Classification of Animals

ReviewBiology is the study of life…

So what makes something living?

All living things must:1. Be made up of at least 1 cell that

contains genetic material (DNA)2. Grow (increase in size, mature,

develop, etc.)3. Metabolize (have a need and use for

energy)4. Respond to stimuli

That’s all fine and good, but when do we get to the animals?Zoology-the study of animals

Two Major Categories:Vertebrates-have a backboneInvertebrates-do not have a backboneVertebrate or Invertebrate?

Characteristics of AnimalsMulticellular

Eukaryotes (cells with nucleus &

organelles)

Cells do not have a cell wall or chloroplastIngestive heterotrophs (take in food and

internally digest it)

Store food reserves as glycogen

Besides having the characteristics of living things, animals also:Carry out the following life processes:

1.) Locomotion:motile-can move from one location to

another on their ownsessile-cannot move from place to

place, but do have moving partsSessile

Motile

Life Processes continued 2. Ingestion-take in food3. Digestion-chemical breakdown of food4. Assimilation- using the substances

obtained from food and utilizing it for growth

5. Reproduction-producing offspring by mitosis or meiosis

6. Respiration-taking in O2 and breaking down glucose to release energy

Ingestion

_____________________So now that we’ve got all these

animals, how do we make sense of it all?

TAXONOMY!

Taxonomy-Science of classifying organisms and assigning each organism a universally accepted name.

Linnaean Classification SystemCreated by Carl Linnaeus (1707-1778)

Before Linnaeus, organisms were classified based on their type of locomotion and physical characteristicsProblem? Names were too long, and people

describe things differently.

Utilizes binomial nomenclature- a twoname system (genus and species)Scientific name

Ex: Homo sapiens

Scientific NameFirst name is Genus; second name is species

3 Rules For Scientific Name1. Italicized or underlined2. Genus name is Capitalized3. Species name is lower-case

Example: Tursiops truncatus

The Modern Classification System7 Taxa:

KingdomPhylumClassOrderFamilyGenusSpecies

Modern Evolutionary ClassificationTraditional classification used physical

appearances or anatomy, because they didn’t have access to modern technology.

Biologists now group organisms based on evolutionary descent, not just physical similarities.

These are shown with a cladogram, a diagram that shows the evolutionary relationship among a group of organisms.

Cladogram

CladogramCladistic analysis 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 lineage but not in its older members are called derived characters.

Similarities in DNA and RNAThe genes of many organisms show

important similarities at the molecular level. These similarities can be used as criteria to help determine classification.

DNA comparisons are useful on very different organisms such as yeast and primates, to indicate a common ancestry.

DNA comparisons on similar organisms helps to establish related species.

Molecular ClocksComparisons of DNA can also be used to mark

the passage of evolutionary time.A model known as a molecular clock uses DNA

comparisons to estimate the length of time that two species have been evolving independently.

This is done by observing mutations in the DNA

Natural selection is a driving force in speciation, the formation of new species.

The Three Domain SystemThe three domains are:

Bacteria—EubacteriaArchaea—ArchaebacteriaEukarya—Protists, Fungi, Plantae, Animalia