Evolution??

Question

what could scientifically cause a biologcal entity to produce offspring with different traits other than what it could produce?

(dont say it was the enviornment thats not very explanitory

Answer 1

Genetic mutations. Even you, along with every other human, have 120-odd mutations in your genome that aren't expressed in your mother or father's DNA. Most mutations are neutral, of course, some are deleterious, but some are positive - there are some human population groups who are more resistant to coronary artery disease, or have denser bones, or resistance to HIV, or can see near-ultraviolet light, and many of these have been traced back to a mutation in a fairly recent common ancestor (a few hundred years back).

Answer 2

Two things: Mutations and sexual recombination with another individual.

Mutations are just errors in cell replication.   Every time a cell divides, it is copying millions to billions of letters (base pairs in the DNA).   All sorts of errors can occur during this process ... most are fixed by various processes, but a few errors remain and are passed on to subsequent cells.   In a single-celled organism this means that the offspring is different from the parent.   In a multi-cellular organism that uses sexual reproduction, the mutations would be the ones that occur during production of the s*x cells (sperm or egg cells), which would again affect the offspring.

Sexual recombination is the combining of one individuals genetic code with that of another.   The result can be a brand new combination of genes that is unlike either parent, and unlike any other individual of the species.

P.S. You are right that environment does not cause different offspring.   The environment affects whether that offspring has a better or a worse chance of survival than other individuals.   If the new genetics of the offspring give it some advantage in that environment, then that new set of genes will get reproduced into more offspring, and over time spread into the population.  

Answer 3

mutation

Answer 4

Every time a cell divides, it picks up random mutations in its DNA.  The DNA polymerase that replicates chromosomes prior to cell division is a good enzyme, but is not perfect.  This built in mutation rate ensures that each of the hundred million or so sperm in an ejaculation are all a little bit different.  Same thing for the eggs produced by the female.  Since the mutations are random, some might be good, some might be bad, and most are silent (neutral).

Once the organism is born, the environments then exerts selective pressures on the offspring.