07 Inheritance and Adaptations

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Supplemental
Worksheets
Name
Date
Class
Quick Vocabulary
Lesson 1
Lesson 2
gene section of DNA that has genetic
adaptation inherited trait that
information for one trait
genotype organism’s complete set of
genes
inheritance passing of traits from
generation to generation
mutation permanent change in the
sequence of DNA in a gene
phenotype how a trait appears or is
expressed
population all the members of a
species living in a given area
random without a definite aim, rule,
or method
trait distinguishing characteristic of
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
an organism
helps a species survive in
its environment
camouflage adaptation that helps a
species blend in with its natural
surroundings
mimicry adaptation in which one
species looks like another species
natural selection process by which
organisms with variations that help
them survive in their environment
live longer, compete better, and
reproduce more than those that do
not have the variation
selective breeding selection and
breeding of organisms with desired
traits
species group of organisms that
share similar characteristics and
can reproduce among themselves,
producing fertile offspring
variation slight difference in
inherited traits among individual
members of a species
Inheritance and Adaptations
3
Name
Date
Class
Lesson Outline
LESSON 1
Inheritance and Traits
A. What is inheritance?
1. A(n)
is a distinguishing characteristic of an organism.
2. The passing of traits from generation to generation is
called
.
3. A trait that an organism acquires or develops during its lifetime is called
a(n)
trait.
B. Inheritance and DNA
1. Amoebas, bacteria, and some plants pass traits to their offspring by cell division
and mitosis, a process called
2.
reproduction.
reproduction results in offspring that are identical to
the original organism.
3.
reproduction produces offspring that are similar to but
not identical to the parent or parents.
4. Sexual reproduction requires DNA from a(n)
cell and
an egg cell.
that looks like a twisted
zipper.
a. A section of DNA that has genetic information for one trait is called
a(n)
b. A(n)
.
is a structure made of long chains of DNA.
6. In most species,
come in pairs.
a. Humans have 23 pairs of chromosomes in each
b. Human sperm and eggs, or
cell.
cells, each contain
23 single chromosomes.
C. Combining Genes
1. During sexual reproduction, an egg cell and a(n)
cell
each contribute one gene for a trait.
2. Each gene for a single trait is called a(n)
10
.
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
5. DNA is a molecule inside a cell’s
Name
Date
Class
Lesson Outline continued
3. The process in which sperm and egg cells form is called
.
a. During meiosis, the chromosomes in existing egg and sperm cells
and divide.
b. Meiosis results in
separate cells, each with half the
number of chromosomes the original cells had.
4. During
, egg cell chromosomes and the sperm cell
chromosomes combine to form an offspring with a full set of paired chromosomes.
5. Each
resulting from sexual reproduction is unique
because each sperm cell and egg cell is unique.
D. Influencing Traits
1. An organism’s
is its complete set of genes.
2. The traits expressed by the genotype can be influenced by an
organism’s
.
3. How a trait appears, or is expressed, is called the trait’s
.
a. Phenotypes result from the interaction between an organism’s
and its environment.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
b. Nutrients can cause dramatic changes in the
of plants
and animals.
c. An organism’s
group also can affect color, body
structure, or behavior.
4. A change in phenotype in response to environment does not affect an organism’s
genes and the change is not passed on to future
.
5. A permanent change in the sequence of DNA in a gene is called
a(n)
.
a. A mutation in a gene can change the
for which the
gene holds information.
b. All genes can mutate, but only mutated genes in egg or
cells can be
6. Many mutations do not help or
.
an organism.
7. Mutations that change an organism’s genes so much that they can affect an
organism’s ability to
or helpful.
Inheritance and Adaptations
in its environment can be harmful
11
Name
Date
Class
Content Practice A
LESSON 1
Inheritance and Traits
Directions: Complete the crossword puzzle with the correct terms from the word bank.
gene
genotype
inheritance
mutation
phenotype
trait
2
1
3
4
5
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
6
Across
1. a distinguishing characteristic of an
organism
5. a section of DNA that has genetic
information for one trait
6. a permanent change in the sequence of
Down
2. the passing of traits from generation to
generation
3. an organism’s complete set of genes
4. how a trait appears or how it is
expressed
DNA in a gene
Inheritance and Adaptations
13
Name
Date
Class
Content Practice B
LESSON 1
Inheritance and Traits
Directions: On the line before each trait, write I if the trait describes an inherited trait or A if the trait describes
an acquired trait.
1. color of wings
2. length of hair
3. color of eyes
4. shape of nose
5. loss of limb
6. shape of scar
Directions: Circle the term in parentheses that correctly completes each sentence.
7. Sperm and eggs are human (body/reproductive) cells.
8. Each human sperm and egg contains (23/46) chromosomes.
9. (Mutation/Meiosis) is the process during which sperm and egg cells form.
11. Because each sperm cell and egg cell is (unique/similar), the resulting offspring also is
(unique/similar).
12. In humans, there are (many/few) potential gene arrangements from the union of sperm
and egg chromosomes.
14
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
10. During (meiosis/fertilization), a sperm and an egg unite.
Name
Date
Math Skills
Class
LESSON 1
Use Probability
Genes are chemical codes that carry information about how an organism grows and functions.
The genes in a cell are grouped into larger molecules called chromosomes. A body cell
contains two different versions of each chromosome. Many animals and plants pass genes
to their offspring by sexual reproduction. During sexual reproduction, the chromosomes are
duplicated and then divided into egg or sperm cells. An egg or sperm cell contains a single
version of each chromosome.
The possible number of unique combinations of chromosomes in an egg or sperm cell
depends on the number of chromosomes in the organism. The formula 2n predicts the
number of chromosome combinations, where n is the total number of chromosomes
divided by two.
The expression 2n is a short way to write repeated multiplication of a number by itself. The
base is the number, 2, and the exponent is the raised number, n. The exponent shows the
number of times you multiply the base by itself. You might need to use a calculator to solve
the problems.
A pea plant has 14 chromosomes. How many different combinations of chromosomes can
be produced in the offspring?
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Step 1
Divide the number of chromosomes by 2.
14 chromosomes
______________
=7
2
Step 2
Substitute for n in the expression 2n.
2n = 27 = 2 × 2 × 2 × 2 × 2 × 2 × 2 = 128
Practice
1. A mosquito has 6 chromosomes.
How many different chromosome
combinations can form in the offspring?
2. Corn has 20 chromosomes. How many
different chromosome combinations
can form in the offspring?
Inheritance and Adaptations
3. A human has 46 chromosomes.
How many different chromosome
combinations can form in the offspring?
4. A capuchin monkey has
54 chromosomes. How many different
chromosome combinations can form
in the offspring?
15
Name
Date
Class
Key Concept Builder
LESSON 1
Inheritance and Traits
Key Concept What is inheritance?
Directions: Answer each question or respond to each statement in the space provided.
Question
Answer
1. What is a trait?
2. What is inheritance?
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
3. Inheritance occurs during which process?
4. What are inherited traits?
5. Give an example of an inherited trait.
6. What are acquired traits?
7. Give an example of an acquired trait.
Inheritance and Adaptations
17
Name
Date
Class
Key Concept Builder
LESSON 1
Inheritance and Traits
Key Concept What is the role of genes in inheritance?
Directions: Label this diagram by writing the correct term from the word bank on each line.
cell nucleus
chromosome
1.
DNA strands
gene
3.
2.
4.
Directions: Answer each question or respond to each statement on the lines provided.
6. What is the role of genes in inheritance?
7. Describe the two ways in which organisms pass inherited traits to their offspring.
18
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
5. How are genes related to DNA?
Name
Date
Class
Key Concept Builder
LESSON 1
Inheritance and Traits
Key Concept How do environmental factors influence traits?
Directions: On each line, write the term from the word bank that correctly completes each sentence. Some terms
will be used more than once.
environment
genotype
nutrients
phenotype
physical factors
social factors
social group
social phase
solitary phase
1. An organism’s complete set of genes is its
2. The
.
of a trait is how the trait appears or how it is expressed.
3. A(n)
is unchanged throughout an organism’s life.
4. A(n)
can change throughout an organism’s life.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
5. Phenotypes result from the interactions of an organism’s genes and
its
.
6. Light, temperature, and moisture are
that can influence
an organism’s phenotype.
7. Flamingos are born white, but they turn pink because of the food they eat; this is an
example of how
8.
, a physical factor, can affect phenotypes.
can also affect an organism’s color, body structure, or
behavior.
9. The size of a desert locust’s
10. The desert locust is green in its
11. The desert locust is yellowish-brown in its
Inheritance and Adaptations
can affect its phenotype.
.
.
19
Name
Date
Class
Key Concept Builder
LESSON 1
Inheritance and Traits
Key Concept How do mutations influence traits?
Directions: On the line before each statement, write T if the statement is true or F if the statement is false. If the
statement is false, change the underlined word(s) to make it true. Write your changes on the lines provided.
1. When an organism’s genotype changes in response to its environment, the
organism’s genes are not affected and the change can be passed on to the next
generation.
2. A mutation is a temporary change in the sequence of DNA in a gene.
3. A mutation is the only way that a trait can change so it can be passed to
the next generation.
4. Only mutated genes in egg or sperm cells are inherited.
6. Mutations can affect an organism’s ability to survive in its environment.
7. Mutations are always harmful to an organism.
8. Mutations can spread to an entire population.
20
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
5. Few mutations occur randomly.
Name
Date
Class
Lesson Quiz A
LESSON 1
Inheritance and Traits
Multiple Choice
Directions: On the line before each question, write the letter of the correct answer.
1. Which trait is NOT inherited?
A. height
B. hair color
C. writing skill
2. Which statement is true of chromosomes?
A. They are made up of DNA.
B. They destroy genes in egg cells.
C. They exist in cell groups of threes.
3. Which factor determines whether flamingoes will mate?
A. genotype
B. mutations
C. environment
Matching
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term
is used only once.
4. a permanent change in DNA sequence
A. genotype
5. section of DNA with genetic information for one
B. mutation
trait
C. phenotype
6. the complete set of genes of an organism
D. trait
7. how a distinguishing characteristic appears
E. gene
8. a distinguishing characteristic of an organism
Inheritance and Adaptations
23
Name
Date
Class
Lesson Quiz B
LESSON 1
Inheritance and Traits
Short Answer
Directions: Respond to each statement on the lines provided.
1. Compare and contrast the types of characteristics that are inherited and not inherited.
2. Describe the role that chromosomes play in inheritance.
3. Explain how the environment can often play a role in determining phenotype.
Directions: On the line before each definition, write the letter of the term that matches it correctly. Not all terms
are used.
4. a permanent change in DNA sequence
A. chromosome
5. section of DNA that has genetic information for
B. genotype
one trait
C. meiosis
6. the complete set of genes of an organism
D. mutation
7. how a distinguishing characteristic appears
E. phenotype
8. a distinguishing characteristic of an organism
F. trait
G. gene
24
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Matching
Name
Date
Class
Lesson Outline
LESSON 2
Adaptations in Species
A. What is adaptation?
1.
are slight differences in inherited traits among
individual members of a species.
2. Variations occur through
, which can be harmful, not
harmful, or beneficial.
3. An inherited trait that helps a species survive in its environment is called
a(n)
.
B. How Adaptations Occur
1. The process by which organisms with variations that help them survive in their
environment live longer, compete better, and reproduce more than those that do
not have the variation is called
.
a. A variation that helps an organism
or compete better
in its environment enables the organism with that variation to live longer.
b. An organism that lives longer tends to have more
that
also can have the variation.
c. Over many
, more and more offspring inherit a
d. Once most of a population have a beneficial variation, it becomes
a(n)
.
2. New variations are random and occur continually because
are random and occur continually.
3. When an environment changes, a population must
through natural selection or it will die off.
4.
is the selection and breeding of organisms that have
desired traits.
5. Selective breeding is similar to natural selection except, instead of nature,
do the selecting.
C. Types of Adaptations
1. Adaptations enable species to maintain
, avoid
, find and eat food, and move.
28
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
beneficial variation.
Name
Date
Class
Lesson Outline continued
2. The three main categories of adaptations are structural, behavioral,
and
.
a. A structural adaptation is a(n)
trait, such as color,
shape, or internal structure, that increases survival.
b. A behavioral adaptation is a behavior or
such as
migration, hibernation, hunting at night, or playing dead, that increases survival.
c. A functional adaptation is a(n)
change such as
hibernating, shedding, or spitting, that enables a species to increase survival or
maintain homeostasis.
3.
is the ability of an organism to keep its internal
conditions within certain limits.
4. Adaptations that protect organisms from predators include
that make an organism resemble something else.
a. Adaptations that enable a species to blend in with its environment are
called
.
b. An adaptation in which one species looks like another species is
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
called
.
5. Adaptations such as camouflage and mimicry that protect species from predators can
also help species find
.
6. Some plants have adaptations such as modified underground
that enable them to store food.
7. Adaptations that help species move include
, wings,
flippers, fins, and tails.
8. Movement helps species search for food, avoid predators, and escape
unpleasant
Inheritance and Adaptations
.
29
Name
Date
Class
Content Practice A
LESSON 2
Adaptations in Species
Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term
is used only once.
1. a slight difference in inherited traits among
individual members of a species
A. adaptation
B. behavioral adaptation
C. camouflage
2. a trait that helps a species survive in its
environment
D. functional adaptation
E. mimicry
3. a process by which organisms that have variations
that help them survive in their environment live
longer, compete better, and reproduce more than
those that do not have the variation
F. natural selection
G. selective breeding
H. structural adaptation
I. variation
4. the selection and breeding of organisms that have
desired traits
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
5. a physical trait that increases survival
6. a behavior or action that increases survival
7. a biochemical change that increases survival
8. an adaptation that helps a species blend in with
its environment
9. an adaptation in which one species looks like
another species
Inheritance and Adaptations
31
Name
Date
Content Practice B
Class
LESSON 2
Adaptations in Species
Directions: On the line after each adaptation, write S if the adaptation is a structural adaptation, B if the
adaptation is a behavioral adaptation, or F if the adaptation is a functional adaptation.
1. hibernation
2. eye color
3. spitting
4. shedding
5. migration
6. body shape
7. playing dead
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
8. hunting at night
9. internal structure
Directions: Answer each question or respond to each statement on the lines provided.
10. What is homeostasis?
11. Give an example of how your body maintains homeostasis.
32
Inheritance and Adaptations
Name
Date
Class
Language Arts Support
LESSON 2
Word-Usage Activity: Avoiding Double Negatives
Some words have positive meanings, and others have negative meanings. You only need to
use one negative word in a sentence to convey a negative meaning.
When two negative words are used together, it is called a double negative. You should avoid
using double negatives.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Positive
Negative
is, are
isn’t, aren’t
can
can’t
will
won’t
ever, always
never
anybody, somebody
nobody
one, all
none
everyone, someone
no one
something, anything
nothing
somewhere, anywhere
nowhere
some, any
scarcely, hardly
Directions: Underline the correct word in parentheses that completes each sentence.
1. Nobody (could, couldn’t) identify where the inherited traits came from.
2. He didn’t do (nothing, anything) to prepare for the test.
3. When it is stretched out, DNA (is, isn’t) never 5 m long.
4. Environmental factors such as light, temperature, and moisture aren’t (ever, never)
constant in any environment.
5. Don’t use (any, no) fertilizer on that plant; it has more than enough already.
6. She would not do (none, any) of her homework.
7. No solitary desert locusts are (never, ever) the same color as they are in the swarm.
Inheritance and Adaptations
33
Name
Date
Class
Language Arts Support
LESSON 2
Mechanics Activity: Semicolons and Colons
You can use a semicolon to join parts of a compound sentence when the words or, and, or
but are not used. In the sentence below, a compound sentence is connected using a comma
and the word but:
If an organism’s phenotype changes in response to the environment, its genotype does
not change, but if an organism’s genotype changes with a mutation, the changes are
passed to the next generation.
A semicolon can connect the compound sentence without using a comma or the word but:
If an organism’s phenotype changes in response to the environment, then its genotype
does not change; if an organism’s genotype changes with a mutation, then the changes
are passed to the next generation.
You can use a colon to introduce a list of items at the end of a sentence:
The phenotype is affected by environmental factors: light, temperature, moisture,
nutrients, and social factors.
Directions: Insert colons or semicolons as needed in the sentences below.
1. All genes can mutate only sperm and egg mutations are passed on to the next generation.
2. The social group of an organism can affect several factors color, behavior, and body
structure.
maintain homeostasis, to find food, and to eat.
4. Some mutations have no effect on an organism they do not hurt or help.
5. Natural selection results in changes in traits selective breeding also results in changes in
traits.
6. Adaptations in organisms come in three main groups structural, behavioral, and
functional.
7. When the environment changes quickly, a population might adapt to survive a
population might also fail to adapt, and the species could go extinct.
34
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
3. An organism might develop an adaptation for a number of purposes to move, to
Name
Date
Class
Key Concept Builder
LESSON 2
Adaptations in Species
Key Concept How do mutations cause variations?
Directions: On the line before each statement, write the letter of the correct answer.
1. Offspring are different from their parents because of the process of
A. selective breeding.
B. sexual reproduction.
C. asexual reproduction.
2. Slight differences in inherited traits among individual members of a species
are called
A. genes.
B. variations.
C. acquired traits.
3. Variations occur through
A. mutations.
B. fertilization.
C. adaptations.
5. A trait that helps a species survive in its environment is a(n)
A. variation.
B. mutation.
C. adaptation.
6. Giraffe spots are an example of a mutation that became part of the giraffe
population’s
A. mimicry.
B. genotype.
C. environment.
36
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
4. A mutation can
A. help an organism.
B. harm an organism.
C. harm or help an organism.
Name
Date
Key Concept Builder
Class
LESSON 2
Adaptations in Species
Key Concept How does natural selection lead to adaptations in species?
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Directions: Label this diagram by writing a caption for each part of the diagram on the lines provided.
1.
2.
3.
4.
Directions: Answer the question on the lines provided.
5. What is natural selection?
Inheritance and Adaptations
37
Name
Date
Class
Key Concept Builder
LESSON 2
Adaptations in Species
Key Concept What are some ways adaptations help species survive in their environments?
Directions: Complete the concept map using the correct terms from the word bank in the space provided.
behavioral adaptation
biochemical change
physical trait
playing dead
spraying venom
structural adaptation
Types of
Adaptation
behavior or
action
color and
shape of eyes
38
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
functional
adaptation
Name
Date
Class
Key Concept Builder
LESSON 2
Adaptations in Species
Key Concept What are some ways adaptations help species survive in their environments?
Directions: On each line, write the term from the word bank that correctly completes each sentence. Each term
is used only once.
adaptations
camouflage
homeostasis
predators
prey
sweating
(1.)
mimicry
help species maintain homeostasis, avoid predators,
find and eat food, and move. The ability of an organism to keep its internal conditions
within certain limits is called (2.)
(3.)
.
is an example of how the human body maintains
homeostasis. Species also have adaptations to protect themselves from animals that hunt, or
(4.)
. For example, (5.)
is an
adaptation that helps a species blend in with its natural surroundings.
(6.)
is an adaptation in which one species looks like another
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
species. Camouflage and mimicry also help species hide from the animals they hunt, or
their (7.)
.
Directions: In the space provided, draw the beak of a bird that is adapted to search for insects in a tree and the
beak of a bird that is adapted to crack open hard nuts. Label your drawing.
Inheritance and Adaptations
39
Name
Date
Class
Lesson Quiz A
LESSON 2
Adaptations in Species
True or False
Directions: On the line before each statement, write T if the statement is true or F if the statement is false. If the
statement is false, change the underlined word(s) to make it true. Write your changes on the lines provided.
1. A behavioral adaptation is a biochemical change within an organism that helps
it survive or maintain homeostasis.
2. Natural selection occurs when humans select and breed organisms that have
desired traits.
3. The ability of an organism to maintain internal conditions within certain limits
within a changing environment is called homeostasis.
Matching
Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term
is used only once.
A. adaptation
5. a trait that is beneficial to a species
B. camouflage
6. process by which beneficial variations help some
C. mimicry
organisms reproduce more
7. an adaptation that helps a species blend in with
D. natural selection
E. variation
surroundings
8. an adaptation that helps one species appear to
be a different species
42
Inheritance and Adaptations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
4. the result of mutations
Name
Date
Class
Lesson Quiz B
LESSON 2
Adaptations in Species
Short Answer
Directions: Respond to each statement on the lines provided.
1. Name a functional adaptation that helps a species survive.
2. Explain how selective breeding differs from natural selection.
3. Point out why homeostasis requires adaptation to a changing environment.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Matching
Directions: On the line before each definition, write the letter of the term that matches it correctly. Not all terms
are used.
4. the result of mutations
A. adaptation
5. a trait that is beneficial to a species
B. camouflage
6. process by which beneficial variations help some
C. extinction
organisms reproduce more
7. an adaptation that helps a species blend in with
surroundings
8. an adaptation that helps one species appear to
D. mimicry
E. natural selection
F. selective breeding
G. variation
be a different species
Inheritance and Adaptations
43
Lesson Outline for Teaching
Lesson 1: Inheritance and Traits
A. What is inheritance?
1. A(n) trait is a distinguishing characteristic of an organism.
2. The passing of traits from generation to generation is called inheritance.
a(n) acquired trait.
3. A trait that an organism acquires or develops during its lifetime is called
B. Inheritance and DNA
and mitosis, a process called asexual reproduction.
1. Amoebas, bacteria, and some plants pass traits to their offspring by cell division
2. Asexual reproduction results in offspring that are identical to the original organism.
3. Sexual reproduction produces offspring that are similar to but not identical to the
parent or parents.
4. Sexual reproduction requires DNA from a(n) sperm cell and an egg cell.
a. A section of DNA that has genetic information for one trait is called a(n) gene.
5. DNA is a molecule inside a cell’s nucleus that looks like a twisted zipper.
b. A(n) chromosome is a structure made of long chains of DNA.
6. In most species, chromosomes come in pairs.
a. Humans have 23 pairs of chromosomes in each body cell.
b. Human sperm and eggs, or reproductive cells, each contain 23 single chromosomes.
and egg cell is unique.
62
Inheritance and Adaptations
5. Each offspring resulting from sexual reproduction is unique because each sperm cell
combine to form an offspring with a full set of paired chromosomes.
4. During fertilization, egg cell chromosomes and the sperm cell chromosomes
the original cells had.
b. Meiosis results in four separate cells, each with half the number of chromosomes
and divide.
a. During meiosis, the chromosomes in existing egg and sperm cells replicate
3. The process in which sperm and egg cells form is called meiosis.
2. Each gene for a single trait is called a(n) allele.
gene for a trait.
1. During sexual reproduction, an egg cell and a(n) sperm cell each contribute one
C. Combining Genes
T2
3/31/10
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Lesson Outline continued
1. An organism’s genotype is its complete set of genes.
D. Influencing Traits
2. The traits expressed by the genotype can be influenced by an organism’s environment.
3. How a trait appears, or is expressed, is called the trait’s phenotype.
environment.
a. Phenotypes result from the interaction between an organism’s genes and its
b. Nutrients can cause dramatic changes in the phenotypes of plants and animals.
c. An organism’s social group also can affect color, body structure, or behavior.
genes and the change is not passed on to future generations.
4. A change in phenotype in response to environment does not affect an organism’s
a. A mutation in a gene can change the trait for which the gene holds information.
5. A permanent change in the sequence of DNA in a gene is called a(n) mutation.
b. All genes can mutate, but only mutated genes in egg or sperm cells can be inherited.
6. Many mutations do not help or hurt an organism.
organism’s ability to survive in its environment can be harmful or helpful.
7. Mutations that change an organism’s genes so much that they can affect an
Discussion Question
Describe the structure of a chromosome.
Inheritance and Adaptations
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A chromosome is a structure made of long chains of DNA. The DNA is tightly coiled with
proteins, forming a compact chromosome that fits into a cell’s nucleus.
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Lesson Outline for Teaching
Lesson 2: Adaptations in Species
A. What is adaptation?
of a species.
1. Variations are slight differences in inherited traits among individual members
or beneficial.
2. Variations occur through mutations, which can be harmful, not harmful,
adaptation.
3. An inherited trait that helps a species survive in its environment is called a(n)
B. How Adaptations Occur
1. The process by which organisms with variations that help them survive in their
environment live longer, compete better, and reproduce more than those that do
not have the variation is called natural selection.
enables the organism with that variation to live longer.
a. A variation that helps an organism survive or compete better in its environment
b. An organism that lives longer tends to have more offspring that also can have the
variation.
c. Over many generations, more and more offspring inherit a beneficial variation.
d. Once most of a population have a beneficial variation, it becomes a(n) adaptation.
and occur continually.
2. New variations are random and occur continually because mutations are random
or it will die off.
3. When an environment changes, a population must adapt through natural selection
traits.
4. Selective breeding is the selection and breeding of organisms that have desired
do the selecting.
5. Selective breeding is similar to natural selection except, instead of nature, humans
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Inheritance and Adaptations
or spitting that enables a species to increase survival or maintain homeostasis.
c. A functional adaptation is a(n) biochemical change, such as hibernating, shedding,
hunting at night, or playing dead that increases survival.
b. A behavioral adaptation is a behavior or action, such as migration, hibernation,
structure, that increases survival.
a. A structural adaptation is a(n) physical trait, such as color, shape, or internal
2. The three main categories of adaptations are structural, behavioral, and functional.
food, and move.
1. Adaptations enable species to maintain homeostasis, avoid predators, find and eat
C. Types of Adaptations
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Lesson Outline continued
limits.
3. Homeostasis is the ability of an organism to keep its internal conditions within certain
an organism resemble something else.
4. Adaptations that protect organisms from predators include variations that make
camouflage.
a. Adaptations that enable a species to blend in with its environment are called
b. An adaptation in which one species looks like another species is called mimicry.
also help species find food.
5. Adaptations such as camouflage and mimicry that protect species from predators can
to store food.
6. Some plants have adaptations such as modified underground stems that enable them
7. Adaptations that help species move include legs, wings, flippers, fins, and tails.
stimuli.
8. Movement helps species search for food, avoid predators, and escape unpleasant
Discussion Question
Do all variations affect an organism’s chances of survival? Explain your answer.
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No, not all variations affect an organism’s chances of survival. A mutation could hurt or
help an organism, but it could also have no effect on the organism’s survival.
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