2. The number and variety of plants,
animals and other organisms that
exist in an ecosystem is known as
biodiversity
It is a measure of the variety of
organisms present in different
ecosystems
The richness of biodiversity depends
on the climatic conditions and area
of the region
Biodiversity is the result of 3.5 billion
years of evolution.
BIODIVERSITY
3. Types of biodiversity
GENETIC diversity:
genetic variability or
diversity within a
species
SPECIES
diversity:diversity
between different
species
Ecosystem
diversity:diversity
betweem different
region
4. GENETIC
DIVERSITY
is the amount of variation in
genetic material (DNA)
within a species or within a
population. The magnitude
of variation in genes of a
species increases with
increase in size and
environmental parameters
of the habitat.
5. Genetic diversity has the
following importance:
It helps in
speciation or
evolution of new
species;
It is useful in
adaptation to changes
in environmental
conditions;
It is important for
agricultural
productivity and
development
6. SPECIES DIVERSITY
It describes the variety in the number and
abundance of the species within a region
To accurately determine species diversity,
both the species richness, which is the
number of different species, and the relative
abundance, which is the number of individuals
within each species, must be considered
The species richness depends largely on
climatic conditions. When a species is
confined entirely to a particular area, it is
termed as endemic species
7. ECOSYSTEM
DIVERSITY
It describes the assemblage and
Interaction of spices living
together and the physical
environment of a given area
It relates varieties of habitats,
biotic communities ecological
processes in biosphere. It also
tells about the diversity within
the ecosystem.
9. Introduction
Evolution – includes all of the changes in the
characteristics and diversity of life that occur
throughout time.
Evolution can occur on both large and small
scales.
Microevolution
Macroevolution
10. The concept of evolution, that organisms may
change over time, was not new in Darwin’s
time.
However, it was not a widely accepted concept
because no one understood how it could work.
A mechanism was missing.
12. Variation
In any population of
organisms there is
natural variation.
Some of these
variations will allow the
organisms possessing
them to survive and
reproduce better than
those without these
particular traits.
13. Natural Selection is a
Mechanism of Evolution
The successful traits will
spread through the
population.
This change in the
frequency of alleles in
the population is
evolution.
14. Natural Selection –
High Reproductive
Potential
Darwin observed that
organisms have the potential
for very high fertility.
Organisms have the potential
to produce, and often do
produce large numbers of
offspring.
Population size would quickly
become unmanageable if all
of the offspring survived.
15. Despite this high potential fertility, natural
populations usually remain constant in
size, except for small fluctuations.
Not all of the potential offspring survive.
Natural Selection – Population Size
Remains Constant
16. Natural Selection – Limited
Resources
Resources that
organisms need
to survive are
limited.
Food, water,
shelter, nesting
sites, etc.
17. Natural Selection – Competition
If there are not enough
resources for all of the
individuals, there will
be competition for
those resources.
Survivors represent a
small part of the
individuals produced
each generation.
18. Natural Selection – Populations
Show Variation
Which individuals will survive is often not a matter of
luck.
Populations show variation – individuals are not
identical.
They differ in many different traits.
19. Some of the variation
between individuals
in the population is
heritable.
It can be passed
down from one
generation to the
next.
Natural Selection – Variation is
Heritable
20. Some of the traits
found in the
population enhance
the survival and
reproduction of the
organisms
possessing them.
Natural Selection – Some traits
Enhance Survival
21. Natural Selection – Adaptation
The favored traits will
spread through the
population.
Over many generations, the
species will become adapted
to its environment.
Over time, these changes can
lead to the formation of a
new species.
22. Adaptation
A species may become adapted to its
environment in response to environmental
pressures.
A trait may be favored due to enhanced survival or
reproduction when faced with a particular aspect of
the environment.
When an environment changes, or when individuals
move to a new environment, natural selection may
result in adaptation to the new conditions.
Sometimes this results in a new species.
23. Populations Evolve
Individuals do not
evolve; populations
evolve.
Evolution is measured
as changes in relative
proportions of heritable
variations in a
population over several
generations.
24. Natural Selection – Important Points
Natural selection can only work on
heritable traits.
Acquired traits are not heritable and are
not subject to natural selection.
25. Environmental factors are variable.
A trait that is beneficial in one place or time
may be detrimental in another place or time.
Natural Selection – Important Points (2)
26. Natural selection is
not random. It
occurs in response
to environmental
pressures and
results in
adaptation.
Natural Selection – Important
Points (3)
27. Natural Selection – Important
Points (4)
When natural selection is
occurring, some individuals are
having better reproductive
success than others.
Alleles are being passed to the
next generation in frequencies
that are different from the
current generation.
34. Geologic Processes Affects Natural
Selection
The tectonic plates have drifted slowly on the planets
mantle.
35. Effects
The location of continents and oceanic
basins have greatly influenced the earth’s
climate and thus helped to determined
where animals and plants can live.
Species has allowed to move , adapt a new
environment and form new species to
natural selection.
36. Climate change and Catastrophes
affect natural selection
Cooled
Covered with ice
38. How do speciation , extinction and
human activities affects biodiversity?
39. It can decrease biodiversity by causing
premature extinction of species and
by destroying or degrading habitats
needed for the development of new
species
40. How do new species evolve
It is by NATURAL SELECTION
and also called as
SPECIATION.
SPECIATION- it is a process
where a specie splits into 2 or
more different kinds of
species.
41. 2 Kinds of Speciation
1. Geographic Isolation-
a specie become
physically isolated from
one another for a long
period of time.
42. 2. Reproductive
Isolation
- mutation and
change by
natural selection
operate
independently in
the gene pools of
geographically
isolated
populations.
43.
44. Extinction is forever
Extinction- a process in which an entire
specie ceases to exist or a population of a
specie becomes extinct or gone over a large
region but not globally.
Ex. Endemic specie- specie that found only
in one area.
45. 2 kinds of extinction
1. Background extinction- species have
disappeared at a low rate (1 to 5 species
extinct)
2. Mass extinction.- species have
disappeared at a high rate (a large group of
specie extinct)
47. Species diversity is a major component of
biodiversity and tends to increase the
sustainability of some ecosystems.
Species diversity includes the variety and
abundance of specie in a particular place.
- species richness
- species evenness
52. It is the natures ultimate survivors lived
around 350 million years.
They survived because they can eat
anything that they see.
3500 different kinds of cockroaches
They also have 2000 lenses in their eyes
And did you know that Asian cockroaches
can offspring a 10 million eggs in their
entire life.
53. Niches can be occupied by native
and nonnative species.
Native species
Nonnative species
-species that are normally live and thrive
in a particular ecosystem.
-species that migrating or accidentally
introduced into an ecosystem
54. Indicator Species serve as biological
smoke alarms
Birds are also excellent as biological
indicators because they are found almost
everywhere and they are affected quickly by
environmental changes.
GSE 415 EARTH/ENVIRONMENTAL SCIENCE
55. Foundation Species- a major role in shaping
community by creating and enhancing their
habitats in ways that benefit other species.
56. Keystone and foundation species
play important roles in their
ecosystem.
Keystone species-
whose roles have a
large effect on the
types and abundance
of the other specie in
an ecosystem.
