RATES OF EVOLUTION
abidaThere are two models of evolution based on the rate of evolution. The concept that evolutionary changes occurs gradually over millions of years is called phyletic gradualism. Charles Darwin believes…
SPECIES AND SPECIATION
Definition of biological specie: Taxonomists classify organisms according to their similarities and differences. The fundamental unit of classification is the species. Unfortunately, it is difficult to define species. According to…
Phylum Cnidaria (COELENTERATA)
saadiaPHYLUM CNIDARIA (COELENTERATA) (Or. knide, nettle) Members of the phylum Cnidaria possess radial or biradial symmetry. Biradial symmetryis a modification of radial symmetry . In this case, a single plane…
Natural Selection Reexamined
The theory of natural selection remains very important in the modern biology. Some phenotypes are more successful. They leave more offspring than the other phenotypes. It is a natural selection.…
AND GENE FREQUENCIE
NEW CONCEPT OF EVOLUTION Natural selection operates in two ways: 1 First way: Natural selection at individual level: One way looks at characteristics of individual animals. For example, a bird…
OBJECTIVES OF EVALUATION A HISTORICAL RESPECTIVE
Multiple Choice Questions MCQs Four options are given at the end of each statement. You should encircle one option from them. Comparative anatomy was studied by: (a) Empedocles (b) Darwin …
SUBJECTIVE QUESTION OF EVALUATION A HISTORICAL RESPECTIVE
Discuss theory of acquired character of Lamarck How Geology and fossil evidence do convinced Darwin about evolution. Discuss observation of Darwin in Galapagos Islands. Describe theory of natural selection. Write…
GEOLOGICAL TIME CHART
Era,'Period Age Millions Major Biological events .c.) o N 2 SD 0 Quaternary 0.01 Subtropical forests gave way to cooler forests and grass areas. Tertiary . 65 Modern orders of…
EVIDENCE OF EVOLUTION
BIOGEOGRAPHY The study at the geographic distribution of plants and animals is called biogeography. Biogeographers explain the reason of distribution of organisms in different regions. Biogeographic studies show that life…