Genetic Change and Traits
What is a gene?
A gene is a specific segment of DNA that provides instructions for an inherited trait.
What is the name of the process by which a population's environment determines which traits are beneficial and which are not?
Natural selection
What is extinction and name three types of extinctions we discussed
Extinction occurs when there are no members of a species left on Earth.
Background Extinction
Mass Extinction
Human Activity
True or False?
Geographic barriers can result in speciation.
True.
True or False?
Background extinctions happen at a fairly constant rate as species fail to adapt or compete in their environments while others succeed
True
Traits that help organisms survive and reproduce in their current environment is called what?
Adaptations
What is genetic variation?
What is it called when two or more populations of the same species no longer reproduce due to a barrier in reproduction.
Speciation
What is the different between mass extinction and background extinction?
Background extinction is when a species fails to adapt or compete in their environment while others succeed
Mass extinction is caused by environmental changes such as asteroid collisions, sea level changes, volcanic eruptions
A group of individuals that can reproduce successfully in nature
Species
If a mutagen changes the genetic structure of a skin cell after birth, which of the following could not occur and why?
A.The cell replicates, passing the mutation on to many cells in the body.
B. The cell stops functioning because of the mutation and eventually dies.
C. The cell produces a new protein because of the mutation, resulting in a new trait.
D. The cell passes the mutation on to the skin cells of offspring born after the mutation.
D could not occur because the mutation happens in the skin cell which is not a reproductive cell, therefore cannot be passed on
House sparrows were introduced to the cold climates of North America in 1852. Since that time, the bodies of sparrows in the north became larger than those of southern sparrows. What is the most likely cause of the change in northern sparrow body size?
A. If cold weather increases the rate of mutations in the genome, sparrows can mutate into larger organisms.
B. If larger sparrows cannot breed with smaller sparrows, they become isolated and form a new species.
C. If smaller sparrows cannot survive as well in cold weather, only sparrows with genes for large bodies will survive.
D. If sparrows shiver in the cold and gain muscle mass from the shivering, their body size will increase.
C.
More fit individuals survive to pass down their genes
True or False?
Members of the same species are always identical
False
having a different appearance is not necessarily an indication of being a different species.
The sequence of DNA is responsible for determining the sequence of 1. __________ in proteins. When this sequence is changed, the shape of the protein is affected. Since the shape of the protein determines the 2. __________ of the protein, mutations in DNA can cause disease.
1. Amino acids
2. Function
Define genetic variation
refers to different types of genes in a population for an inherited charatceristic
DNA provides the template for producing proteins. Which of these models shows how genetic information produces traits in an organism?
A.
DNA produces proteins, and amino acids are coded in triplets
A species of butterfly has several genes that regulate the green wing color of the animal, and mutant individuals can have white or black wings. The graph shows the distribution of wing colors in this population.
How would this distribution change if a predator that specifically targets green butterflies entered the ecosystem?
D.
The population would diversify away from green butterflies.
Describe at least two factors that can lead to speciation
Geographic barriers, food resources, differences in mating behaviors
Explain how genetic variation and the environment influence the distribution of traits
The environment determines which traits are advantageous and can affect the distribution of a trait to change over time.
What is the change in the inherited traits of a population over many generations?
Evolution
If a nucleotide is removed from a gene, the order of nucleotides will shift, resulting in new 1. __________ being coded for. These will combine to form a different 2. __________
1. amino acid
2. protein
A population of trees shows variation in the size of the fruit produced. Some trees produce large fruits and some trees produce small fruits. Which of the factors would result in an increase in the frequency of the large-fruit trait and which would result in an increase in the frequency of the small-fruit trait?
A. An unusually cold spring kills many of the trees that produce large fruits.
B. A drought kills birds that eat and disperse the seeds of the large fruits.
C. A fungal disease attacks the population but cannot target seeds that are surrounded by thick layers of fruit.
D. A newly introduced pollinator prefers the flowers of trees that produce small fruits.
Large Fruit:
C
Small Fruit:
A, B, D
Over Earth’s history, mass extinctions in which large numbers of species became extinct have occurred multiple times.
Identify two factors that can contribute to a mass-extinction event and explain why some organisms are able to survive an event that causes mass extinction.
Asteroid collisions, sea level changes, volcanic eruptions etc.
The populations that survive a mass-extinction event must have traits that help them survive and reproduce in the new environment. Populations can begin to exploit previously occupied niches, which can lead to reproductive isolation
Describe how genes, chromosomes, proteins, mutations, and mutagens are related to each other.
Chromosomes contain sections called genes, which code for proteins. Mutagens are substances that can cause mutations in the genes, resulting in new proteins.
A change in the base-pair sequence of a gene is called...
Mutation