Question

1. Define: phylogeny

2. Describe natural selection and give an example of natural selection at work in a population over time.

3. Why are vestigial structures considered to be evidence for evolution?

4. What are some other types of things cited as evidence for evolution?

5. What is the difference between microevolution and macroevolution?

Answer 1

Phylogeny - There are more than 100 million species of organisms on earth. Based on each of their morphological, biochemical and genetical data it is said that they are related to one another. This relationship is universally represented as a tree, which is called as tree of life.This tree which depicts the organism lineages over time is called as phylogeny.

Natural selection - It is the mechanism by which nature selects the best varient (phenotype) which arises due to random mutation in the nature in the course of evolution. Eg: Rabbit which runs faster will escape from its predator and will survive through generations, Algae which extracts light more efficiently will out grow the normal population of algae. This is called as natural selection.

Vestigial structures - These are sturctures which were once used by the organisms and are now useless and are not used. Since they dont harm the organism by any means they are not removed from the organism by evolution. Being unused and dipicting the ansestoral stuctures they are considered to be the evidence for evolution. Eg.  Snake skeletons containing pelvises suggest that the ancestors of snakes had legs.

Evidence for evolution - (i) Ancient organism remains (ii) Fossil layers (iii) Similarities among organisms alive (iv) Similarities in DNA and (v) Similarities of embryos are the other types of things cited as evidence for evolution.

Difference between microevolution and macroevolution - Microevolution - As the name suggest it happens in micro level where the changes happens with in one population and it is uncontroversial, documented and which happens in day to day life where existing genetic information is subjected to alteration such as rearrangement, inclusion and deletion. Eg: Two long-haired dogs producing short-haired puppy.

Macroevolution is more controversial, it is produced in large-scale (“macro”) changes. An amphibian evolving into a reptile or a reptile evolving into a bird would be examples of macroevolution.