Sunday, November 29, 2009

Zoology Homework Help | Zoology Assignment Help

Homework / Assignment Help in Zoology Upto College / Graduate Level

Zoology or Life Sciences is a broad classification that includes all sciences related to living organisms and their environment. As you delve deeper into the science of life, you would come across mysteries such as Molecular Evolution and Genetic Drift that have puzzled scientists for centuries. Homework Assignment Help in Zoology offered through e-mail, is the best way to find more about a particular concept in detail.


Bilogy Homework help and Bilogy Assignment Help

Homework Help and Assignment Help in Biology Upto College / Graduate Level

Biology or Life Sciences is a broad classification that includes all sciences related to living organisms and their environment. As you delve deeper into the science of life, you would come across mysteries such as Molecular Evolution and Genetic Drift that have puzzled scientists for centuries. Homework Assignment Help in Biology offered through e-mail, is the best way to find more about a particular concept in detail.

Homework Help in Biology is the best way to learn more about the given topic. It offers you crisp information in an easy-to-understand language and in a manner that is even easier to explain or present in a class. All you have to do is to send in an e-mail and you will get the help you need with your particular homework assignment or project, such as references to related works, a readymade report, solutions to your queries with diagrams and images included, and side remarks to help you understand the process of completing the assigned Biology homework.

Thursday, November 26, 2009

Chordata | Chordates | Phylum chordata | Chordata Examples

Chordata

  • Chordata name given by Balfour.
  • Herst put hemichordata into separate phylum.
  • Lamarck gave the word tunicata & vertebrata.
  • Pisces classified by Romer.
  • Amphibia classified by G.K. Noble.
  • There are 65,000 species of chordata.
  • Pisces is largest class, having 33,000 species.
  • Amphibia is smallest class having 2500 species.

CHARACTERS of chordata –

  • Total animals are 3–5% of animal kingdom.
  • Notochord or chorda dorsalis present in any stage of life cycle.
  • Gill slits present in any stage of life cycle.
  • Nervous system is dorsal, single & hollow.
  • Post anal tail present.
  • Mouth after first segment.
  • Anus before last segment.
  • Liver is present.
  • Heart is ventrally placed.
  • Flow of blood on dorsal side, anterior to posterior.
  • Flow of blood on ventral side, posterior to anteriror.
  • R.B.C. present.
  • Circulatory system closed.
  • Alimentary canal is placed ventral to nerve cord.
  • Symmetry bilateral.
  • Organ system grade.
  • Triploblastic animals.
  • True coelomate.
  • Enterocoelic.
  • Unisexual.
  • Sexual reproduction present.
  • Larvae generally absent.
  • Power of regeneration less.
  • Cold blooded / warm blooded.
  • Portal system present.


Chordata is divided into 2 parts –


1. Protochordata 2. Vertebrata


We cover the following Topics in Chordata:

Chordata is divided into 2 parts –

1. Protochordata 2. Vertebrata

S. No.

Character

Protochordata

Vertebrata

1

No to chord or chorda

dorsalis

Present in original

form

Converted into

vertebral column & cranium

2

Habital

Marine

All habitas

3

Feeding

Cilliary

Maybe

4

Evolution

Early

Late

5

Size

Small

Large

6

Endostyle

Present

Thyroid gland

present

Non Chordates | Non Chordata | Non Chordate animals

Non – Chordata

Animals are studied in the branch Zoology. Father of Biology, Zoology & Embryology is Aristotle. There are 12,00000 species of animals present in world. Every year new 10,000 species of animals are added. These animals show different habit & habitats. Some are ­– Free living, Commensal, Symbiotic, Parasitic, Predators. Some common habitats are –

Terestrial – On land Fossorial – Burrowing

Scansorial – Climb on wall. Fresh water – In normal water

Marine – In Sea Benthic – Attached to bottom.

Pelagic – On surface Lentic – In running water

Lotic – In standing water Arboreal – On trees Aerial – Flying Oceanic or Abysal– In deep sea

Littoral – In intertidal zone

Planktonic – Inactively floating on surface

Nektonic – Actively floating on surface

Scientist divided animals in to groups or categories on the basis of similarties and dissimilarities of characters. It are known as classification.So in classification groups are formed. These groups are texa (singular – texon). Texon word was given by Meyer. These texa are – Kingdom – Phylum – Class – Order – Family – Genus – Species. Few words as supra, sub & infra are used to increase number of texa.

Largest taxon is Kingdom. Smallest taxon is Species. Unit of classification is species. Classification is studied in taxonomy. Taxonomy word given by De Candelle. Taxonomy includes identification, nomenclature & classification of individual.

We cover the following Topics in Non Chordates:

Thursday, November 19, 2009

Sample Homework Physics | Physics Homework Assignment Help

Please go through the following links for the sample homework done by our expert physics tutors:



  • Gas laws

  • Lattice parameter

  • Vacancy concentration

  • Activation energy

  • Atomic fraction

  • D Block elements Homework Assignment Help | Chemistry Homework Help

    A transition element may be defined as an element whose atom in the ground state or ion in common oxidation state has incomplete sub-shell, has electron 1 to 9. It is called transition element due to fact that it is lying between most electropositive (s-block) and most electronegative (p-block) elements and represent a transition from them. The general electronic configuration of these element is (n–1)1 to 10 ns 0 to 2

    The definition of transition metal excludes Zn, Cd and Hg because they have complete d- orbital. Their common oxidation state is Zn++, Cd++, Hg++ They also do not show the characteristics of transition element. Element of group 3 (Sc, Y, La and Ac) and group 12 (Zn, Cd, Hg) are called non typical transition element.


    Please go through the following links for more info:

    Hydrogen and its properties | Hydrogen homework assignment help

    Hydrogen


    (1) Position of hydrogen in the periodic table


    Hydrogen is the first element in the periodic table. Hydrogen is placed in no specific group due to its property of giving electron (When H– is formed) and also losing electron (When H+ is formed).


    (i) Hydrogen is placed in group I(Alkali metals) as,


    (a) It has one electron in its (Outer) shell-1s1 like other alkali metals which have (inert gas) ns1 configuration.


    (b) It forms monovalent H+ ion like Li+, Na+ ..........


    (c) Its valency is also 1.


    (d) Its oxide (H2O) is stable as Li2O, Na2O.


    (e) It is a good reducing agent (In atomic as well as molecular state) like Na, Li ............


    (ii) Hydrogen also resembles halogens (Group VII A) as,


    (a) It is also diatomic (H2) like F2, Cl2 ...........


    (b) It also forms anion H– like F–, Cl– by gain of one electron.


    (c) H– has stable inert gas (He) configuration as CH4, C2H6 like halogens CCl4, SF2Cl2 etc.


    (d) H is one electron short of duplet (Stable configuration) like F, Cl which are also one electron deficient than octet, F – 2s22p5; Cl – 3s23p5.


    (e) (IE) of H(1312 kJ mol–1) is of the same order as that of halogens.


    (iii) (IE) of H is very high in comparison with alkali metals. Also size of H+ is very small compared to that of alkali metal ion. H forms stable hydride only with strongly electropositive metals due to smaller value of its electron affinity (72.8 kJ mol–1).


    (iv) In view of the anomalous behaviour of hydrogen, it is difficult to assign any definite position to it in the periodic table. Hence it is customary to place it in group I (Along with alkali metals) as well as in group VII (Along with halogens).