Speciation is the process by which new species develop from existing species. It occurs when populations become geographically isolated, experience genetic drift through chance changes in gene frequencies, or undergo variations through natural selection. For example, genetic drift can cause gene variants to disappear and reduce genetic variation in a population. While evolution has led to more complex body designs over time, it is not a linear process of progress but rather the production of diverse life forms shaped by their environments.

1. SPECIATION
A species is a population of
organisms consisting of similar
individuals which can breed
together and produce fertile
offspring.
The process by which new species
develop from the existing species is
known as speciation.

2. FACTORS
 Geographical isolation of a population caused by
various types of barriers. The geographical
isolation leads to reproductive isolation due to
which there is no flow of genes between
separated groups of population.
 Genetic drift caused by drastic changes in the
frequencies of particular genes by chance alone.
 Variations caused in individuals due to natural
selection.

3. GENETIC DRIFT
 Genetic drift or allelic drift is the change in
the frequency of a gene variant (allele) in a
population due to random sampling. The alleles
in the offspring are a sample of those in the
parents, and chance has a role in determining
whether a given individual survives and
reproduces. Genetic drift may cause gene
variants to disappear completely and thereby
reduce genetic variation.

4. EVOLUTION OF EYES
RUDIMENTARY EYES IN PLANARIA
THEY CAN DETECT LIGHT.

5. EVOLUTION OF FEATHERS
 Pterosaurs were flying reptiles
 The presence of feathers on birds tells us that
birds are very closely related to reptiles.

6. EVOLUTION BY ARTIFICIAL
SELECTION

7. KOHLRABI &KALE

9. EVOLUTION SHOULD NOT BE EQUATED
WITH PROGRESS
EVOLUTION IS JUST THE PRODUCTION
OF DIVERSITY OF LIFE FORMS AND
SHAPING OF THIS DIVERSITY BY THE
ENVIRONMENTAL SELECTION. THE
ONLY PROGRESS IN EVOLUTION
APPEARS TO BE THAT MORE AND MORE
COMPLEX BODY DESIGNS OF
ORGANISMS HAVE EMERGED OVER THE
AGES.

10. HUMAN EVOLUTION