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Classification. Chapter 18. Characteristics of Living Things. Section 1-3. Characteristic. Examples. Living things are made up of units called cells. Many microorganisms consist of only a single cell. Animals and trees are multicellular. Living things reproduce.

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classification

Classification

Chapter 18

slide2

Characteristics of Living Things

Section 1-3

Characteristic

Examples

Living things are made up of units called cells.

Many microorganisms consist of only a single cell. Animals and trees are multicellular.

Living things reproduce.

Maple trees reproduce sexually. A hydra can reproduce asexually by budding.

Living things are based on a universal genetic code.

DNA: Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees.

Living things grow and develop.

Flies begin life as eggs, then become maggots, and then become adult flies.

Living things obtain and use materials and energy.

Metabolism: Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat.

Stimulus: Leaves and stems of plants grow toward light.

Living things respond to their environment.

Homeostasis: Despite changes in the temperature of the environment, a robin maintains a constant body temperature.

Living things maintain a stable internal environment.

Taken as a group, living things change over time.

Evolution:Plants that live in the desert survive because they have become adapted to the conditions of the desert.

slide3

Figure 1-21 Levels of Organization

Section 1-3

Biosphere

The part of Earth

that contains all

ecosystems

Biosphere

Ecosystem

Community and

its nonliving

surroundings

Hawk, snake, bison, prairie dog, grass, stream, rocks, air

Community

Populations that

live together in a

defined area

Hawk, snake, bison, prairie dog, grass

Population

Group of

organisms of one

type that live in

the same area

Bison herd

slide4

Figure 1-21 Levels of Organization continued

Section 1-3

Organism

Individual living

thing

Bison

Tissues, organs,

and organ systems

Groups of

Cells

Nervous system

Brain

Nervous tissue

Smallest functional

unit of life

Cells

Nerve cell

Groups of atoms;

smallest unit of

most chemical

compounds

Molecules

DNA

Water

why do we classify organisms
Why Do We Classify Organisms?
  • Biologists group organisms to represent similarities and proposed relationships.
  • Classification systems change with expanding knowledge about new and well-known organisms.

Tacitus bellus

taxonomy system of classification
Taxonomy--system of classification
  • Name organisms
  • Group organisms in a logical manner
  • Establishes common set of criterion regardless of language or country
classification and phylogeny
Classification and Phylogeny
  • Common names are problematic
    • vary among languages and even among regions within a country
    • Early naming attempts were up to 20 words
  • Binomial Nomenclature
  • Hierarchical Classification
  • Systematics: Evolutionary Classification
linnaeus s system of classification
Linnaeus’s System of Classification
  • Hierarchical system including seven levels or taxons
    • Species (most specific classification)
    • Genus (related species)
    • Family (related genus)
    • Order (related families)
    • Class (related orders)
    • Phylum (related classes)
    • Kingdom (related phylum--broadest category of classification)
linnaeus s system of classification1

Kingdom

Phylum

Class

Order

Family

Genus

Species

Linnaeus’s System of Classification
hierarchical classification
Hierarchical Classification
  • Taxonomic categories
    • Kingdom King
    • Phylum Philip
    • Class Came
    • Order Over
    • Family For
    • Genus Good
    • Species Spaghetti
figure 18 5 hierarchical system of classification

Coral snake

Abert squirrel

Sea star

Grizzly bear

Black bear

Giant panda

Red fox

KINGDOM Animalia

PHYLUM Chordata

CLASS Mammalia

ORDER Carnivora

FAMILY Ursidae

GENUS Ursus

SPECIES Ursus arctos

Figure 18-5 Hierarchical System of Classification
binomial nomenclature
Binomial Nomenclature
  • Carolus von Linnaeus
  • Two-word naming system-Latin
    • Genus
      • Noun, Capitalized, Underlined or Italicized
    • Species
      • Descriptive, Lower Case, Underlined or Italicized

Carolus von Linnaeus(1707-1778) Swedish scientist who laid foundation for modern taxonomy

genus species
Genus

group of closely related species

species

unique to each species within the genus

often Latinized description of some important trait

Genus species

Homo sapiens man

Ursus maritimus polar bear

Ursus arctos grizzly bear

which similarities are most important
Which similarities are most important?
  • Linnaeus group species into larger taxa according to visible similarities and differences
  • Modern biologists now group organisms into categories that represent lines of phylogeny or evolutionary relationships (Darwin), not just physical similarities
phylogenetics
Phylogenetics
  • Organism’s classification should reflect phylogeny—the evolutionary history of a species or taxon
    • Compare visible similarities among currently living species or fossils from extinct organisms
    • Compare patterns of embryonic development and ways in which different species express similar genes
    • Compare similar chromosomes, DNA or RNA
homologous vs analogous structures
Homologous vs. Analogous Structures
  • Homologous structures share a common structure
  • Analogous structures have a similar function
modern evolutionary classification
Modern Evolutionary Classification
  • Organisms determine who belongs to their species by determining with whom they will mate!
    • Species is defined as a group of organisms capable of breeding and producing viable offspring (offspring that are also capable of reproducing)
  • Taxonomic groups above the level of species are “invented” by researchers are subject to change as our understanding and information improves
evolutionary classification
Evolutionary Classification
  • Species within a genus are more closely related to each other than to species in another genus
  • Members of a genus share a recent common ancestor
  • Higher the level of the taxon, the farther back in time is the common ancestor of all the organisms in the taxon
taxonomic diagrams
Taxonomic Diagrams

Mammals

Turtles

Lizards and Snakes

Crocodiles

Birds

Mammals

Turtles

Lizards and Snakes

Crocodiles

Birds

PhylogeneticTree

Cladogram

slide20

Figure 18-13 Cladogram of Six Kingdoms and Three Domains

Section 18-3

DOMAIN ARCHAEA

DOMAIN EUKARYA

Kingdoms

Eubacteria

Archaebacteria

Protista

Plantae

Fungi

Animalia

DOMAIN BACTERIA

Go to Section:

dichotomous keys identify organisms
Dichotomous Keys Identify Organisms
  • Dichotomous keys versus evolutionary classification
  • Dichotomous keys contain pairs of contrasting descriptions.
  • After each description, the key directs the user to another pair of descriptions or identifies the organism.Example: 1. a) Is the leaf simple? Go to 2 b) Is the leaf compound? Go to 3

2.a) Are margins of the leaf jagged? Go to 4 b) Are margins of the leaf smooth? Go to 5

classification using cladograms
Classification Using Cladograms
  • Identifies and considers only those characteristics of organisms that are evolutionary innovations
    • new characteristics that arise as lineages evolve over time
    • characteristics that appear in recent parts of a linneage but not in its older members are called derived characters
    • Shared characters are features that all members of a group have in common—hair in mammals or feathers in birds
cladograms
Cladograms
  • Help scientists understand how one lineage branched from another in the course of evolution
  • Represents a type of evolutionary tree showing evolutionary relationships among a group of organisms
  • Organisms that share one or more derived characters probably inherited those characters from a common ancestor
traditional classification vs cladogram

Appendages

Conical Shells

Crustaceans

Gastropod

Crab

Crab

Limpet

Limpet

Barnacle

Barnacle

Molted exoskeleton

Segmentation

Tiny free-swimming larva

CLASSIFICATION BASED ON VISIBLE SIMILARITIES

CLADOGRAM

Traditional Classification vs Cladogram
similarities in dna and rna
Similarities in DNA and RNA
  • DNA & RNA are so similar across all forms of life, they can be used to compare organisms at their most basic level--their genes
    • The protein myosin which humans use for muscle contraction is also produced by yeast to help internal cell parts to move
    • The more similar the DNA sequences of two species--the more recently they shared a common ancestor
molecular clocks
Molecular Clocks
  • Uses DNA comparisons to estimate the length of time that two species have been evolving independently
  • Relies on a repeating process to mark time--mutation
  • The degree of dissimilarity is an indication of how long ago the two species shared a common ancestor
slide27

Living Things

Eukaryotic cells

Prokaryotic cells

are characterized by

Important characteristics

which place them in

and differing

Domain Eukarya

Cell wall structures

such as

which is subdivided into

which place them in

Kingdom Plantae

Kingdom Protista

Domain Bacteria

Domain Archaea

Kingdom Fungi

Kingdom Animalia

which coincides with

which coincides with

Kingdom Eubacteria

Kingdom Archaebacteria

kingdoms and domains
Kingdoms and Domains
  • Domains are more inclusive category--larger than a kingdom
  • Domain Eukarya
    • Kingdoms Protists, Fungi, Plants, Animals
  • Domain Bacteria
    • Kingdom Eubacteria
  • Domain Archaea
    • Kingdom Archaebacteria
kingdoms and domains1
Kingdoms and Domains

The three-domain system

Bacteria

Archaea

Eukarya

The six-kingdom system

Bacteria

Archaea

Protista

Plantae

Fungi

Animalia

The traditional five-kingdom system

Monera

Protista

Plantae

Fungi

Animalia

slide30

Figure 18-12 Key Characteristics of Kingdoms and Domains

Section 18-3

Classification of Living Things

DOMAIN

KINGDOM

CELL TYPE

CELL STRUCTURES

NUMBER OF CELLS

MODE OF NUTRITION

EXAMPLES

Bacteria

Eubacteria

Prokaryote

Cell walls with peptidoglycan

Unicellular

Autotroph or heterotroph

Streptococcus, Escherichia coli

Archaea

Archaebacteria

Prokaryote

Cell walls without peptidoglycan

Unicellular

Autotroph or heterotroph

Methanogens, halophiles

Protista

Eukaryote

Cell walls of cellulose in some; some have chloroplasts

Most unicellular; some colonial; some multicellular

Autotroph or heterotroph

Amoeba, Paramecium, slime molds, giant kelp

Fungi

Eukaryote

Cell walls of chitin

Most multicellular; some unicellular

Heterotroph

Mushrooms, yeasts

Eukarya

Plantae

Eukaryote

Cell walls of cellulose; chloroplasts

Multicellular

Autotroph

Mosses, ferns, flowering plants

Animalia

Eukaryote

No cell walls or chloroplasts

Multicellular

Heterotroph

Sponges, worms, insects, fishes, mammals

Go to Section:

domain bacteria kingdom eubacteria
Domain Bacteria: Kingdom Eubacteria
  • Unicellular and prokaryotic
  • Thick, rigid cell walls that contain peptidoglycan
  • Ecologically diverse
    • free-living soil organisms
    • deadly parasites
    • photosynthetic or heterotrophic
    • anaerobic and aerobic
domain archaea kingdom archaebacteria
Domain Archaea: Kingdom Archaebacteria
  • Unicellular and prokaryotic
  • Live in most extreme environments
    • volcanic hot springs
    • brine pools
    • black organic mud devoid of oxygen
  • Cell walls lack peptidoglycan
  • Cell membranes contain lipids unique to archaebacteria
domain eukarya kingdom protista
Domain Eukarya: Kingdom Protista
  • Eukaryotic organisms that cannot be classified as animals, plants, or fungi
  • Display greatest variety
  • Share characteristics with plants, animals, and fungi
  • Most are unicellular (except for algae)
domain eukarya kingdom fungi
Domain Eukarya: Kingdom Fungi
  • Eukaryotic
  • Heterotrophs
  • Feed on dead or decaying organic matter
    • Secrete digestive enzymes into their food source then absorb smaller food molecules into their bodies
  • Mushrooms, yeast, mildew
domain eukarya kingdom plantae
Domain Eukarya: Kingdom Plantae
  • Eukaryotic, multicellular
  • Photosynthetic autotrophs
  • Nonmotile
  • Cell walls contain cellulose
  • Include cone-bearing, flowering plants, mosses and ferns
domain eukarya kingdom animalia
Domain Eukarya:Kingdom Animalia
  • Multicellular, eukaryotic
  • Heterotrophic
  • Lack cell walls
  • Most are motile