月度归档： 2013 年 9 月

Illustrations of wild animals [insect 4 Praying Mantids]

螳螂目 MANTODEA

Mantodea (Mantids / Praying Mantids)

The name Mantodea is derived from “mantis”, the Greek word for these insects.

  • Classification & Distribution

Hemimetabola

  • incomplete development (egg, nymph, adult)

Orthopteroid

  • closely related to Orthoptera and Blattodea

Distribution: Common in tropical and subtropical climates.

WORLDWIDE
Number of Families
8
Number of Species
~1800
  • Life History & Ecology

Mantids have elongate bodies that are specialized for a predatory lifestyle:  long front legs with spines for catching and holding prey, a head that can turn from side to side, and cryptic coloration for hiding in foliage or flowers.

Mantids are most abundant and most diverse in the tropics; there are only 5 species commonly collected in the United States and 3 of these have been imported from abroad.

  • Physical Features
mantid image

Adults:

  • Filiform antennae
  • Head triangular with well-developed compound eyes
  • Mouthparts mandibulate, hypognathous
  • Prothorax elongate with large, spiny front legs adapted for catching prey
  • Front wings thickened, more slender than hind wings
  • Tarsi 5-segmented
  • Cerci short, multi-segmented

Immatures:

  • Structurally similar to adults
  • Developing wingpads often visible on thorax
  • Major Families 
      • Mantidae — this family includes all of the common North American mantids.

The name mantid refers only to members of the family Mantidae.

  • Bug Bytes
    • Mantids are the only insects that can turn their head from side to side without moving any other part of the body. Many humans mistakenly interpret this behavior as a sign of intelligence.
    • A female mantid may eat her mate while he is still linked with her in copulo.  This behavior is probably more common in captivity than in the wild.
    • Most mantids are cryptically colored to blend with their environment.  A pink Malaysian species spends most of its time hunting for prey on pink orchids.
    • Although mantids usually feed on insect prey, they have been known to catch and eat small frogs, lizards, and even birds

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↑Quoted from the General Entomology course
at North Carolina State University >Resource Library > Compendium > Mantodea (© 2009 by John R. Meyer; Last Updated: 8 April 2009)

>Learn more about pray mantids (mantodearesearch.com)

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螳科 Mantidae
  1. 大刀螳螂Tenodera aridifolia

2.  中华刀螳Tenodera sinensis

3. 短胸大刀螳Tenodera brevicollis

  1. 棕静螳 Statilia maculata
  1. 广斧螳 Hieroduia patellifera
长颈螳科  Vatidae

中华屏顶螳Kishinouyeum sinensae

the blueprint of life[1]

Of course the blueprint of life is DNA.

DNA is important because it is the genetic material ←contain all the info for the synthesis and functioning of a living form duplicate and passes through to the next generation.

Hearing this Annie questioned herself: DNA is not the genetic for ALL viruses. RNA “blueprints” for the rest of the viruses. Virus, though not even having a cell structure, is a form of life. So why not be fair, and say the blueprint of life are DNA and RNA?

Professor Dong continued,

Proofs:

  1. Bacterial Transformation Experiment

—Griffith, 1928

Professor: So what is the transforming principle? 

Annie: It could be a cool type of enzyme that moved the toxic part of S strain onto R strain…

Professor: Well, Enzyme did help a lot in the experiment we’ll talk about later, but it is not the hero of the story.

Annie: So what’s the story?

Professor:

—Avery et al., 1944

slide shown by Prof. Dong ,AVERY REPEATED GRIFFITH’S EXPERIMENT WITH MODIFICATION

Only DNA is responsible for the transformation.

Annie thought: Well, there still existed possibilities that DNA and some other things that were not sugar, lipid or protein cooperated to complete the transformation… The “other things” also contributed to the transformation but could not complete it without DNA?  In this case DNA is not the only one that is responsible,  

  1. T2 Bacteriophage Infection (Blender Experiment)

—Hershey &Chase, 1952

Experiment 1

Experiment 2

Radioactive labeling of proteins and DNA

The professor continued. So now let’s go deeper and see the chemical composition of DNA.

A 5-carbon sugar , hand in hand with base group and phosphorous group, thought Annie.

It’s not that simple as you learned in high school, said the professor. We need to know the chemical composition of the base group, deoxyribon and phosphorous group as well.

sugar group
slide shown by Prof. Dong,SUGAR GROUP

 Professor:

Base
slide shown by Prof. Dong,BASE GROUPS

Annie thought: Pyrimid-ine, Could it have anything to do with the Pyramid in Egypt?

The professor was explaining the structure and Annie didn’t interrupt him with her question.

After class, Annie searched the Internet for an answer, and this is what she found.

 The professor continued.

Bonds

P group——phosphester bond–—Sugar—–glycosidic bond—–B group

Mendel’s Genetics[2]: The monohybrid cross

Keywords:

  • Phenotype

Any character (trait) which can be shown to be inherited, such as eye color, leaf shape or an inherited disease, such a cystic fibrosis, is referred to as a phenotype.

Description: A fly may be described as having a red-eyed phenotype. A child may be described as displaying the cystic fibrosis phenotype.

  •  Genotype

The pattern of genes that are responsible for a particular phenotype in a individual is referred to as genotype.

  • Dominance

In hybrids between two individuals displaying different phenotypes, only one phenotype may be observed. This phenotype is referred to as the dominant trait and the un-shown one the recessive.

For instance, if the wife has wide eyes while the husband has small eyes, and their little girl has wide eyes, then the wide eyes are dominant to small eyes.

  •  Pure-breeding lines

Organisms which have been inbred for many generations in which a certain phenotype remain the same.Pedigree breeds of dogs or cats are commonplace examples of pure-breeding lines.

A puppy from two purebred dogs of the same breed, for example, will exhibit the traits of its parents, and not the traits of all breeds in the subject breed’s ancestry.

  • Homozygous: Individuals with two identical copies of a gene.

“True breeding (pure-breedind) organisms are always homozygous for the traits that are to be held constant.”

  • Heterozygous: Individuals with two different copies of the gene.
  • Alleles: The different variants of a gene.

====================================================

Mendel made a cross between two pure-breeding lines of pea plants, one of which had violet petals and the other white petals. The hybrids produced in this cross were referred to as the F1 (first filial) generation.

In Mendel’s experiment, the ratio of violet pedals and white ones in the second filial were very close to 3 to 1, which applied to the theoretic reasoning shown above.

He did many other experiments focusing on different types of genotypes of the pea plants and the results were shockingly similar. The hidden phenotype in the first filial reappeared in the second filial and the ratio of the dominant to the recessive phenotype were all close to 3 to 1.

The 3:1 ratio is referred to as the monohybrid ratio and is the basis for all patterns of inheritance in higher organisms.

One simple extension of the 3:1 phenotype ratio is a 1:1 ratio, produced when a heterozygous F1 individual is crossed to the homozygous-recessive parent. The process is known as testcross.

Testcross is useful in any condition when it is necessary to determine whether an individual is heterozygous or homozygous. Conceivable that if F2 all have dominant phenotype, then the tested parent is homozygous-dominant; if F2 have a 1:1 ratio of dominant and recessive phenotype, then the tested parent is heterozygous.

 

IIllustrations of wild animals [insect 3 Odonata]

Before this section, make sure you have read the page introducing classification of insects.(Illustrations of wild animals [insect 1])

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蜻蜓目 ODONATA

Odonata means “toothed jaws,” and indeed the larger species of dragonflies and damseflies may give you a startling but harmless bite.Despite what your mother told you about dragonflies sewing up your lips, they cannot stitch or sting you in any way.

The order Odonata is subdivided into three suborders: Anisoptera, the dragonflies; Zygoptera, the damselflies; and Anisozygoptera, mostly fossilized species with only two known living members.

  • physical features

extremely large eyes (in proportion to its head)

a long, slender abdomen

Large mandibles(jaw), chewing prey quickly and easily, an important feature since these insects tend to eat on the move.

Thorax tilted, positioning the legs just below the mandibles where they function as a prey-catching basket.

“Primitive winged,” ( wings that cannot be folded).  giving Odonates the interesting abilities to hover, fly backward, and take off vertically, similar to a helicopter.

Being able to rotate their heads nearly 360 degrees, giving them an almost limitless field of view.

Dragonflies and damselflies have tiny antennae, so vision is their primary means of navigating and capturing prey.

——————————————————————————-

Odonate eggs are laid in water, where they hatch into wingless naiads. The naiads have gills, and will molt up to 15 times, depending on the species. Some naiads remain in their aquatic environment for as long as two years before reaching adulthood. The final molt produces functioning wings, and the adult dragonfly or damselfly can hunt over water or land.

  • Habitat and Distribution:

Odonates inhabit every continent except Antarctica, in habitats where fresh water is present. Most species in the order are tropical.

  • Major Families and Superfamilies in the Order:
  1.  Aeshnidae – darners
  2. Gomphidae – clubtails
  3. Libellulidae – common skimmers and chasers
  4. Coenagrionidae – narrow-winged damselflies
  5. Corduliidae – emeralds

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↑Quoted from Order Odonata – Characteristics of Dragonflies and Damselflies By Debbie Hadley

>Learn more about Odonata 

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蜓科  Aeshnidae  (darners)
  1. 黑纹伟蜓 Anax nigrofasciatus
  1. 碧伟蜓 Anax parthenope
春蜓科  Gomphidae (clubtails)

1. 弗鲁戴春蜓 Davidius fruhstorferi

  1. 联纹小叶春蜓 Gomphidia confluens

4. 小团扇春蜓 Ictinogomphus rapax

蜻科  Libellulidae (common skimmers and chasers)

1.  六斑曲缘蜻 Palpopleura sexmaculata

  1. 半黄赤蜻Sympetrum croceolum

3. 夏赤蜻 Sympetrum darwinianum

4. 大黄赤蜻 Sympetrum uniforme

5. 小黄赤蜻Sympetrum kunckeli

6.竖眉赤蜻 Symprtrum eroticum ardens

7. 红蜻 Crocothemis servilia

9. 晓褐蜻 Trithemis aurora

蟌科 Coenagriidae  (narrow-winged damselflies)
  1.  截尾黄蟌 Ceriagrion erubescens

2. 矛斑蟌 Coenagrion lanceolatum

3. 杯斑小蟌 Agriocnemis femina

 

Review of Mendel’s Genetics

Here I found a great page story-telling  Mendel’s Genetics.Can’t be more suitable as a revision of what we learned about genetics and inheritance in high school.  >>Mendel’s Genetics

I believe by reading the link page you have remembered the principles of Mendel’s Genetics. We’ll  summarize these principles again in next posts.

While Mendel’s research was with plants, the basic underlying principles of heredity that he discovered also apply to people and other animals because the mechanisms of heredity are essentially the same for all complex life forms.”

It must be a cliche to summarize the success factors of Mendel’s experiments, but it has to be done, for many of the factors are still important for today’s experimentalists.

Firstly, before the experiment,Mendel spent a long time observing different traits of the peas and decided which traits he was going to focus on in the after experiments. He was prepared, had anticipation and, perhaps already held some hypothesis of what was going to happen.

Then it was the choice of his “lab-rats”. As the link page says,”Mendel picked common garden pea plants for the focus of his research because they can be grown easily in large numbers and their reproduction can be manipulated. ” Based on a large number of offspring, the resulting statistics can be assumed as very close to theoretic  statistics.  In this case, it’s  way more convenient to study the traits of these peas than those of some fragile and rare pole plants. 

More important, “pea plants have both male and female reproductive organs.  As a result, they can either self-pollinate themselves or cross-pollinate with another plant.  In his experiments, Mendel was able to selectively cross-pollinate purebred plants with particular traits and observe the outcome over many generations.  This was the basis for his conclusions about the nature of genetic inheritance.”

Reproductive
structures of
flowers

drawing of a flower cross-section showing both male and female sexual structures
the picture is from http://anthro.palomar.edu

Last but not least, Mendel was a pioneer in applying Math(Statistics) to experiment analysis. He rounded the ratio of numbers of different traits to a whole number and discovered the astonishing similarity of all the results.

In high school that’s all the factors, but actually there’s more. For one, Mendel succeeded because all the genes that controlled traits he picked to observe happened to be on different chromosomes. Otherwise, the  phenomena of “linkage” would have appeared (which we’ll talk about later)and he should never have had such a groundbreaking discovery.

What is molecular biology

Generally speaking, molecular biology is the study of structure and function of macromolecules such as nucleic acids, proteins and other polymers. In a narrow sense, molecular biology focuses on nucleic acids and their activities, such as transcription, translation, DNA replication, recombination, translocation and so on.

Writing in Nature in 1961, William Astbury described molecular biology as:

“…not so much a technique as an approach, an approach from the viewpoint of the so-called basic sciences with the leading idea of searching below the large-scale manifestations of classical biology for the corresponding molecular plan. It is concerned particularly with the forms of biological molecules and […] is predominantly three-dimensional and structural—which does not mean, however, that it is merely a refinement of morphology. It must at the same time inquire into genesis and function.”

Foundation of Molecular Biology:
  • —1869: Discovery of nucleic acids (nuclein) 
  •  —F. Miescher
  • —1944: Proofing of nucleic acids are genetic materials
  • —1953: Proposition of DNA structure – “double helix model”  (Watson and Crick, 1962 Nobel)
  • 1954: Establishment of “central dogma” (—Crick)
  • 1958: Mechanism of DNA replication (Meselson and Stahl)
  • —1961: “Operon” model of gene regulation (Jacob and Monod)
  • —1964: Identification of genetic codes (Nirenberg, 1968 Nobel)

Era of Genetic Engineering

  • —1970: Discovery of reverse transcriptase  (Temin and Baltimore, 1975 Nobel)
  • —1972: First recombinant DNA in vitro (—Berg, 1980 Nobel)
  • —1973: First transformation of hybrid plasmid into E. coli (—Cohen and Boyer)
  • 1977: First genetically modified product (Boyer, somatostatin )
  • 1977: DNA sequencing methods (Sanger and Gilbert, 1980 Nobel)
  • 1985: DNA in vitro amplification technology-PCR）
  • —1970: Discovery of reverse transcriptase (Temin and Baltimore, 1975 Nobel)
  • 1972: First recombinant DNA in vitro (—Berg, 1980 Nobel)
  • —1973: First transformation of hybrid plasmid into E. coli (—Cohen and Boyer)
  • —1977: First genetically modified product (Boyer, somatostatin)
  • —1977: DNA sequencing methods (—Sanger and Gilbert, 1980 Nobel）
  • —1985: DNA in vitro amplification technology-PCR（—Mullis, 1993 Nobel)
Era of Genomics and post-Genomics
  • —1986: Establishment of “Genomics” concept (Dulbecco, Roderick and McKusick)
  • —1990: Human genome project starts (—USA department of energy)
  • —2003: Completion of sequence mapping of human genome (—International HGP organization)
  • —2003-now: functional analysis of genome (post-genomics)

Genome Projects-Current Researches:

  • —Genetic engineering
  1. GMO (Genetically modified organism 基因修饰生物)
  2. —Cancer and gene therapy
  • —Regulation analysis of gene expression
          Signal transduction, TFs, RNA splicing, etc
  • —Structural and functional analysis of biological macromolecules
  1. —X-ray crystallography, NMR, EM etc
  2. —Yeast two-hybrid, immunoprecipitation etc
  • —Genomics, proteomics and bioinformatics
  • —…..

Hotspots