Natural Selection.
An easy and important way to remember this is by thinking of a species - let’s say a bright white moth. For ages, these moths have survived beautifully, matching perfectly with the white tree bark they live on, until one day, a smoky building begins pumping its soot into the air. This air begins to change the color of the tree bark to black and the once hidden white moths are now plainly visible to birds who eat them easily. Fortunately, every now and then a moth is born who is darker than the rest - black as soot even. And so, the birds keep eating the white moths but missing the soot-colored ones. As time goes by, the soot-colored moths produce more and more similarly colored moths, who are well hidden from the birds AND after enough time, the only moths that remain are soot-colored. This is why so many species “fit” exquisitely into their environment. They have ALL adapted in some way similar to the soot-colored moth.
Answer: 75% of the plants are purple and 25% are white. The phenotypic ratio can be expressed as 3:1.
Explanation:
Heterozygous means that its genotype has two distinct alleles, i.e. a dominant and a recessive one. So the genotype of the plants is Pp, and each plant has two alleles since<u> they are diploid organisms, which have two copies of each gene.
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<u>Each plant produces gametes, which are haploids cells. That is, they only have one copy of each gene (one allele)</u>. So, the gametes produced by Pp have a P or p genotype. During fertilization, the maternal and paternal gamete are fused to form a diploid zygote where their genotype will have one allele from the father and one from the mother.
By making this monohybrid cross, we cross the gametes of each parent in the punnett square (see picture)
In the offspring, we see one PP genotype (homozygous dominant), two Pp genotypes (heterozygous) and one pp genotype (homozygous recessive). <u>Since we know the P allele is dominant and it codes for purple color, a genotype only needs one P allele to express that phenotype</u>. So Pp and PP organisms are purple, and only pp is white. That means 75% of the plants are purple and 25% are white. The phenotypic ratio can be expressed as 3:1.
Fixed action patterns are <span>behaviors that follow a fixed, unvarying pattern and are used in accordance to studying animals and their behaviors to both the environment and each other. </span>