ANIMAL DIVERSITY Flashcards
biodiversity
refers to the variety of life on earth
how are animals sorted
animals are sorted according to their simillarities and differences
kingdom that animals belong and whats it divided into
kingdom anamalia where its divided into phyla which is based on the differences in their basic body plan
a phylogenetic tree
a diagram showing the evolutionary relationships between ancestral groups or organisms and their descendants
body plan
a structural characteristics of an organism that seperates it from other organisms or groups of organisms
important feautures of body plans
- symmetry
- cephalisation
- embryonic tissue layers
- development of a coelom
- number of gut openings
6 blood systems
3 types of body symmetry
- asymmetrical
- radial symmetry
- bilateral symmetry
characteristics of asymmetrical symmetry
there is no symmetry and the organism is most likely unicellular, has no pattern and cant be divided in halves
characteristics of radial symmetry
- body plan can be cut to get = halves
- can get food in any direction and sensory receptors are evenly distributed around the body
- usually sessile or can move around a little
example of an organism with radial symmetry
jelly-fish
characteristics of bilateral symmetry
- body plan can be divided into 2 = hallves in only 1 plane
2. is usually active and constantly moves around to search for food, to mate and interact with the environment
example of an organism with bilateral symmetry
humans
cephalisation
when most of the sense organs, feeding appendages and the brain are near the anterior part of the body
function of cephalisation in organisms
one side of the brain is a concentration of nerves and tissue and functions to receive and interprate stimuli
what are the first tissue layers formed in the embryo called
germ layers(which differentiate into different organs)
what does the primary germ consists of
- the ectoderm(outer layer)
2. the endoderm(inner layer)
what does the ectoderm develop into
develops into skin or epethilium and the nervous system of the animal
what does the endoderm form
the digestive system
what are animals that have these 2 layers called
diploblastic animals
what does the secondary germ consists of
the mesoderm, which develops between the endoderm and ectoderm
what does the mesoderm develop into
it develops into connective tissue, bone, blood, reproductive organs, cartilage blood and lymphatic systems
what a animals that have three tissue layers called
triploblastic animals
what is a coelom
a fluid filled body cavity that develops in the mesoderm tissue layer in more advanced animals
what are animals without coeloms called
acoelomate
what do coelomate animals have
they have a body cavity or coelom in their mesodermal tissue layer
advantage of coelom
- allows complex organs to develop
- coelom fluid helps transports nutrients and waste in the body
- allows the creation of a hydrostatic force to be generated for movement in soft-bodied animals
disadvantages of coelom
there is insufficient transport of;
- gases from and to the body wall
- nutrients from digestive system to body wall
- nitrogenous waste from internal organs to excretory organs and therefore needs a circulatory system
how do animals with a blood gut consume food
through the opening(mouth) and excrete waste through the same opening
disadvantages of a blind gut
- it limits the amount of food that these animals can consume
- digestin is not specialised
- they must excrete the waste from their digestive system before they can consume more food
how do animals with a through gut opening consume and excrete food
animals with two openings to the gut consume food thrugh a mouth opening and excrete waste through another opening called the anus
advantages of a through gut
- food can be consumed continiously because it moves through the digestive system
- digested and undigested food do not mix
- sections of the digestive system can also specialise to improve the efficiency of the digestive process
circulation system
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