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

Three phases into which the cell respiration is divided, What are the three...

What are the three phases into which the cell respiration is divided? The three phases of aerobic cell respiration are glycolysis, Krebs cycle and respiratory chain (also calle

How are the male gametophytes, How are the male gametophytes and the male g...

How are the male gametophytes and the male gametes formed in angiosperms? In the anthers of every stamen there are pollen sacs. Within the pollen sacs there are microspore moth

Adaptation and learning function of consciousness, Q. Adaptation and learni...

Q. Adaptation and learning function of Consciousness? Adaptation and learning function: Adaptation to novel experiences requires more conscious involvement, for successful lear

Reproductive system of asteroidea, Reproductive System of Asteroidea S...

Reproductive System of Asteroidea Sexes are separate in several asteroids. There are ten (10) gonads, two in each arm. They emerge tuft-like or as cluster of grapes. Mature go

Explain periimplant marginal tissues of mucosal conditions, Explain Periimp...

Explain Periimplant Marginal Tissues of Mucosal Conditions In addition to the redness and swelling of the marginal tissues, bleeding on probing (BOP), pocket formation, and sup

What are the cell kinds that form the phloem, What are the cell kinds that ...

What are the cell kinds that form the phloem? What are the major features of those cells? The major cells that form the phloem are the sieve elements and the companion cells an

What are the kinds of reproduction that occur in fungi, Q What are the kind...

Q What are the kinds of reproduction that occur in fungi? In fungi there is sexual and asexual reproduction. Fungi reproduce asexually by fragmentation, sporulation and gemmati

What is the chemical nature of carbohydrates, What is the chemical nature o...

What is the chemical nature of carbohydrates? The name carbohydrate owes its origin to the fact that most substances of this class have empirical formulae suggesting that they

Scientific american article suggests some improvement, The human skeleton h...

The human skeleton has evolved from that of four-legged animals. Unfortunately, the adaptation is far from perfect; thus, our upright posture causes problems like back age and the

What is physical activity ratio, What is Physical activity ratio? Physi...

What is Physical activity ratio? Physical activity ratio (PAR): The energy cost of an activity per unit of time (usually a minute or an hour) expressed as a multiple of BMR. It

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