(a)i) Explain the meaning of evolution ii) Differentiate organic evolution from chemical evolution as theories of origin of life iii) What is special creation? b)...

15) a) i) Evolution is a gradual change in living organisms from simple life forms to more complex forms over a long period of time.

ii) •Organic evolution refers to the emergence of present forms of organisms gradually from pre-existing forms (some of which no longer exist).
•Chemical evolution explains the origin of life as having occurred when simple chemical compounds reacted to form the simplest life forms.

iii) Special creation maintains that the whole universe and all living organisms came into being due to the act of a supernatural being.

b)i) Fossils

•fossils are remains of organisms preserved in naturally occurring materials for many years.
•they give evidence of types of plants/animals that existed at certain geological age/long ago/millions of years ago.
•gives evidence of morphological/anatomical/structural changes that have taken place over a long period of time e. g. human skull, leg of horse.

ii) Comparative anatomy

•gives evidence of relationship among organisms/gives evidence of a common ancestry of a group of organisms.
•organisms have similar structures/organs performing the same function e. g. digestive system] urinary system/nervous system/vestigial structures and vertebrate heart.
•Divergence where the basic structural form is modified to serve different functions e.g. vertebrate forelimb/beak structure in birds/birds feet/parts of a ?ower. These are called homologous structures.
•homologous structures have a common embryonic origin but are modified to perform different functions e.g. the pentadactyl limb.
•adaptive radiation is a situation where organism have a homologous structure with common embryonic origin which is modified to perform different functions to adapt organisms to different ecological niches/habitats e.g. beaks of Darwinian finches(birds).
•Convergence is where different structures are modified to perform a similar function e.g. wings of birds and insects/eyes of humans and octopuses. These are called analogous structures.
•vestigial structures are greatly reduced in size and have ceased to function e.g. human appendix/caecium/coccix in humans, wings of kiwi (?ightless bird), presence of hind limb pad in python, halters in insects, human hair nictitating membrane in human eye, human ear muscle, pelvic girdle in whale and third digit of wing of bird.

iii) Comparative embryology

•some embryos of different animals appear very similar thus showing relationship and possibility of a common ancestry
e.g. different classes of vertebrates larvae of annelida and mollusca are similar (tocophere).

iv) Comparative serology/physiology

•these show biochemical and immunological comparisons of blood groups/components to show immunological similarities of tissues therefore showing relatedness of different organisms
e.g. antigen antibody reactions, human blood groups/Rh factor reveal some phylogenic relationship among organisms/common ancestry.

v) Geographical distribution

•organisms differ in various geographical regions.
•present continents are thought to have been a large land mass joined
together/pangea/Eurasia/Gondwanaland
present continents drifted apart from one land mass/continental drift
as a result of continental drift isolation of organisms occurred bring about different patterns of evolution

organisms in each continent evolved along different lines hence emergence of new species/divergence/convergence
Examples

•marsupials in Australia
llama, jaguar, panther in S. America
lion, camel in Africa
I tiger in Asia

vi) Cell biology (cytology)

•structures and functioning of cells are similar.
•occurrence of organelles e.g. mitochondria in all cells/both plant and animal cells.
•these point at a common ancestry.

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Anganifelix answered the question on April 17, 2018 at 14:12