clocks
  • This model uses comparisons of DNA, RNA and
    proteins to estimate the length of time that two
    species have been evolving independently.
  • The degree of dissimilarity is, in turn and
    indication of how long ago the two species shared
    a common ancestor.

29
DNA comparisons (Artic bluegrass)
30
DNA banding patterns
31
(No Transcript)
32
Cladistics
  • Relatively new system of phylogenetic
    classification.
  • Uses certain features of organisms called shared
    derived characteristics to establish evolutionary
    relationships.

33
  • Derived character feature that apparently
    evolved only within the group under
    consideration. Example feathers in birds are
    inherited from a common ancestor.

34
To interpret a cladogram
  • Begin at the bottom and move up the axis that
    shows branch points.
  • Groups and derived characteristics appeared in
    the order shown.
  • Example all groups branching above lungs have
    lungs. Those below do not.

35
Cladogram
36
Two Modern Systems of Classification
  • Six Kingdom System
  • Three Domain System

37
Six Kingdom System
  • Kingdom Archaebacteria
  • Kingdom Eubacteria
  • Kingdom Protists
  • Kingdom Fungi
  • Kingdom Plantae
  • Kingdom Animalia

38
Six Kingdoms
39
Kingdom Archaebacteria
40
Kingdom Archeabacteria
  • Prokaryotic
  • Unicellular
  • Cell walls (without peptidoglycan)
  • Autotroph or heterotroph

41
Kingdom Archaebacteria
  • Some autotrophic produce food by chemosynthesis
    and methane waste.
  • archae ancient
  • May be directly descended from and very similar
    to first organisms on Earth

42
  • Can withstand extreme conditions
  • Thermophiles (heat)
  • Halophiles (salt)
  • Methanogens (methane gas)
  • Many live in harsh environments sulfurous hot
    springs, salty lakes, anaerobic environments,
    intestines of animals.

43
Kingdom Eubacteria
44
Kingdom Eubacteria
  • eu true
  • Prokaryotic
  • Unicellular
  • Cell walls (with peptidoglycan)
  • Autotroph or heterotroph

45
  • Bacteria that affect your life tooth decay, turn
    milk to yogurt, food poisoning, illness
  • Most use oxygen, but a few cannot live in O2
  • Both Eubacteria and archaebacteria make up the
    greatest number of living things on Earth.

46
  • Eubacteria and archaebacteria reproduce by binary
    fission but do have methods of genetic
    recombination to allow evolution to occur.
  • Short generation times (30 minutes) allow rapid
    evolutionary response to environmental change.
    Example antibiotic resistant bacterial infection.

47
Kingdom Protista
48
Kingdom Protista
  • Eukaryotic
  • Cell walls of cellulose
  • Mostly single-celled organisms, but some
    multicellular but lack specialized tissues
  • Autotrophic and heterotrophic
  • Include Protozoa and Algae

49
(No Transcript)
50
(No Transcript)
51
  • Many species distantly related.
  • Broad kingdom contains all eukaryotes that are
    not plants, animals, or fungi. 50,000 species.
  • Sexual cycles of many are unknown but thought to
    have some process of genetic recombination.

52
Kingdom Fungi
53
Kingdom Fungi
  • Unicellular and multicellular
  • Eukaryotic
  • Cell walls of chitin
  • Heterotrophic
  • Absorb nutrients rather than ingesting
  • 100,000 species mushrooms, yeast, mildews, and
    molds.

54
  • Sexual cycles not known for many fungi. It is
    likely that all species have some way of
    promoting genetic recombination.

55
Kingdom Plantae
56
Kingdom Plantae
  • Multicellular plants
  • All except for a few parasitic forms are
    autotrophic and use photosynthesis as a source of
    energy
  • Eukaryotic
  • Most live on land
  • Sessile dont move around

57
  • Most have a sexual cycle based on meiosis
  • 350,000 species identified including mosses,
    ferns, conifers, flowering plants.

58
Kingdom Animalia
59
Kingdom Animalia
  • Eukaryotic Heterotrophs
  • Multicellular No cell walls
  • Most have symmetrical body organization
  • Move about their environment
  • Have a sexual cycle based on meiosis
  • About 1,000,000 species

60
(No Transcript)
61
Three Domain System
  • Molecular biology has led to an alternative to
    the 6 kingdom system
  • Comparing sequences of ribosomal RNA in many
    organisms. Estimated how long ago pairs of
    organisms shared a common ancestor.

62
  • Phylogenetic tree drawn from this data shows that
    living things seem to fall naturally into 3 broad
    groups or domains.

63
(No Transcript)
64
(No Transcript)
65
The Three Domains (and the kingdoms they include)
  • Bacteria (Eubacteria)
  • Archaea (Archaebacteria)
  • Eukarya (Eukaryotes) includes Protista, Fungi,
    Plantae, Animalia

66
(No Transcript)
67
Three Domains
68
Three Domains
69
Conclusions from the Three Domain System
  • All eukaryotes have true nuclei with linear
    chromosomes and membrane-bound organelles.
  • The most variation in Eukarya is among protists.

70
  • When considered from the perspective of the
    complete diversity of life on Earth, the fungi,
    plants, and animals are quite similar to each
    other.
About PowerShow.com