Natality rate - natality, Biology

Assignment Help:

Natality Rate - Natality

Natality rate or birth rate is determined by dividing the number of individuals born by unit time and is expressed as follows:

Natality rate =  ΔNn / Δt

Δ Nn = production of new individuals in a population

Δ t = unit time

Natality rate can also be determined as the number of new individuals per unit of time per unit of population. This is called specific natality rate and can be expressed as:

Natality rate per unit of population = ΔNn / N Δ t

N may represent the total population or only the reproductive part of the population, i.e. females, for example, in higher organisms natality rate is per female. Natality rate is zero or positive but never negative. The measurement of natality or birth rate is highly dependent on the type of organism being studied. Some species breed once a year, some breed several times a year and others breed continuously. Some produce many seeds or eggs, and others few.

For example, a single oyster can produce 55 to 114 million eggs, whereas birds usually lay between 1 and 20 eggs. Also the specific natality rate differs for individuals of different age groups in the population. For example in a rabbit population for 1 to 2 year old females the specific natality rate is average 4 young ones per year per female, while for females of less than 1 year the rate is 1.5 on an average. Since natality is the concept referring to the population and not to the isolated individuals, the average reproductive capacity should be taken as the measure of natality, and not the capacity of the most productive or least productive individuals.

 


Related Discussions:- Natality rate - natality

Peptide bond, PEPTID E BOND Peptide or amide bond is a linkage es...

PEPTID E BOND Peptide or amide bond is a linkage established condensation reaction between amino group of one amino acid and carboxylic group of the second amino acid.

Structure of the stomach, Describe the structure of the stomach. How is it ...

Describe the structure of the stomach. How is it modified to carry out its functions? How does it compare to that of the fetal pig?

Explain the mechanism of temperature regulation, Any significant variation ...

Any significant variation in the internal temperature could have damaging effects on the body's enzymes. Homeotherms or warm-blooded animals including human can however generate co

Chromosomes and chromatin strands are present in stage, Drosophila has 4 bi...

Drosophila has 4 bivalents (homologous chromosomes) formed at Meiosis I. How many chromosomes and chromatin strands are present in each of the following stages- Anaphase of mito

Community gradients and boundaries, Community Gradients and Boundaries ...

Community Gradients and Boundaries It is often difficult or impossible to determine where one community ends and the next begins. Many communities, in fact, grade continuousl

Define about the gastric cancer, Define about the Gastric Cancer? Surgi...

Define about the Gastric Cancer? Surgical treatment is a very common mode of treatment in gastric cancer. Radiation and/or chemotherapy are given for patients with resected but

Rna molecule have two polynucleotide chains like the dna, Q Does RNA molecu...

Q Does RNA molecule have two polynucleotide chains like the DNA? Only DNA has two polynucleotide chains. The RNA is formed by just one polynucleotide chain.

Nekton - aquatic ecosystem, Nekton - Aquatic Ecosystem This group cont...

Nekton - Aquatic Ecosystem This group contains animals which are swimmers. The nektons are relatively large and powerful as they have to overcome the water currents. The anima

Protozoa, Characteristics Protozoa and examples

Characteristics Protozoa and examples

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd