We all know what it means to be alive and what it means to be dead.

What is the difference between being dead and being extinct? When all of the animals or plants of a given type are dead we say that this type of animal is extinct.

Sometimes a new term is useful to clarify a concept.  The opposite of dead is alive.  The opposite of extinct is extant.  Extant means that a least one member of a group of organisms is still alive.
 

Here around Nashville,  we have many living things.  We can also find remains of dead animals some of which are extinct and some of which are extant.

Consider the specimens below.  They were all alive once.  Can you tell whether the individual is dead or alive?  Can you tell whether the species is extinct or extant?  (thanks to Michael Gibson of UT Martin for help in clarifying this exercise.)
 

I found the following specimens around or in my house.  Examine each one.  Is it dead or alive?  Is it extinct or extant? How can you be sure?
 

Yeast	Bone
Dill Seed	Dill Weed

After you have thought this out for your selves, you may check my comments.
 
 

* * * * * * * * * * * * * * * * * * * *

A	B
C	D

After you have checked these out for yourselves, you can check my comments.

* * * * * * * * * * * * * * * * * * * *

I found the following specimens on the beach beside the Harpeth River at Narrows of the Harpeth in Cheatham County. Examine them carefully.  Are they dead or alive?  Are they extinct or extant?  How can you be sure?
 

 

* * * * * * * * * * * * * * * * * * * *