DNA replication Process

components involved during DNA replication process :

1. DNA template
2. Enzymes :

• Helicase - unwound the two strands of DNA

• RNA primase - Synthesis the Primer to initiate the replication process and attract RNA nucleotides which bind to the DNA nucleotides of the 3'-5' strand due to the hydrogen bonds between the bases.

• DNA polymerase - read an intact DNA strand as a template and uses it to synthesize the new strand.

• Ligase -  joining of Okazaki fragments during replication.

how flowers get their color?

why flowers have wonderful color?

Actually..the color we see in flowers is the result of reflected light from various plant pigments. A group of compounds called "anthocyanidins" are the basic ingredients. They are named for flowers in which they were first found, such as the scarlet "pelargonidin" from the geranium orPelargonium, the purple "petunidin" from the Petunia, or the blue-violet "delphinidin" from the Delphinium.

Many flowers may not change color on an individual plant, but may change color, even if slightly, among locations or various conditions. Temperature affects color, hence the often more vivid colors in cool northern gardens than hot summer ones. Plant stress such as from drought, insect attack, or plant nutrition (too much or little) can also cause different levels of pigments in flowers, and so different colors.

INTRODUCTION

SPECIATION

* A process regarding the formation of new species from the pre-existing species through evolution.

* It usually depends on the isolation of two polulations as well as their genetic divergence.

Types of speciation

                                                                 

Allopatric speciation

* When two populations are Geographically isolated from one another

* separated by distance or an impassable barrier 

Eg: rising sea level

Archipelago Island

* The vast expanse of ocean that isolated the island from the main land function as a

  geographical barrier to gene flow

* Thus, over generations, the island population diverges from the mainland species.

* Individuals of the diverging population may in turn colonize other islands in the

  archipelago.

* The Hawaiian archipelago includes 19 islands and more than 100 atolls that stretch 1500

  miles in the Pacific ocean.

* The habitats on the land masses of this archipelago range from lava beds, rain forest ,

  and grasslands to dry woodlands and snow-capped peaks.

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Parapatric speciation

* Occur when one population extends across a broad region encompassing diverse habitats.


* No specific extrinsic barrier to gene flow


* Population continuous but does not mate randomly


* Individuals more likely to mate with their same Geographic neighbors.

Although continuously distributed, different flowering times have begun to reduce gene flow between metal-tolerant plants and metal-intolerant plants.

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sympatric speciation

* Population inhabiting the same geographic region speciate in the absence of a physical barrier between them.

red fish

blue fish

pictures above : Mutations in genes that affect female's perception of color of ambient light in deeper or shallower regions of lake also affect their choice of mates. 

** Female cichlids prefer to mate with brightly colored males of their own species

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Hawaiian honeycreepers

Allopatric Speciation on an Archipelagos

Akepa

Akekee

Nihoa finch

Palila

Maui Parrotbill

Apapane

Pooli

Maui Alauahio

Kauai Amakihi

Akiapolaau

Akohekohe

Liwi

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