formation of new species Flashcards
what is a species ?
a species is a group of organisms that closely resemble each other and are able to breed among themselves but not with any other species
what is a population?
a group of individuals of the same species occupying a particular habitat
what causes variation in individuals in a species ?
A. sexual reproduction: through meiosis
during meiosis shuffling of genetic material occurs;
A.1.1)the random arrangements of homologous chromosomes on the equator and the crossing over of bivalent forms
A.2) Chance fertilization is when male and female gametes recombine and this results in a variety of genotypes for the offspring.
A.2.2) random mating
what causes variation in individuals in a species ?
what is gamete mutation ?
B) mutations- a mutation is a sudden alteration in genetic makeup of a organism
gamete mutations occur in the gametes can give rise to offspring that carry mutations in all its cells, these germline mutations can be passed on to offspring’s
what is polyploidy ?
it is when a whole chromosome is deleted or duplicated and the entire chromosomal compliment can multiply
what is the main source of of genetic variation?
it is when changes in base sequences occur and new alleles are created
give two examples of variations in populations
example one: the different beaks forms of the galapagos finches -they are pointed an blunt these differences allowed finches to occupy new niches available on islands and to feed on different types of food
example 2: the color of the white lions
the color of the white lions is caused by a recessive trait derived from a harmless mutation, this mutation does not affect their survival, they hunt and breed with other lions successfully and the white allele may not be expressed when mating with a normal lion it may be +expressed when two recessive allele appear
what are the effects of inbreeding in nature?
- it leads to a loss of genetic diversity which will prevent evolution
- it results in homozygosity which increases the chance of offspring’s being affected by a recessive disorder and decrease biological fitness of a population
what is inbreeding?
is mating of genetically close related individuals
what are the effects of inbreeding in animals?
they have a low birth weight and don’t reproduce successfully and are less resistant to dieases,predation and environmental stress
what are the effects of inbreeding in plants ?
the plants produce less seeds, germinate poor seeds and their stress resistance is less.
what the effects of inbreeding in humans ?
humans use inbreeding to establish desirable traits to continue a particular characteristic.
what is outbreeding ?
its the production of offspring from the breeding of two unrelated individuals
what does out breeding in nature lead to?
it leads to increased genetic variation which increases chances of evolution
it promotes heterozygosity decreasing chances of offspring being affected by a recessive gene
new desirable traits are introduced
what is inbreeding in humans?
it is the mating of close relatives like a mother and a son.
