Kingdoms

Taxa…

• The seven levels of taxa today are

• kingdom,

• phylum,

• class,

• order,

• family,

• genus, and

• species.

• The example to the right shows the organization of a plant and animal:

Taxa Human Red Clover

Kingdom Animalia Plantae

Phylum Chordata Magnoliophyta

Class Mammalia Magnoliopsida

Order Primates Fabales

Family Hominidae Fabaceae

Genus Homo Trifolium

Species sapiens pratense

Kingdoms

All Six of them and how to distinguish between them!

Kingdom Characteristics Examples

Archaebacteria • Simple organisms• No nucleus• Live everywhere• Do not cause disease• Do not contain the polymer

peptidoglycan

thermophiles

Eubacteria • Simple organisms• No nucleus• Can reproduce asexually• Found everywhere• Can cause disease• Contain the polymer peptidoglycan

bacteria

Protista • Most are single celled• Some have a nucleus• Can be autotrophs, heterotrophs, or

both• Reproduce sexually and asexually• Live in aquatic or wet habitats

algae and protozoa

Kingdom Characteristics Examples

Fungi • Most are multicellular• All are heterotrophs• Reproduce sexually and asexually• Most live in terrestrial habitats

mushrooms

Plantae • All are multicellular• Most are autotrophs• Reproduce sexually and asexually• Most live in terrestrial habitats

plants

Animalia • All are multicellular• All are heterotrophs• Most reproduce sexually• Live in terrestrial or aquatic habitats

animals

Protists

The ‘kitchen sink’ or ‘junk drawer’ kingdom

General Characteristics

• Like the junk drawer in your kitchen, where you put all the things you don't really know where to put, the kingdom Protista is a catch-all for microscopic organisms.

• In this kingdom, we find organisms that are microscopic.

• Some have plant-like characteristics, while others are more animal-like, and there are some that are even like fungi.

General Characteristics

• Even though there may appear to be very different characteristics among the members of this kingdom, they do share many of the same characteristics.

• Most protists are:

• unicellular, or made of only one cell, but there are some that can form colonies;

• they are eukaryotes and contain organelles within a membrane;

• almost all reproduce by binary fission;

• they live in moist environments.

Plant-Like Protists

• Plant-like protists can be unicellular or colonial.

• The most common example of this type of protist is Euglena.

• Euglena is a single celled protist that has a flagellum and all the typical organelles found in an animal cell.

• But it also has chloroplasts for photosynthesis and a primitive eyespot that helps it find light.

• They do not have a cell wall like plant cells but they do have a pellicle that functions as a protective barrier and gives them their shape.

Plant-Like Protists

• Euglena has unique features

• It has only one flagellum where most plant-like protists have two.

• The vacuoles are known as contractile vacuoles and are used to remove excess water that diffuses into the cell.

• As water diffuses into the cell it collects in the contractile vacuole and once it is full, it contracts to excrete the water.

Plant-Like Protists

• Euglena they have chloroplasts for photosynthesis, when they are in the dark and cannot use photosynthesis they act like animal cells and will use endocytosis to ingest food.

• Reproduction is done by binary fission but instead of dividing along the equator of the cell, they divide lengthwise.

Algae

• The other major part of this group of protists is algae.

• They can be single celled and live freely in aquatic environments, or they may form colonies that resemble plants.

• The colonies are not true plants since each cell is an individual alga cell and are not specialized into the tissues that we see in plants.

• Some may also form a symbiotic relationship with other organisms, like the algae we see living with fungi to form lichens.

Algae

• Algae are divided into green, brown, and red algae.

• The green algae are typically unicellular and found free living in the upper levels of aquatic or marine environments (fresh and salt water). Green algae are often referred to as phytoplankton and are a very important primary producer in aquatic ecosystems.

• The red and brown algae often form the seaweeds that are found in marine environments. They contain other pigments besides chlorophyll to ensure that photosynthesis can occur at the depth in which they live. These pigments give them their brown or red colour

Algae

• More importantly is that algae produce about 80% of the world's oxygen when they photosynthesize.

• This also means that they consume much of the greenhouse gas, carbon dioxide, when they are doing this.

• It is important that we keep our oceans and lakes healthy since the algae living here allow us to breathe and keep global warming from getting out of control.

Animal – Like Protists

• Where plant-like protists are autotrophs, the animal-like protists are heterotrophs.

• They ingest food using endocytosis and many have features to help them collect food.

• They are found in moist or aquatic environments and can often be found in high numbers in pond water.

• The two most recognizable protozoa are Paramecium and Amoeba.

Paramecium

• Paramecium is “slipper” shaped and covered in cilia that allow them to move about.

• Cilia are small hairs that cover the surface of the cell that ripple to propel the organism forward.

• They are probably the most advanced of the protozoans.

Paramecium

• They have an oral groove that forces food down into a gullet as they swim.

• In the gullet, food is moved into a food vacuole where digestion occurs.

• The wastes from digestion are excreted through an anal pore.

• They have a contractile vacuole to remove water that flows into the organism by diffusion.

Paramecium

• They also have trichocysts, which are like poison harpoons just under the cell membrane that can be used to capture food, or to be used as a defense against predatory organisms.

• They also have two nuclei.

• The larger macronucleus is used for the daily cell activity and the smaller micronucleus controls reproduction.

Paramecium

• They reproduce using binary fission.

• Under adverse conditions, they will form a cyst that can withstand environmental extremes.

• When conditions return to normal, they emerge from the cyst and once again reproduce by binary fission.

Amoeba

• The Amoeba is the largest and simplest of the protozoans.

• It moves by the use of pseudopods that are also used for phagocytosis.

• They have two membranes. The outer membrane is called the ectoplasm that protects the organism, while the inner membrane, the endoplasm, contains the cell contents

• Amoebae are capable of reproducing by binary fission as often as once every 24 hours.

Animal – Like Protist and Disease

• While the protists living in the gut of termites help the termite digest the wood it consumes, not all protozoans are harmless or benign.

• Some are responsible for some serious illnesses.

Animal – Like Protist and Disease

• Malaria is one of those illnesses.

• It is found most often in tropical areas and it is caused by a group of protozoans known as sporozoans that have a life cycle that alternates between mosquitoes and people.

• When a mosquito that is carrying malaria bites people, the spores are transferred into the blood stream of the human where they make their way to the liver and use the liver cells to reproduce.

• When the newly formed spores rupture from the liver cells, they damage the liver

Beaver Fever and Traveler’s Trots

• In Canada we often avoid drinking untreated lake or river water. This is due to the protozoan Giardia lamblia that causes “beaver fever”. A person who has ingested this protozoan will experience stomach upset and diarrhoea; some will even have more severe symptoms.

• If you have ever travelled to a tropical location for a holiday, there is a chance you have been told not to drink the water or use any ice. This is because an amoeba known as Entamoeba histolytica may be present in the water.

Fungi – Like Protists

• Slime moulds are a very interesting organism.

• They are fungi-like protists.

• They are found in moist soil, usually under rotting logs and leaves.

• Although one of the simplest forms of protist, they have interesting lifecycles.

Fungi – Like Protists

• They can start out as single celled amoeba-like organisms and will come together to form a colony.

• The colony starts to act like a single organism.

• It will move in search for food as much as a few millimetres a day.

• As they move they resemble a living slime.

• When conditions are right, this slug-like slime will form fruiting bodies that produce spores much like fungi do.

• These spores will then mature into new slime moulds.

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