TO FOLLOW THESE SLIDES you will learn about the adaptive radiations involve in evolution . yo will learn about the parallel adaptations and its types speciation role in the evolution factors key innvations to imrove the article involving examples Founder events Adaptive plasticity process of adaptive radiation Factors promote adaptive radiations Factors underlying adaptive radiations defined by 0.S OSBORN ecological space geological climatological Islands examplrs: 1.Darwin Finches 2.Cichlid fish genome -adaptive evolution, Stanford scientists 3.Anolis Lizards Factors promote adaptive radiations 1.Generally speaking, adaptive radiations occur when new, unoccupied ecological niches become accessible to a founder population. This can happen after a mass extinction during which the previous occupiers of those niches died out. t can also happen when a colonizing species arrives at an island. (For instance the ancestor of the honeycreepers in Hawaii, or of Darwin's "finches" in the Galapagos) Honey creeper Change feeding habitat At least 56 species of Hawaiian honeycreepers known to have existed, although all but 18 of them are now extinct. Lack of competition. When a species enters an adaptive zone, it is poorly equipped to compete with species that have become adapted to the same niche. For example, mudskippers are fish that are making a living on land, but they are marine fish and they don't have to compete against frogs and salamanders, which are restricted to fresh water. That is why we don't see freshwater mudskippers. process of adaptive radiation Ecological Release Colonization of species. Taxon cycle Habitat varying as population expand- species dispersal. Adaptive plasticity Phenotypic plasticity(behavior change) Property of an individual or genotype that may be adaptive, maladaptive or neutral with regard to an individual's fitness. The particular way an individual's (or genotype's) phenotype varies across environments can be described as a reaction norm (Single genotype-phenotypic expression) Speciation in adaptive radiation Founder events

1. Presentation on : Adaptive radiations
Presented by : Rabia Shehzadi
Presented to : Dr. Shumaila
Msc.II

2. Adaptive radiations

3. Introduction
Adaptive radiation is one of the most important
outcomes of the process of evolution.
The term itself was first used by H. F. Osborn.
parallel adaptations
convergence of species groups on different land
masses.

4. Parallel adaptations
Parallel evolution -wherein two or more
species in the same environment develop
similar adaptation or characteristics.
 Parallel evolution is similar to convergent
evolution in a way that two unrelated species
evolved similar traits

5. Definition
The evolutionary diversification -single ancestral
lineage into various forms.
Each adaptively specialized to a specific
environmental niche.
 Adaptive radiation generally proceeds most rapidly
in environments.
 where there are numerous unoccupied niches
competition for resources is minimal.

6. Factors underlying adaptive radiations
The most widely recognized “trigger” for
adaptive radiation is the opening up of
ecological space.
 This may occur following evolution of a key
innovation or when climatological or
geological changes lead to the appearance of
novel environments.

7. Islands of all types including in such
dynamic environment contribute to the
emergence of novel evolutionary
changes.

8. Key innovations
1. 1. The term was first used in 1949 by H.F Osborn
who defined it as "key adjustments in the
morphological and physiological mechanism which
are essential to the origin of new major groups
2. A key innovation is an evolutionary change in
individual traits that is causally linked to an increased
diversification rate in the resulting clade.

9. 3.Adaptive breakthrough or key adaptation, is a novel
phenotypic trait that allows subsequent radiation and success of a
taxonomic group.
4.Typically they bring new abilities that allows the taxa to
rapidly diversify and invade niches that were not previously
available.
5.The phenomenon helps to explain how some taxa are much
more diverse and have many more species than their sister taxa.

10. Examples
1.Darwin Finches
Common ancestor –Galapagos
 About two million years ago.
Evolved into 15 recognized species
differing in body size, beak shape, song and feeding behavior.
Changes in the size and form of the beak
Utilize different food resources such us insects, seeds, nectar from
cactus flowers all driven by Darwinian selection.

11. 2.Cichlid fish genome -adaptive evolution,
Stanford scientists
Roughly 40 million years ago, a handful of species of
fish
Nile River went into three lakes in Africa and
experienced an
Unusual flurry of evolution.
In one of these lakes as many as 500 new species
emerged in fewer than 100,000 years.

12. Adapted to eat the scales of other fish.
Others have adaptations that allow them to live among rocks and eat
prey, shells included.
 Reproduction purposes
 To get at how this spectacular "adaptive radiation" – the process by
which multiple species evolve from an ancestor through adaptation –
occurred so quickly among Cichild fish.
 The scientists analyzed the genomes of these five species, starting
with the Nile which represented the ancestral lineage.

13. 3.Anolis Lizards
In both adaptive radiation and convergent evolution.
These divergences in habitat are accompanied by
morphological changes primarily related to moving having
short limbs, while trunk ecomorphs have long limbs.

14. In addition, these patterns repeat on numerous
islands, with animals in similar habitats
converging on similar body forms repeatedly.
This demonstrates adaptive radiation can
actually be predictable based on habitat
encountered.

15. Factors promote adaptive radiations
1.Generally speaking, adaptive radiations occur
when new, unoccupied ecological niches become
accessible to a founder population.
This can happen after a mass extinction during
which the previous occupiers of those niches died
out.

16. 2. It can also happen when a colonizing species arrives at an island. (For
instance the ancestor of the honeycreepers in Hawaii, or of Darwin's
"finches" in the Galapagos)
Honey creeper
Change feeding habitat
At least 56 species of Hawaiian honeycreepers known to have existed,
although all but 18 of them are now extinct.

17. 3. It can also happen when a founding population evolves some
physiological innovation that brings it within reach of new niches.
Examples would include the bird or bat wing, or the flower as a means
of attracting insects for pollination.

18. 4.Lack of competition. When a species enters an adaptive zone, it is
poorly equipped to compete with species that have become adapted to the
same niche.
For example, mudskippers are fish that are making a living on land, but
they are marine fish and they don't have to compete against frogs and
salamanders, which are restricted to fresh water. That is why we don't
see freshwater mudskippers.

19. process of adaptive radiation
Ecological Release
 Ecological release has been inferred to occur at the
outset of adaptive radiation. This sort of release is the
expansion of range, habitat or resource usage by an
organism when it reaches a community from which
competitors, predators or parasites may be lacking.

20. Colonization of species.
Taxon cycle
Habitat varying as population expand- species dispersal.

21. Adaptive plasticity
Phenotypic plasticity(behavior change)
Property of an individual or genotype that may be
adaptive, maladaptive or neutral with regard to an
individual's fitness.
The particular way an individual's (or genotype's)
phenotype varies across environments can be
described as a reaction norm (Single genotype-phenotypic
expression)

22. Speciation in adaptive radiation
SPECIATION : Formation of a new and distinct
spp. In course of evolution.
mechanisms of speciation involve the creation of
one or two species from another species over a
long period of time.
 This ratio of at most 2 species emerging from 1
original species.

23. Founder events
 A founder event occurs when a new population is composed of only a few colonists
 inevitably carrying only a small sample of the genetic diversity of the parent population.
 This small population size means that the colony may have reduced genetic variation
 Non-random sample of the genes relative to the original population.

24. thanks