IB Biology SL - Classification

Info card: Natural Classification

Basically classification lets you identify species with kingdom, phylum, class and order, by characteristics shared between species.

• In a natural classification, the genus and accompanying higher taxa consist of all the species that have evolved from a common ancestor, members of a genus have a common ancestor

What is unnatural classification?

Groups birds, bats, insects, wings evolved separately

Why can natural classification be problematic?

Sometimes you can make mistakes identifying convergent vs. divergent evolution based on physical structures

How does the hierarchy of taxa go? What does taxon mean?

Kingdom, Phylum, Class, Order, Family, Genus, Species

A group of something

What are the three domains that organisms are classified into?

Eubacteria - Bacteria

Archaea - Archaeans

Eukaryote - Eukaryotes

Note: Viruses are not classified as organisms

The domain eukaryote is divided into four kingdoms. What are they?

Protoctista

Fungi

Plantae

Animalia

What’s the taxa hierarchy in terms of places in the world?

Domain

• Union

Kingdom

• Country

Phylum

• State/Region

Class

• County

Order

• City

Family

• Neighborhood

Genus

• Street

Species

• House

How does the binomial nomenclature system work?

Each organism is given a name based on two words

• Generic name, genus

  • Beginning with a capital letter

• Specific name, species

  • Begins with a lowercase letter

In print this name is always italicized

The species name is always written in full whereas the genus name is often abbreviated, ex. E. coli

What are the phyla of the Kingdom Plantae?

• Bryophyta

• Filicinophyta

• Coniferophyta

• Angiospermophyta

Describe Bryophyta

Mosses

• No vascular tissue, no roots either but they have similar structures to roots

• Simple leaves & stems

• Spores are produced in a capsule, then develop at the end of a stalk

Describe Filicinophyta

Ferns

• They have vascular tissue, roots, leaves and non-woody stems

• Leaves are usually curled up in a bud

• Often divided into pairs of leaflets

  • Spores produced in sporangia on the underside of leaves

Describe Coniferophyta

Conifers, cones

• Have vascular tissue, shrubs or trees with roots, leaves and woody stems

• Leaves are often narrow with a thick waxy cuticle

• Seed develops from ovules on the surface of scales of female cones

• Male cones produce pollen

Describe Angiospermophyta

Flowering plants

• Have vascular tissue

• Usually roots, leaves and stems

• Stems of shrubs and trees are woody

• Seeds are produced, developing from ovules inside the ovary

• Fruits develop from the ovaries to disperse seeds

What are the 7 phyla of animals you have to know?

1. Porifera

2. Cnidaria

3. Platyhelminthes

4. Annelida

5. Mollusca

6. Arthropoda

7. Chordata

Describe Porifera

• No clear symmetry

• Attached to a surface

• Pores through body

• No mouth or anus

• Examples; sponges

Describe Cnidaria

• Radially symmetric

• Tentacles

• Stinging cells

• Mouth but no anus

• Examples; jellyfish, corals, sea anemones

Describe Platyhelminthes

• Bilaterally symmetric

• Flat bodies

• Unsegmented

• Mouth but no anus

• Examples; planaria, tapeworms, liverflukes

Describe Annelida

• Bilaterally symmetric

• Bristles often present

• Segmented

• Mouth and anus

  • Examples; earthworms, leeches, ragworms

Describe Mollusca

• Muscular foot and mantle

• Shell usually present

• Segmentation not visible

• Mouth and anus

• Examples; sluges, snails, clams, squids

Describe Arthropoda

• Bilaterally symmetric

• Exoskeleton

• Segmented

• Jointed Appendages

• Examples; insects, spiders, crabs, millipedes

Describe Chordata

• Bilaterally symmetric

• Endoskeleton

• Segmentation not visible

• Mouth and anus

• Examples; birds, mammals, amphibians, reptiles and fish

What 5 classes of phylum chordata do you need to know?

• Fish

• Amphibians

• Reptiles

• Birds

• Mammals

Describe Fish

• Scales with bony plates in the school

• Gills covered by operculum, one gill slit

• No limbs

• Fins supported by rays

• Eggs and sperm released for external fertilization

• Swim bladder contains gas for buoyancy

• Doesn’t maintain constant body temperature

Describe Amphibians

• Soft/Mosit skin permeable to water and gas

• Simple lungs with folds and moist skin for gas exchange

• Tetrapods with pentadactyl limbs

• Four legs in adulthood

• Eggs and sperm released for external fertilization, eggs coated in protective jelly

• Larva in water - Adult on land usually

• No constant body temp maintenance

Describe reptiles

• Impermeable skin covered in keratin scales

• Lungs with extensive folding to increase surface area

• Tetrapods with pentadactyl limbs

• Four legs in most species

• Sperm passed into female for internal fertilization

• Females lay eggs with soft shells

• Teeth all of one type, with no living parts

• No constant body temp maintenance

Describe Birds

• Skin with feathers made of keratin

• Lungs with parabronchial tubes, ventilated with air sacs

• Tetrapods with pendadactyl limbs

• Two legs and two wings

• Sperm passed into female for internal fertilization

• Females lay eggs with hard shells

• Beak but no teeth

  • Maintain constant body temp

Describe Mammals

• Skin has follicles with hair made of keratin

• Lungs with alveoli, ventilated using ribs and a diaphragm

• tetrapods with pentadactyl limbs

• Four legs in most, or two legs and wings/arms

• Sperm passed into female for internal fertilization

• Most give birth to live young and feed young with milk from mammary glands

• Teeth of different types with living cores

• Maintain constant body temperature