Everything Life Sciences Grade 10

The scientific name of our human race isHomo sapiens sapiens. We are the only surviving

members of the genusHomo— other more ancient or ancestral types have all become

extinct, such asHomo ergasterandHomo neanderthalensis.

The two-kingdom classification system devised by Linnaeus is not used today. As scientists

discovered more and more about different organisms, they expanded the system to include

many more kingdoms and groupings. Today we use a five kingdom system devised by

Whittakerin 1969 instead of the two kingdom system devised by Linnaeus. However even

today the five-kingdom system is under dispute. It is the nature of science that as more

discoveries come to light, theories will continue to be improved upon and revised.

Prokaryotes and eukaryotes DUMMY

Prokaryotes are uni- or multicellular organisms made up of cells that do not have a nuclear

envelope (pro - before, karyon - nucleus). The genetic material is not bound in a nucleus.

They also lack cell organelles such as an endoplasmic reticulum, a Golgi apparatus, lyso-

somes, and mitochondria. Prokaryotes are divided into two main groups namely the Bacteria

and the Archaea (ancient bacteria).

Eukaryotes are multicellular organisms made up of cells (eu - true, karyon - nucleus) that pos-

sess a membrane-bound nucleus (that holds genetic material) as well as membrane-bound

cell organelles. Genetic material in eukaryotes is contained within a nucleus. Eukaryotic

organisms include organisms such as plants, animals, fungi, and protists.

Table: Differences between prokaryotes and eukaryotes.

Prokaryotes Eukaryotes

Small cells Large cells

Unicellular or multicellular Often (but not always) multicellular

Genetic material is not contained

within a nucleus

Genetic material is contained in a

membrane-bound nucleus

Cells have a simple membrane internal

system but no organelles Example: no

chloroplast, no mitochondria

Cells have a distinct membrane system

with organelles Examples: Chloroplast,

mitochondria, golgi bodies

10.4 Five kingdom system

Thisis the most common way of grouping living things based on simple distinctive charac-

teristics. Classification systems are always changing as new information is made available.

Modern technologies such as Genetics makes it possible to unravel evolutionary relation-

ships to greater and greater detail. The five-kingdom system was developed by Robert H.

Whittaker in 1969 and was built on the work of previous biologists such as Carolus Lin-

naeus. The highest grouping is called a kingdom.

Living things can be classified into five major kingdoms:

302 10.4. Five kingdom system