What are Darwin's principle's of natural selection?

Answer 1

The principles of natural selection are:

That life reproduces with variation.

That variant features are inherited by offspring.

That organisms always produce more offspring than can comfortably be sustained by the environment they inhabit.

That variant offspring therefore must compete for resources and mating opportunities.

That this competition results in the differential reproductive success of variants, and therefore in changing frequencies of variant traits in the population.

Answer 2

I. common descent with modification II. natural selection

or

1. The phenotype is different from the genotype

2. Acquired characteristics are not inherited

3. Genes retain their identity through generations, they do not blend

4. Genes mutate to stable alternative forms (alleles)

5. Evolutionary change is a Populational process

6. Natural Selection and random genetic drift can operate simultaneously. Changing genotype proportions in a population.

7. Natural selection can account for both slight and great differences among a species, as well as new traits that will subsequently evolve.

8. Natural selection can alter populations beyond original range of variation- giving rise to new phenotypes.

9. Mutations can accumulate in a population resulting in genetic variation that can evolve rapidly when environmental conditions change.

10. Founder Effect: Populations of a species in different geographic regions differ in characteristics that have a genetic basis.

11. Difference between sample sizes and even different populations of the same species evolve by small, incremental steps.

12. Reproductive Isolation: A species represents a distinct "gene poop"; groups of interbreeding or potentially interbreeding individuals that do not exchange genes with other such groups.

13. Speciation is the origin of two of more species from a single common ancestor.

14. Higher taxa arise by the prolonged, accumulation of small sequential differences, rather than sudden mutational origin of new "types."

15. All forms of life appear to have descended from a single common ancestor in the remote past.

16. the principles that explain evolution of populations and species may be extrapolated to the evolution of higher taxa (e.g. classes, phyla, kingdoms).

　

Answer 3

The elements of Natural Selection:

1. All populations have genetic variation.

2. The environment presents challenges to successful reproduction. (fitness / survival).

3. Individuals that are better able to cope with the challenges presented by their environment tend to leave more offspring than those individuals less suited to the environment (Inheritable characteristics).

4. Individuals tend to produce more offspring than the environment can support. (over-population / competition).

From those observations, two inferences can be made:

1. Individuals with inherited characteristics that increase their probability of survival and reproduction will have more offspring.
2. Favourable traits accumulate in the population as individuals have an unequal ability to reproduce.

Answer 4

The basic pricipals of evolution are;

1) Difference - Populations of organisms contain individuals with different traits.

2)Over population - Each generation produces more than the number of off-spring required to replace the existing generation.

3)Competition - Organisms will compete for resources (food, space, mates) and the ones with traits that make them most able to take possesion of those resources will breed more than the ones which lack these traits.

Neo-Darwinism adds

3) Genetics - Genes make organisms more able to compete for resources and the most beneficial genes will stand a greater chance of being passed on to the next generation.

4)Mutation - Rarley an individual will have a totally new trait caused by a genetic mutaion which is beneficial to the organism. This individual will be very sucessful in reproducing and so will its offspring who carry the gene. Over the course of many generations the number of individuals carrying the gene will increase.

Worked example;

There once was a population of horse like creatures living in an area with tall trees and very little grass.

1) Difference - Some of the horse like creatures(hlc's) were taller than others.

2) Over population - The hlc's had many babies some would survive and breed some would not.

3) Competition - there was not enough food for all the hlc's. The short hlc's could not reach as many leaves as the tall hlc's and so some of them starved to death and others were unable to nurse their babies, some of them managed to get by. The tall hlc's were better fed and could have more babies. The next generation had more taller hlc's than the first. The generation after had even more taller hlc's and this carried on for many generations. Eventually the hlc's looked a lot like giraffes.

4)Genetics - the genes which made the hlc's taller were more likely to be passed on to the next generation, over time some of the short genes were lost from the population others remained but very few hlc's had them.

5) Mutation - One individual had a mutant gene which caused the bones in his neck to grow longer than normal. This ment he was very well fed and got many mates. Some of his babies also had long necks and were also well fed, they had many babies too. Eventually, the hlc's with the normal short neck gene were out numbered by those with the long neck gene and after more generations there were no short necked hlc's at all (but perhaps the gene remains in the population with a very few individuals).

Answer 5

1. Organisms share a common ancestor.

2. Populations change over time through two mechanisms: natural selection and genetic drift

-Natural selection states that those organisms with characteristics that help it to survive will be more likely to reproduce and pass on those "favorable" characteristics to their offspring.

-Genetic drift is the random change in the genetic composition of a population due to chance events causing unequal participation of individuals in producing succeeding generations.

3. Eventually these changes will cause new species to develop, and is the reason for the diversification of today's organisms.

Answer 6

The four elements of Natural Selection are;

1. all populations have genetic variation.

2. the The_four_principles_of_natural_selectionpresents challenges to successful reproduction.

3. individuals that are better able to cope with the challenges presented by their environment tend to leave more offspring than those individuals less suited to the environment.

4. individuals tend to produce more offspring than the environment can support.

Answer 7

1. Variation is the raw material of natural selection

2. Living things face a constant struggle for survival(produce more offspring than survive)

3. Only some individuals survive long enough to reproduce

4. Natural selection results in genetic change

5. Species adapt to their environment (NS makes a species better suited to live in their environment)

Answer 8

- all individuals in a population are capable of reproduction.

- the populations sizes stays stable

- there are limited resources in the enviornment

- varriation is present

- varriation is inheritable

Answer 9

He said that a species will adapt to it's environment over time. Some people think that that means the "survival of the fittest" but is means that the ones in the group that can adapt better will produce more offspring that can also adapt better.

Answer 10

Organisms that have traits best suited to their environment are more likely to survive and reproduce.