Basis Of Classification Flashcards
(33 cards)
The two types of habitat
Aquatic and terrestrial
Two types aquatic habitat
Freshwater and marine
State the different types of level of organization
Cellular
Tissue
Organ
Organ system
Cellular level of organization
Cells are loosely arranged
Do not firm tissue, organ or organ system
Minimum division of labour
Eg: porifera
Tissue level organization
Cells are arranged to for tissues
More complex than cellular
Eg: cnidaria and ctenophora
Organ level of organization
Tissues are arranged to form organs
More complex than tissue level organization
Eg: platyhelminthes
Organ systems level of organization
Organs arranged to form organ system
Most complex
Maximum divison of labour
Eg: nematoda to chordata
What is division of labour?
The amount of work / labour divided between cell / tissue / organ / organ system
Name the different types of body symmetry
Asymmetrical
Radial symmetry
Bilateral symmetry
Biradial symmetry
Asymmetrical body
No body symmetry at all
Can not be divided by any plane
Eg : porifera except sycon and leucosolenia
Radial symmetry
When animal body is divided into equal parts by any plane passing through the centre / central axis of body
Eg: cnidaria, ctenophora, adult echinodermata
Bilateral symmetry
When animal body is divided into equal left and right path by only one plane passing through the central axis of the body
Eg: platyhelminthes to chordata
Biradial symmetry
Biradial symmetry is kind of a sandwich which has both bilateral and radial symmetry can be divided into equal parts by two planes but is widely considered into radial symmetry
Eg: sea anemone
Which symmetry evolved first and why?
Radial symmetry evolved first during evolution of animals. Radial symmetry is helpful for aquatic animals as it helps to collect the food equally from all the sides through water and also help to remove nitrogenous wastes equally from all body sides
When did bilateral symmetry evolve?
Bilateral symmetry evolved when animals started moving and became terrestrial
Cephalization
Bilateral symmetry give rise to cephalization in animals presents of brain and other sense organ such as eyes, antenna, mouth parts etc in the anterior / head region of an animal
The two types of germinal layer
Diploblastic
Triploblastic
Diploblastic
2 layers
Outer - ectoderm
Inner - endoderm
Mesoglea in between
What is mesoglea?
Jelly / glue / cement like material in diploblastic animal between endosperm and ectoderm
Triploblastic layer
3 layers
Outer - ectoderm
Inner - endoderm
Middle - mesoderm
What is coelom?
Coelom refers to the body cavity found in some triploblastic animals between body wall and gut wall
Give an example of a triploblastic animal which is acoelomate
Platyhelminthes
What is true coelom?
Body cavity present between ectoderm and endoderm and is completely lined by mesoderm cells on both sides. These animals are known as eucoelomate
What is false / pseudo coelom?
Body cavity is present between ectoderm and endoderm but is not completely lined with mesodermal cells. Mesoderm is present in patches
