Biodiversity and Classification Notes

Biodiversity and Classification

Biodiversity and Endemism

Indigenous Species: Species that occur naturally in a specific area.
- These species may be found in many different places on Earth.
Alien/Exotic Species: Species brought into an area.
Endemic Species: Indigenous species found nowhere else in the world.

Biodiversity in South Africa

South Africa occupies only 1% of Earth's total land mass but contains 10% of the world's biodiversity.
South Africa is ranked 3rd in the world in terms of biodiversity.
The country has a large number of endemic species and is the 24th richest country in the world in terms of endemic species.

Organisms on Earth

A great variety of organisms co-inhabit the Earth.
These organisms occur in many different forms and sizes, some invisible to the naked eye.
They are genetically different.
Different species can live in a variety of different habitats.

Classification and Taxonomy

Classification: Grouping and sorting things according to similarities and differences.
Taxonomy: The science of naming and classifying a wide range of living things.

History of Classification

Many scientists have classified living organisms.
Up until the mid-19th century, physical appearance was the primary criterion for classification.
Anatomy was studied, and organisms were grouped based on similarities and differences.
Classification changes as more information is gathered and technology advances.

Early Classification Methods

Living things were classified in many different ways:
- Useful or not
- Domestic/wild/creeping/flying and sea animals

Classification by Aristotle

Aristotle (384-322 BCE): Classified living organisms into two groups: plants and animals.
- Plants were further classified into herbs, shrubs, or trees.
- Animals were classified into those with red blood and those without.
- He also classified animals according to modes of locomotion: flying, walking, or swimming.
- Aristotle classified about 1000 plants and animals.

Carl Linnaeus: Two Kingdom System

Carl Linnaeus developed the Two Kingdom Classification System, which included:
- Kingdom Plantae (Plants)
  - Able to make their own food.
  - Have a cell wall.
  - Sedentary.
- Kingdom Animalia (Animals)
  - Not able to make their own food.
  - No cell wall.
  - Motile.

Binomial System

Carl Linnaeus also developed the Binomial System of naming organisms.
Each organism is given two names: a generic name (genus) and a specific name (species).
- The genus name starts with a capital letter, and the species name starts with a small letter.
- When printed, it is written in italics.
- When written, both names are underlined.
Examples:
- Loxodonta africa
- Grus paradisea

Nested System of Carl Linnaeus

Similar species are placed in the same genera.
Similar genera are placed in the same family.
Similar families are placed in the same order.
Similar orders are placed in the same class.
Similar classes are placed in the same phylum.
Similar phyla are placed in the same kingdom.

Example of Nested/Hierarchical System

Humans vs. Chimpanzees
- Kingdom: Animalia for both
- Phylum: Chordata for both
- Class: Mammalia for both
- Order: Primates for both
- Family: Hominidae (Humans), Pongidae (Chimpanzees)
- Genus: Homo (Humans), Pan (Chimpanzees)
- Species: sapiens (Humans), troglodytes (Chimpanzees)

Five Kingdom Classification System

Proposed by Robert Whittaker in the 1950s.
Based on fundamental differences between groups of organisms.
Still widely used today.

Separation of Organisms

Organisms were separated based on:
- Prokaryote/Eukaryote: Prokaryotes placed into Kingdom Monera.
- Multicellular eukaryotes were placed into three kingdoms: Plantae, Animalia, Fungi.
- Eukaryotic organisms that did not fit into the three kingdoms were placed into Kingdom Protista.

Classification Diagram

All living organisms are either Prokaryotes (no true nuclei) or Eukaryotes (true nuclei).
- Kingdom Monera: Prokaryotes
- Kingdom Protista: Unicellular Eukaryotes
- Kingdom Plantae: Multicellular, Autotrophic Eukaryotes
- Kingdom Fungi: Multicellular, Heterotrophic Eukaryotes (food is digested then taken in)
- Kingdom Animalia: Multicellular, Heterotrophic Eukaryotes (food is taken in then digested)

Cell Types

Prokaryotic cells vs. Eukaryotic cells

Cellularity

Unicellular: Made up of only one cell.
Multicellular: Made up of many cells.

Three Domain System of Classification

Classification systems are evaluated and changed as more information becomes available.
Scientists have recently proposed the Three Domain System of Classification.

Three Domain System Details

All eukaryotes are placed in the Domain Eukarya.
Prokaryotes are divided into two domains:
- Domain Archaea
- Domain Eubacteria
Domain Eubacteria consists of the true bacteria.
Domain Archaea is made of prokaryotes that are different from true bacteria in both their genetic makeup and their metabolism.

Five Kingdoms: Main Characteristics

Kingdom Monera

Made up of bacteria.
Unicellular and microscopic.
Prokaryotes.
Autotrophic or heterotrophic.

Kingdom Protista

Includes slime molds, protozoans, and algae.
Mostly unicellular, but some are multicellular.
All are eukaryotes.
Plant-like: algae.
Animal-like: protozoans like Amoeba.
Slime molds.

Kingdom Fungi

Mushrooms, yeast, and mold.
Heterotrophic.
May be unicellular (yeast) or multicellular.
They first digest before they ingest (take in).

Kingdom Plantae (Plants)

Eukaryotic.
Multicellular.
Distinct cell wall made of cellulose.
Contains chlorophyll (autotrophic).
Sexual and asexual reproduction.

Kingdom Animalia (Animals)

Eukaryotic.
Multicellular.
No cell wall or chloroplast.
Heterotrophic.
Reproduce sexually and asexually.
First ingest, then digest.

Classification Tools

Using a classification key

Pictorial Keys

Have illustrations (pictures, photographs, or a combination).
Organisms are identified by comparing them to the illustrations.

Dichotomous Key

A form of hierarchical grouping.
Involves making decisions in a series of steps, from general to specific differences.
Dichotomous because there are always two choices.

Dichotomous Key Examples

Example 1:
1. a. wings covered by an exoskeleton - go to step 2
  b. wings freely observed - Go to step 3
2. a. body has a round shape ………ladybug (a red beetle with black spots)
  b. body has an elongated shape ……….grasshopper (a green insect that hops)
3. a. wings point out from the side of the body dragonfly (an insect that is 10-15 cm long and lives in marshes)
  b. wings point to the posterior of the body …housefly (a flying insect with red eyes and an annoying buzz)
Example 2 (Mini-Beast Key):
- Flowchart-style dichotomous key based on characteristics like wings, legs, shell, and activity patterns to identify different mini-beasts (centipede, spider, moth/butterfly, worm, snail).
Example 3 (Bird Dichotomous Key):
1. a. Bird lives on land or ice - Go to 2
  b. Bird lives in water - Go to 5
2. a. Bird has talons - Go to 3
  b. Bird does not have talons - Go to 4
3. a. Bird can rotate head back 180° - Barn owl
  b. Bird cannot rotate head 180° - Hawk
4. a. Bird has short, stubby tail and yellow splotch on neck - Emperor penguin
  b. Bird has long-feathered tail and bright blue neck - Peacock
5. a. Bird has long, stilt-like legs - Flamingo
  b. Bird has shorter legs - Duck

Verbal Keys

Clues are in the form of statements or questions of characteristics.
By answering the questions or following the statements, the correct taxon is identified.

Verbal Key Example: Five Kingdoms

Do the organisms have a definite nucleus?
- YES: Go to question 2.
- NO: Kingdom Monera.
Is the organism multicellular or unicellular?
- If it is unicellular then it is Kingdom Protista
- If it is multicellular then go to question 3
Is the organism autotrophic?
- If it is then it is Kingdom Plantae
- If NO then go to question 4
Does the organism digest food outside its body and then take it in?
- If it does then it is Kingdom Fungi
- If NO then it is Kingdom Animalia