How Changes in Population Lead to the Formation of

Name: How Changes in Population Lead to the Formation of
Brand: Academic Documents Platform
Price: 0.5 USD
Availability: InStock
Author: Daniel Miller

Natural selection worksheet illustrating directional, disruptive, and stabilizing selection through body‐size vs. population graphs. Includes questions on comparing variables and identifying selection types from the models.

Daniel Miller

Contributor

4.1

25 days ago

Preview (3 of 7)

Selection and Speciation
How can changes in a population result in the formation of a new species?
Why?J
Have vou ever wondered how the great diversity of life on Earth has come about or how a single new
species forms? Environmental pressures may cause populations to change overtime or evolve. This is
because an organism's abilitv to live to adulthood in its current environment will determine its
reproductive success and abilitv to pass on its genes. But changes withm a population can occur without
creating a new species. At what point do scientists start thinking of a new name for a species?
Model 1 - Three Types of Selection
DirccuMid Sdcuion Diirupuvt SefcciMMi
S a i i h E i r iri I faiL-* l i l u d *
i M i - hi i,.’ 1 - 5 ■ - - ;■ i : <, n | r »
& M W
1. What variables do die graphs in Model 1 com]
Bodr sise and number of people.
2. What are die three types of selection illustrated in the graphs in Model 1?
Directional., disruptive. and intermediate.
Selection and Speciation
How can changes in a population result in the formation of a new species?
Why?J
Have vou ever wondered how the great diversity of life on Earth has come about or how a single new
species forms? Environmental pressures may cause populations to change overtime or evolve. This is
because an organism's abilitv to live to adulthood in its current environment will determine its
reproductive success and abilitv to pass on its genes. But changes withm a population can occur without
creating a new species. At what point do scientists start thinking of a new name for a species?
Model 1 - Three Types of Selection
DirccuMid Sdcuion Diirupuvt SefcciMMi
S a i i h E i r iri I faiL-* l i l u d *
i M i - hi i,.’ 1 - 5 ■ - - ;■ i : <, n | r »
& M W
1. What variables do die graphs in Model 1 com]
Bodr sise and number of people.
2. What are die three types of selection illustrated in the graphs in Model 1?
Directional., disruptive. and intermediate.

3. According to the graphs in Model 1, there is variation in the bodv mass in the original
i. describe how this variation is possible.vour
Different alleles can occur within a population because of mutations.
4. Refer to graph A of Model 1.
j. H o w is the population that has experienced selection different from the original population?
The individuals in the new population have a larger bodv size then the individuals in the original
population.
A Fitness is defined as the relative ability of anindividual for population} to survive, reproduce,
and pass on genes. Which individuals in the original population appear to display better
fitness?
Those with a larger bodv mass because the species has evolved to favor it.
t. As a group, propose some characteristics of theenvironment that could lead to the population
changes illustrated in graph A.
The climate could become colder so those with more bodv mass could keep warmer.
5. Refer to graph E of Model la. H o w is the population that has experienced selection different
from tite original population?
i Which individuals in the original population appear to displav better fitness?
Thev are different because the individuals of the new p opulation are either larger or smaller than
the individuals o f the old population because o f disruptive selection.
t. As a group, propose some characteristics of theenvironment that could lead to the population
changes illustrated in graph B.
The environment could select against people with the middle bodv size since thev probablv are
not useful to the environment.
6. Refer to graph C of Model 1.
j. H o w is the ion that has ex- selection different from the origi
Those with the middle bodv mass are more ideal.
h. Which individuals in the original population appear to displav better fitness?
The middle bodv mass. f og:
3. According to the graphs in Model 1, there is variation in the bodv mass in the original
i. describe how this variation is possible.vour
Different alleles can occur within a population because of mutations.
4. Refer to graph A of Model 1.
j. H o w is the population that has experienced selection different from the original population?
The individuals in the new population have a larger bodv size then the individuals in the original
population.
A Fitness is defined as the relative ability of anindividual for population} to survive, reproduce,
and pass on genes. Which individuals in the original population appear to display better
fitness?
Those with a larger bodv mass because the species has evolved to favor it.
t. As a group, propose some characteristics of theenvironment that could lead to the population
changes illustrated in graph A.
The climate could become colder so those with more bodv mass could keep warmer.
5. Refer to graph E of Model la. H o w is the population that has experienced selection different
from tite original population?
i Which individuals in the original population appear to displav better fitness?
Thev are different because the individuals of the new p opulation are either larger or smaller than
the individuals o f the old population because o f disruptive selection.
t. As a group, propose some characteristics of theenvironment that could lead to the population
changes illustrated in graph B.
The environment could select against people with the middle bodv size since thev probablv are
not useful to the environment.
6. Refer to graph C of Model 1.
j. H o w is the ion that has ex- selection different from the origi
Those with the middle bodv mass are more ideal.
h. Which individuals in the original population appear to displav better fitness?
The middle bodv mass. f og:

b. Human babies with very high or very low birth weights have a higher mortality rate.
Babies with an intermediate weight will be selected for (stabilizing;.
c A population of seed-cracker finches feeds on seedsavailable in two sizes, small or
large.
Finches with either large or small beaks will be selected for. Disruptive;
d. Overfishing occurs in two rivers in British Columbia, Canada, where larger salmon ate
preferentially caught
Smaller fish will be selected for since the bigger fish are caught and killed. Directional;
c. As a group, propose some characteristics o f theenvironment that could lead to the population
changes illustrated m graph C.
Small amounts of food could be available and the environment could be changing.
As a group, define the following terms in grammatically correct sentences. Each definition should
contain the following words: population, selection, fitness, and environment.
j. Directional selection
One extreme of a phenotype is selected for compared to the middle and other extreme because
of the environmental conditions. This means that the population is most likely going to mainly
consist of the extreme because it has more fitness.
& Disruptive selection
Both extremes of a phenotype are selected for compared to the middle because of the
environmental conditions. This means that the population is most likely going to mainly
consist of the extremes because they have more fitness.
f. Stabilizing selection
The intermediate of a phenotype is selected for compared to the extremes because of the
environmental conditions. This means that the population is most likely going to mainly
consist of the intermediate type because it has more fitness.
8. In each of the following examples, describe the likely outcome due to the environmental pressure
and state the type of selection. Justify your choice.
j. Finches with a small beak cannot crack open seeds.
A population with a larger beak will be selected for because die smaller beak cannot get
food.(Directional',
A Human babies with yen' high or very low birth weights have a higher mortality rate.
Babies with an intermediate weight will be selected for (stabilizing).
y. A population of seed-cracker finches feeds o n seedsavailable in two sizes, small or
large.
Finches with either large or small beaks will b e selected for. Disruptive j
d. Overfishing occurs in two nvers in British Columbia, Canada, where larger salmon are
preferentially caught
Smaller fish will be selected for since the bigger fish are caught and killed. (Directional)

Preview Mode

100%

Study Now!

XY-Copilot AI

Unlimited Access

Secure Payment

Instant Access

24/7 Support

Document Chat

Document Details

Subject

Biology

How Changes in Population Lead to the Formation of

Study Now!

Document Details

Related Documents

Amoeba Sisters Video Recap of Meiosis

Calculating GPP and NPP

Endocrine System

AS Biology Paper 1 2024

Kami Export - Sandra Nichols - Bio-Worksheet-Mutat

Cami Salazar Correa Cell Energy Cycle Gizmo

11 Transport in Cells S

Protein Structure

Dihybrid Cross Amoeba Sisters Video Recap

11 Transport in Cells-S (KEY)

Company

Explore

Study Tools