Types of Organisms Flashcards
What are the three types of organisms?
Unicellular, colonial, multicellular
What are the similarities between the three types of organisms?
They are composed of cells, all of which contain membranes, cytosol, ribosomes and genetic material.
What are unicellular organisms?
These organisms have only one cell that carries out all metabolic processes. Can be pro/eukaryotic.
What are some key features of unicellular organisms?
They have a high SA:V and are directly exposed to the external environment.
Why are eukaryotic unicellular organisms more efficient than prokaryotic ones?
They have specialised organelles.
What are some examples of unicellular organisms?
Amoeba (eukaryote), bacteria (prokaryote)
What are colonial organisms?
Organisms made up of a group of identical single celled organisms, called a colony.
What are the characteristics of colonial organisms?
Each cell is able to carry out all necessary life functions.
Some colonial organisms exhibit specialised functions.
What are some examples of colonial organisms?
Jellyfish, and volvox
What is a volvox?
A colony of algal cells that arrange themselves in spheres, with daughter spheres/colonies inside. Contains 500-60,000 cells, which each have two flagella and contain chloroplasts.
In what way do volvox colonies exhibit specialisation?
Each cell in the colony has a red eyespot that can detect light. The cells on one end of the sphere have more developed eyespots that allow the colony to swim towards light.
What are multicellular organisms?
Organisms composed of may different types of specialised cells. Similar specialised cells are group together to perform specific functions. The individual cells cannot live independently of each other.
Describe the SA:V of multicellular organisms and what the effect of this is.
Multicellular organisms have a low total SA:V, and as a result, diffusion and osmosis is not enough to address nutrient and waste requirements.
Why are multicellular organisms made of many small cells?
Each cell has its own large SA:V, increasing the efficiency of diffusion and osmosis.
Why are different cells grouped into tissues in multicellular organisms?
This division of labour across different tissues allows different types of cells to carry out specific functions, which increase the efficiency of the processes within the organism, combating low SA:V
