Differentiate between acquired traits and inherited traits, giving examples of each . • Identify Gregor a difference between the two lists. Introduce the concept of. I found this link from Scientific American Hip Hop Evolution Files: Heritable Traits vs. Inherited Traits that describes heredity as being traits you get from either a. Explain the relationship between traits and heredity. Traits are individual forms of characteristics in a population. Heredity is the passing of these traits from.
Theophrastus proposed that male flowers caused female flowers to ripen;  Hippocrates speculated that "seeds" were produced by various body parts and transmitted to offspring at the time of conception;  and Aristotle thought that male and female fluids mixed at conception.Acquired and Inherited Traits-Heredity and Evolution-CBSE Class 10 Science
The Doctrine of Epigenesis and the Doctrine of Preformation were two distinct views of the understanding of heredity. The Doctrine of Epigenesis, originated by Aristotleclaimed that an embryo continually develops.
The foundation of this doctrine was based on the theory of inheritance of acquired traits. The Preformationist view believed procreation was an act of revealing what had been created long before.
Genetics: The Study of Heredity
However, this was disputed by the creation of the cell theory in the 19th century, where the fundamental unit of life is the cell, and not some preformed parts of an organism. Various hereditary mechanisms, including blending inheritance were also envisaged without being properly tested or quantified, and were later disputed. Nevertheless, people were able to develop domestic breeds of animals as well as crops through artificial selection.
The inheritance of acquired traits also formed a part of early Lamarckian ideas on evolution. During the 18th century, Dutch microscopist Antonie van Leeuwenhoek — discovered "animalcules" in the sperm of humans and other animals.
These scientists formed a school of thought known as the "spermists". They contended the only contributions of the female to the next generation were the womb in which the homunculus grew, and prenatal influences of the womb. Ovists thought women carried eggs containing boy and girl children, and that the gender of the offspring was determined well before conception.
Heredity - Wikipedia
Modern synthesis 20th century The idea of particulate inheritance of genes can be attributed to the Moravian  monk Gregor Mendel who published his work on pea plants in However, his work was not widely known and was rediscovered in It was initially assumed that Mendelian inheritance only accounted for large qualitative differences, such as those seen by Mendel in his pea plants—and the idea of additive effect of quantitative genes was not realised until R. Fisher 's paper, " The Correlation Between Relatives on the Supposition of Mendelian Inheritance " Mendel's overall contribution gave scientists a useful overview that traits were inheritable.
His pea plant demonstration became the foundation of the study of Mendelian Traits. These traits can be traced on a single locus. History of genetics and History of evolutionary thought In the s, work by Fisher and others resulted in a combination of Mendelian and biometric schools into the modern evolutionary synthesis. The modern synthesis bridged the gap between experimental geneticists and naturalists; and between both and palaeontologists, stating that: Discontinuities amongst species or other taxa are explained as originating gradually through geographical separation and extinction not saltation.
Selection is overwhelmingly the main mechanism of change; even slight advantages are important when continued. The object of selection is the phenotype in its surrounding environment. The role of genetic drift is equivocal; though strongly supported initially by Dobzhanskyit was downgraded later as results from ecological genetics were obtained.
The primacy of population thinking: The strength of natural selection in the wild was greater than expected; the effect of ecological factors such as niche occupation and the significance of barriers to gene flow are all important.
The idea that speciation occurs after populations are reproductively isolated has been much debated. Thus sexual reproduction is the biggest contributor to genetic variation among individuals of a species. Twentieth-century scientists came to understand that combining the ideas of genetics and natural selection could lead to enormous strides in understanding the variety of organisms that inhabit our earth.
Mutation Historically, scientists have defined living creatures by the presence of DNA, but how living creatures process information may be a better hallmark of life, a new study argues Credit: NASA Scientists realized that the molecular makeup of genes must include a way for genetic information to be copied efficiently.
Genetics: The Study of Heredity
Each time cells divide to form new cells, this vast chemical library must be copied so that the daughter cells have the information required to function. Inevitably, each time the DNA is copied, there are minute changes. Most such changes are caught and repaired immediately.
However, if the alteration is not repaired the change may result in an altered protein. Altered proteins may not function normally. Genetic disorders are conditions that result when malfunctioning proteins adversely affect the organism. Images of DNA Structures ] In very rare cases the altered protein may function better than the original or result in a trait that confers a survival advantage. Such beneficial mutations are one source of genetic variation. Gene flow Another source of genetic variation is gene flow, the introduction of new alleles to a population.
Commonly, this is due to simple migration. New individuals of the same species enter a population. Environmental conditions in their previous home may have favored different forms of traits, for example, lighter colored fur.
Alleles for these traits would be different from the alleles present in the host population. When the newcomers interbreed with the host population, they introduce new forms of the genes responsible for traits.
Favorable alleles may spread through the population. Genetics by the Numbers — 10 Tantalizing Tales ] Genetic drift Genetic drift is a change in allele frequency that is random rather than being driven by selection pressures.
Remember from Mendel that alleles are sorted randomly into sex cells. It could just happen that both parents contribute the same allele for a given trait to all of their offspring. When the offspring reproduce they can only transmit the one form of the trait that they inherited from their parents. Genetic drift can cause large changes in a population in only a few generations especially if the population is very small. Genetic drift tends to reduce genetic variation in a population.
In a population without genetic diversity there is a greater chance that environmental change may decimate the population or drive it to extinction.