Unit 7 Lesson 3: Heredity and Reproductive Success Flashcards
natural selection
a process in which individuals that are better adapted to a certain environmnet survive better and reproduce more offsprnig
To analyze differences in populations, geneticists often study different alleles. What is an allele
An allele is a variation in the form of a gene.
Where are genes and alles found
Every gene, and its alleles, are found on a specific part of each chromosome.
Every gene, and its alleles, are found on a specific part of each chromosome.
The gene for eye color, for example, is found in the same place on every chromosome of every individual in a species.
The gene for eye color, for example, is found in the same place on every chromosome of every individual in a species. Where do alleles come in
For instance, whether people have brown eyes or green depends on the alleles they inherited from their parents, but no matter what color their eyes, that allele will be in the same place on the same chromosome in every person.
The place that allele is found is called its
locus
locus
the location on the chromosome at which a gene or sequence of DNA is found
Every strand of DNA is made up of four nucleotides:
adenine, thymine, guanine, and cytosine.
In every species, each nucleotide appears in a specific location on the DNA strand, in a specific order. If there is a change in one of the nucleotides, this is called a
SNP, or single nucleotide polymorphism (the abbreviation “SNP” is pronounced like “snip”).
single nucleotide polymorphism (SNP)
a mutation that only changes a single base in a sequence of DNA
When a scientist looks at a specific locus for a red panda, a T nucleotide appears in most individuals, so a T nucleotide is what a scientist expects to see. In an SNP, the nucleotide may be an A, a C, or a G. What does this SNP allow scienstists to do
That change is a mutation, and if this mutation is passed on to the individual’s offspring, these SNPs allow scientists to track the evolutionary relationships between different populations of the same species.
What do SNPs allow sciesntis to do
This allows scientists to track how populations are related to one another without having to rely on mutations that change the phenotype of the individual.
haplotype mapping
a process by which the inheritance of a group of SNPs is used to establish ancestry or genealogy of a particular individual
How is haplotype mapping used
This is known as haplotype mapping, and it is commonly used in DNA tests designed to establish the ancestry of individuals.
Even if these SNPs do not change the overall appearance of the individual, the inheritance of specific SNPs can tell scientists to which population that individual is related. This is known as
haplotype mapping
data analysis
the process of observing, recording, and modeling data in order to discover useful information
dependent variable
a variable (represented on the y-axis of a graph) whose value is measured after changing the independent variable
independent variable
a variable (represented on the x-axis of a graph) whose value is changed by the researcher in order to see its relationship to a dependent variable
graph
a diagram that shows the relationship between two variables
Group behavior in lions
As an example, lions tend to live in groups called prides, which consist mostly of related female lions. Males and females are born at an equal rate, but males are cast out when they reach reproductive age. These males are often forced to hunt alone, with a success rate of 17 to 19 percent. In contrast, the lion prides have a successful hunt rate of 25 to 30 percent. Female lions provide communal care, nursing one another’s young and hunting together. Male lions will fight one another for access to mating rights and territory. These differences can lead to female lions living 50 percent longer than male lions.
Group behavior in meerkats
Another example is meerkats (Suricata suricatta). Meerkat families can consist of anywhere from three to 50 or more individuals and can be one family or multiple families combined into a “mob” or clan. One dominant female and male pair leads the group, birthing three litters per year; only one in six or seven female meerkats is ever reproductively successful, but all females lactate. These females will nurse and guard the dominant female’s young and will give away up to 40 percent of the food they find (such as scorpions, beetles, lizards, and fruit). The more babysitters there are, the higher the survival rate of the pups. This may not seem advantageous for subordinate females, but they are often related in some way to the dominant female, so their cooperation is still beneficial in passing on their genes. Meerkats also watch out for one another when foraging and hunting, calling out when they see predators. This behavior helps all individuals to survive.
Natural selection leads to change over time. An individual inherits an adaptation from its parents . Once the individual is developing, its traits are fixed. DNA tells an organism’s cells what to do, and how and when to do it, and what that organism can do is limited by its DNA. A frog, for instance, can’t suddenly grow fur in the egg just because the weather is cold.
But now, scientists are discovering that individuals may inherit more than genetic blueprints from their parents. They may also inherit options. Give an example
When red-eyed tree frog eggs detect vibration, they can hatch up to two days early. An early hatch gives eggs that would otherwise be eaten at least some chance to survive.
Group behavior can significantly increase an individual’s chances of
Group behavior can significantly increase an individual’s chances of reproduction and survival, therefore increasing a species’ success.
what are example of group behavior in animals
Group behavior includes actions such as hunting together, grooming one another, protecting territory and young, and caring for relatives and offspring.
