Unit II: Biodiversity

1
Unit II Biodiversity

• Classifying Living Things

2
Introduction

• Millions of living things are known today, with
  more constantly being identified.  The opinions
  of scientists range anywhere from the possibility
  of ten to thirty million as being the total
  number of species actually in existence. 
• In order to make sense of this vast number of
  species requires a taxonomic organizational
  structure that allows scientists and students to
  investigate the types and characteristics of
  these living things

3
This unit will introduce the

• Historical development of our present day
  taxonomic system.
• Characteristics of living things
• Present day taxonomic methods
• Classification of viruses
• Classification of Plants
• Classification of invertebrates
• Classification of vertebrates

4
Characteristics of Living Things

• Biologists differentiate living things from
  non-living things on the basis of various
  characteristics. These may include, behavior,
  needs, uses of matter and energy, physical
  features, etc. Specific characteristics include
• Organized systems made up of one or more cells.
• In multicellular organelles these cells are often
  organized further into tissue, organs, and
  systems.
• Metabolize matter and energy.
• Matter and energy is needed to carry out the
  chemical reactions that all living things need to
  do to survive.
• Interact with their environment and are
  homeostatic.
• Through their activities of obtaining nutrients
  they maintain homeostasis.

5
Characteristics of Living Things

• Grow and develop.
• Unicellular organisms grow until it is time for
  them to divide. Depending on the species this
  could take hours to a few days.
• Multicellular organisms grow and mature. As they
  mature sex cells develop which enable them to
  reproduce.
• Reproduce (biogenesis).
• Living things produce living things. It is
  through the genetic material that the information
  required for life is passed on to the next
  generation.
• Adapt to their surroundings.
• Through evolution living things have evolved
  structures that allow them to exist in varying
  conditions, eg. Elephants, polar bears, etc.

6
Why There is a Need for Classifying

• To date scientists have classified approximately
  1.5 million organisms.
• A conservative estimate is that there is over 20
  million species left to be discovered!

7
How Scientists Classify Organisms

• Biologists place the organisms into groups based
  on their characteristics.
• By classifying, biologists can organize living
  things into groups.
• This branch of biology is referred to as taxonomy
  

8
Taxonomy Definition

• The branch of Biology that deals with the naming
  and placing of all organisms into groups.

9
Early Classification Schemes

• Aristotle was the first to use a system of
  classification for organisms.
• He placed all organisms into one of two groups.
• He classified animals according to where in the
  environment they lived and structural
  similarities.

10
(No Transcript)
11
(No Transcript)
12
Classification by Theophrastus

• Theophratus was a student of Aristotle and he
  furthered his mentor's work by classifying
  plants.
• He classified them according to their stem
  structure

13
(No Transcript)
14
(No Transcript)
15
The Third Kingdom - Protista

• The invention of the microscope and the discovery
  of microscopic organisms required further
  classification
• These organisms were considered neither plants
  nor animals
• In 1866 Ernst Haeckel added a third Kingdom, he
  placed single celled organisms in a kingdom he
  called Protista

16
The Fourth Kingdom - Fungi

• As knowledge about different organisms grew
  additional kingdoms were added
• Mushrooms and mold were first placed in the plant
  kingdom
• It was discovered that they do not carry out
  photosynthesis and were placed in their own
  kingdom called Fungi

17
The Fifth Kingdom - Bacteria

• The Kingdom Protista required further subdivision
  because bacteria have a different cell structure
  than other protists.
• Bacteria were placed in their own kingdom called
  Bacteria
• This kingdom is also referred to as Eubacteria,
  Prokaryotae, or Monera.

18
The Sixth and Final Kingdom - Archaea

• Research into bacteria that live in very severe
  conditions, such as hot or acetic springs, or
  salt lakes have shown that these organisms have
  developed unique structures and mechanisms that
  allow them to survive there.
• They have reclassified these organism and placed
  them into their own kingdom called Archaea

19
Biological Domains and Kingdoms

• As a result Biologists have created a new level
  of classification above kingdom.
• This new level is called Domain and is based upon
  the type of cells present
• There are 3 Domains with 6 Kingdoms distributed
  through them

20
(No Transcript)
21
(No Transcript)
22
Linnaeus

• As modern science developed in the fifteenth and
  sixteenth centuries, Aristotle's system was
  INADEQUATE.
• They also found that Using COMMON NAMES, such as
  robin or fir tree, for an organism presented its
  own problems  common names varied from on locale
  to the next and common Names May Not describe
  species accurately.
• Carl VON Linne, (Carols Linnaeus) mid-1700s,
  Swedish Biologist established a simple system for
  classifying and naming organisms. He developed a
  Hierarchy (a ranking system) for classifying
  organisms that is the Basis for Modern Taxonomy.

23
Linnaeus II

• Linnaeus used an organisms MORPHOLOGY, that is
  its Form and Structure, to categorize it.  His
  system is still being used today.
• Linnaeus established a system of groups called
  TAXA. (TAXON)
• EACH TAXON IS A CATEGORY INTO WHICH RELATED
  ORGANISMS ARE PLACED.
• Linnaeus used Latin for the Names of the Taxa,
  because this was the language of educated people
  and not an everyday language likely to change.
• Linnaeus is the Father of Modern Taxonomy.

24
Linnaeus III

• Linnaeus based his system upon STRUCTURAL
  SIMILARITIES BETWEEN ORGANISMS.
• THE SYSTEM OF CLASSIFICATION LINNAEUS DEVELOPED
  IS A HIERARCHY, OR RANKING SYSTEM.
• In his system of classification, he ranked the
  categories from the Broadest and Most General
  TAXA (THE TWO KINGDOMS - PLANTS AND ANIMALS) to
  the Smallest and Most Specific TAXA (INDIVIDUAL
  SPECIES).

25
Linnaeus IV

• He first divided all organisms into TWO GROUPS,
  PLANTS AND ANIMALS. THAT WERE CALLED KINGDOM
  PLANTAE AND ANIMALIA.
• HE THEN BROKE DOWN EACH GROUP AS FOLLOWS
•    A.  EACH KINGDOM INTO SMALLER GROUPS CALLED
  Phylum.
• B. EACH phylum INTO SMALLER GROUPS CALLED
  CLASSES
•  C.  EACH CLASS WAS DIVIDED INTO ORDERS.
•  D.  EACH ORDER WAS DIVIDED INTO GENERA (GENUS)
•  E.  AND GENERA WERE DIVIDED INTO SPECIES.
• EACH LEVEL GROUPS TOGETHER ORGANISMS THAT SHARE
  MORE CHARACTERISTICS WITH EACH OTHER.

26
Kingdom Bacteria

• Also called Kingdom Eubacteria, Prokaryotae, or
  Monera
• Unicellular organisms
• Prokaryotic - do not have a nuclear membrane and
  lack many organelles.
• They may be photosynthetic, chemosynthetic, or
  feed by absorption.

27
Characteristics of Kingdom Bacteria

• Chemosynthesis is the production of sugars with
  energy supplied by the breakdown of other
  elements.
• Chemosynthesis of carbohydrates occurs in the
  nitrite bacteria through the oxidation of ammonia
  to nitrous acid, and in the nitrate bacteria
  through the conversion of nitrous into nitric
  acid.

28
(No Transcript)
29
Kingdom Archaea

• Also called Archaebacteria
• These bacteria-like organisms posses a differing
  cell wall composition that allows them to survive
  extreme conditions such as salt lakes, or hot
  acidic springs

30
(No Transcript)
31
Domain Eukarya

• This domain includes all living organisms that
  are composed of one or more Eukaryotic cells
• It includes the Kingdoms Protista, Fungi,
  Plantae, and Animalia

32
Kingdom Protista

• Most are unicellular
• Eukaryotic
• May be photosynthetic, may feed by absorption, or
  may ingest food.

33
(No Transcript)
34
Kingdom Fungi

• Most multicellular although some are unicellular.
  
• Eukaryotic cell structure
• Absorptive Heterotrophs
• Non Motile

35
(No Transcript)
36
Kingdom Plantae

• Multicellular
• Eukaryotic
• Photosynthetic
• Non Motile

37
(No Transcript)
38
Kingdom Animalia

• Multicellular
• Eukaryotic
• Ingestive Heterotrophs
• Motile
• Nervous system present

39
Invertebrates
40
Classification Categories

• Domain
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

41
Humans are classified in the following way

• Kingdom Animalia
• Phylum Chordata
• Class Mammalia
• Order Primates
• Family Hominidae
• Genus Homo
• Species Sapien

42
The domestic dog is classified in the following
way.

• Kingdom Animalia
• Phylum Chordata
• Class Mammalia
• Order Carnivora
• Family Canidae
• Genus Canis
• Species familaris

43
Naming Organisms

• In addition to classifying organisms, taxonomists
  also name each type of living organism.
• Naming is also called Nomenclature

44
Binomial Nomenclature

• Means - "Two names"
• Taxonomists name organisms by stating the
  organisms genus followed by a given species name.
  
• The genus name is capitalized because there may
  be many species within that genus.
• The species name is unique to that individual
  type of organism.
•  Homo sapiens - Humans
• Canis familaris - dog
• Canis lupus - wolf
• Canis latrans - coyote

45
The Use of Latin in Naming

• Latin is used for naming.
• Latin at one time was the language of scholars.
• Today it is used because it avoids having to
  translate scientific names into the various
  different languages where different words have
  different meanings.

46
Common Names

• In addition to scientific names organisms are
  also given common names that are used every day
  by non-scientific people.
• Common Names Can Cause Confusion!
• Starfish - not a fish
• Capsicum frutescens what we may know as the
  green pepper is also referred to as a bell
  pepper, sweet pepper or mango depending on the
  place.
• Common names also vary from language to language

47
Benefit of Universal Naming

• A universal system of naming allows us to avoid
  the confusion associated with common names, and
  tells us something about evolutionary
  relationships.

48
Dichotomous keys

• A dichotomous key is an identification key that
  uses a series of paired comparisons to sort
  organisms into smaller and smaller groups.
• used as a way to classify organisms
• available for almost all living things
• used by all types of scientists
• consists of many numbered steps
• first few steps key on gross external features
• moves from general to specific
• each step contains two or more statements of
  which only one is true about a single organism
• the true step directs the user to the next step
  or to the organism

49

• A key is a listing of specific characteristics,
  divided into two equal parts.
• A dichotomous key is a series of two choices or
  opposing statements, known as a couplet.
• Some specific characteristics for identification
  of organisms could be structure and function.

50
Phylogeny

• Many new organisms and some sub - groups have
  been added. Most large plants and animals have
  common names, which can lead to confusion. Modern
  techniques consider the evolutionary history of a
  species (called phylogeny).
• A phylogenetic tree is used to show the
  relationships among various organisms. (See
  Figure 4-14, p. 116) The phylogenetic tree
  represents a hypothesis about the evolutionary
  relationships among a group of phylogeny).
• A phylogenetic tree is used to show the
  relationships among various organisms.

51
Cladistics

• Cladistics refers to a classification scheme
  that is based on phylogeny.
• It is based on the idea that each group of
  related species had one common ancestor, and
  organisms retain some ancestral characteristics
  and gain some unique derived characteristics as
  they evolve and diverge from the common ancestor.
  ( p.117)

52
(No Transcript)
53
Modern techniques used to help classify organisms
How organisms are classified

• There are six methods of classification

54
1. Evidence from fossil records

• Radioactive dating uses the decay of carbon-14 to
  find the ages of some organisms. They can then
  tell if they were ancestors of some species.

55
2. Evidence from anatomy

• Structural information is the comparison of bones
  found in certain animals.
• For example, the human arm , horses leg , bats
  wing , whale flipper are all quite similar.
• They have similar arrangement and the
  similarities of bone structure indicate the same
  evolutionary origin.

56
(No Transcript)
57
3. Evidence from embryonic development

• Comparative embryology is the comparisons of
  early embryonic development.
• For example, tunicates, in their larval stage,
  have structures that are similar to tadpoles such
  as long dorsal nerve cords and a flexible
  notochord. They are therefore classified with
  other vertebrates.

58
4. Evidence from biochemistry (Protein)

• Biochemical techniques can look at the
  arrangement of amino acids.
• For example, human blood and baboon blood are
  very close therefore humans are more closely
  related to baboons than horses. Similar DNA
  patterns would suggest that the relationship
  between organisms is closer.
• Protein comparisons of amino acid sequences are
  checked for similarities and differences. The
  blood proteins in horseshoe crab reveal that it
  is more closely related to spiders than crabs.

59
5. Evidence from DNA

• DNA analysis is a good way measuring the
  closeness of relationships among organisms.

60
6. Metabolic Behaviour

• Events such as the ability to digest certain
  substances or if an organism is a producer, a
  consumer, or a decomposer can also be used in
  classifying organisms.

61
Summary of how organisms are classified
62
What Are Viruses?

• Viruses are tiny (20 - 400 nm) particles composed
  of a nucleic acid core (either DNA or RNA)
  surrounded by a protein coat (capsid) and
  sometimes a membrane envelope (derived from its
  host cell)
• Viruses are incapable of reproduction independent
  of host cells whose cellular machinery is taken
  over by the virus and used as a factory for
  producing new viruses

63
What Are Viruses?

• Viruses are tiny (20 - 400 nm) particles composed
  of a nucleic acid core (either DNA or RNA)
  surrounded by a protein coat (capsid) and
  sometimes a membrane envelope (derived from its
  host cell)
• Viruses are incapable of reproduction independent
  of host cells whose cellular machinery is taken
  over by the virus and used as a factory for
  producing new viruses

64
Example of Viral Reproduction T4 virus Lytic
Cycle (steps in viral replication)(See Figure
4.21, p. 123).

• 1) Attachment The T4 phage is a complex virus
  that attaches to a specific receptor site on a
  hosts (such as E. coli) cell wall. Weak chemical
  bonds form between the attachment and receptor
  sites, adhering the virus to the host.
• 2) Entry (Penetration) T4 injects its nucleic
  acid (DNA) into the host (E. coli). The viral DNA
  passes through the core and into the cell. The
  capsid remains outside.

65

• 3) Replication Host protein synthesis is stopped
  by viral degradation of host DNA. The hosts
  metabolism will replicate the viral DNA (or RNA).
• 4) Assembly Spontaneous assembly of new virus
  particles occurs.
• 5) Lysis and Release The host cell, (ie.) E.
  colis plasma membrane and cell wall, lyses (or
  breaks open), releasing the new virus particles.
  The host (E. coli) cell dies.
• See Figure 4.21

66
Are Viruses Alive?

• Viruses require cells to reproduce and do not
  have cells of their own, thus they do not fit the
  Cell Theory which states that being made out of
  cells is a characteristic of living things
• Are viruses missing links between living and
  non-living things?
• No, viruses require cells to reproduce, so cells
  had to come first then viruses thus viruses
  cannot serve as a missing link between living
  and non-living things