Did aquatic life forms get fossilised? If, yes where do we come across such fossils?
Yes, aquatic forms of life do get fossilised, infact, there are more aquatic than terrestrial fossil organisms. Such fossils of sea creatures are found in mountains as opposed to deep sea beds.
This is because the rocks in which the fossils are found used to be at the bottom of oceans. Due to the changes in the crustal plates over time, the ocean sediments were pushed up to form mountains.
What are we referring to when we say 'simple organisms' or 'complex organisms'?
These terms are used to classify organisms according to their evolutionary history.
Simple organisms refer to those organisms that have simple structural and functional organisation and are considered primitive, whereas Complex organisms refer to those organisms that have higher and complex levels of structural and functional organisation.
These are more advanced and said to have arisen from simple organisms.
How do we compute the age of a living tree?
To estimate the age of a living tree, following steps are required
(i) Measure the circumference of the tree trunk (at about 4.5 feet above the ground).
(ii) Calculate the diameter of the trunk. This is done by dividing the circumference by 3.14. Divide this (i.e., diameter) by 2 to get the radius.
(iii) Determine the growth factor. A tree's growth factor is the measurement of the width it gains annually. The trees's growth factor can be seen from the data available or by measuring the rings of a dead tree from the same species.
(iv) Multiply the diameter and the tree species average growth factor and the so done calculating suggest the approximate age of the tree in years.
Give an example for convergent evolution and identify the features towards which they are converging.
When unrelated animals converging to the same form or structure, that is very adaptive in their common environment. It is called convergent evolution, e.g., Australian marsupials and placental mammals.
Such as (placental wolf and Tasmanian wolf). These two sub-classes of mammals have adapted in similar ways to a particular food supply, locomotor skill or climate.
Their resemblances in overall shape, locomotor mode and feeding and foraging are superimposed upon different modes of reproduction, the feature that accurately reflects their distinct evolutionary relationships.
How do we compute the age of a fossil?
The age of a fossil can be computed by radioactive dating (also called radiometric dating). It is a technique based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates. Among the best known techniques are radiocarbon dating, potassium-argon dating and uranium lead dating.