Hi giuseppina!!
The beginings of the frogsī life is very hard, there are many
predators and environment conditions that make the surviving ratio to
low. In this situation only the species of frogs that can keep their
population in a good number could survive over ages. Here we find a
new key: over ages the environment change and these changes put on
trial the survival capabilities of the frogs; only the frogs that can
survive these tests will be able to reproduce a new generation. This
new generation of frogs will inherit these capabilities.
But, why frogs on the same species have different characteristics?
Because the genetic variation: There are patterns of natural change in
all species and these mutations occur slowly. Variation is essential
as a requirement for evolution and therefore these differential
characteristics should be inheritable.
The great variation in living things is called Diversity.
Some frogs possess physical or behavioural characteristics which aid
the success and survival in a particular environment. Because frogs
compete with anothers for resources, only the more capable will
survive. So in a given spscies of frogs, normally a few amount of the
born frogs will survive due the normal conditions of life, more will
dye because they cannot adapt to the change of the enviroment; then
the species will survive only if the chances to survive, adapt and
reproduce are high. Based on that only the species with a great
chances of diversity will survive, this goal is reaching by a birth
rate bigger than the immature individuals mortality rate. Frogsī
immature individuals mortality rate is high, so this is the cause of
the hundreds of eggs produced by the female frogs.
Note that the species that have a low rate of mortality and live more
time, like human kind or elephants, have a low birth rate; but inside
the human species regions with high infant mortality rate (IMR) have
high birth rate (BR), this is in order to give to the next generation
of the community the necessary number of individuals to have a chance
to survive.
Example:
-GABON: -GERMANY:
IMR: 93.5 deaths/1,000 live births IMR: 4.65 / 1,000
BR: 27.24 births/1,000 population BR: 8.99 / 1,000
In the explanation we use the four mainstays of the Darwin's theory:
"1. Genetic Variation: Due to genetic differences there is variation
within a population (size, color, structure, etc.). These differences
can be passed on to an individual’s offspring.
2. Overproduction: Many more organisms are born, than those that
survive and reproduce.
3. Limits on population Growth: Limited resources (food, water,
space, sunlight, etc.) creates competition
4. Differential reproduction: Organisms with features that help them
compete will be more likely to survive and reproduce.
Darwin showed that evolution can explain the diversity of life and
underlying commonalities of life’s diversity. Natural selection, as
proposed by Charles Darwin in On The Origin of Species, is an
important mechanism by which evolution proceeds. In particular,
evolution explains why organisms are adapted to their environments."
From "INTRODUCTION: THE SCIENTIFIC STUDY OF LIFE" (Powerpoint
presentation):
http://207.233.44.253/wms/reynolmj/lifesciences/lecturenote/khabio3/Chap01.ppt
"Darwin’s Theory of Evolution: The Premise.
Darwin’s Theory of Evolution states that organic life sprung from
non-organic matter exclusively through a natural mechanistic process
on a pre-biotic earth. That original life form then evolved into more
complex life forms through a natural process of random mutations and
natural selection. In a nutshell, the basic premise is that matter
acting on matter for a sufficient period of time can create anything,
whether organic or non-organic."
From "Darwin's Theory of Evolution - The Premise and Problems":
http://www.darwins-theory-of-evolution.com/
Search Strategy:
"Darwin theory"
" reproduction and evolution" darwin
I hope this helps, but if you need a clarification please post a
request of it.
Best regards.
livioflores-ga |
