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Chapter 7 Section 2 Sexual Reproduction Objectives Differentiate between asexual and sexual reproduction. Identify three types of asexual reproduction. Evaluate the relative genetic and evolutionary advantages and disadvantages of asexual and sexual reproduction. Differentiate between the three major sexual life cycles found in eukaryotes.
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7.2 Vocabulary Asexual reproduction Clone Sexual reproduction
Life cycle Fertilization Sporophyte Spore Gametophyte
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Reproduction asexual Reproduction can be ________________ or _________________ The type of reproduction that produces an offspring determines how similar the organism is to its ________________ and _______________ sexual parents siblings
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Chapter 7 Asexual Reproduction primitive
Section 2 Sexual Reproduction Asexual Reproduction primitive Most ___________ form of reproduction Occurs when a ___________ parent passes _________ copies of all of its genes to each of its offspring there is no ________________ of haploid cells such as gametes. An individual produced by asexual reproduction is a _______________, meaning that it is genetically identical to its parent. single exact fusion clone
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Cloning usually occurs with _____________ life forms, but scientists have been using genetic engineering to clone more ____________ organisms To clone an animal, the nucleus of an ________________ cell is placed into an ______ whose nucleus has been removed. This altered egg cell is placed in the uterus of the ________________ mother , who gives birth to the clone simple complex egg Embryonic or somatic surrogate
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Dolly In 1996, the sheep dolly made news because she was the first clone that developed from a _______________________ adult cell To clone Dolly, a nucleus was taken from an adult _______________ cell instead of an embryonic cell …this experiment shows that ________________ body cells are capable of producing new organisms differentiated udder somatic
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It appears that when adult cells are cloned, the resulting organisms experience __________________ aging The average life span for sheep is 12 years, but Dolly developed arthritis at only ______ years old and was euthanized in 2003 premature 5
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Chapter 7 There are Three Types of Asexual Reproduction
Section 2 Sexual Reproduction There are Three Types of Asexual Reproduction __________________________ Fission Fragmentation Budding
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Fission During fission, a parent separates into two individuals of about __________ size. Occurs in single celled _______________ like an ______________ equal eukaryotes amoeba
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Fragmentation Type of reproduction in which the body breaks into __________ pieces and each fragment develops into a new individual May be __________________ or _______________ Occurs in some _______________ eukaryotes, like… ________________ several intentional unintentional multicellular annelid worms starfish
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Budding Occurs when new individuals _______ off from existing ones.
split Hydra Simple freshwater animal
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Advantages of Asexual Reproduction
many Allows organisms to produce ________ offspring in a _________ period of time They do not waste time and energy… Producing ______________ Finding a _____________ short gametes mate
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Disadvantages of Asexual Reproduction
little DNA varies ___________ among organisms Populations may not be able to __________ in a changing environment survive
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Sexual Reproduction 2 In sexual reproduction, _____ parents each produce gametes containing _______ the number of chromosomes needed in an organism As the gametes combine through the process of ___________________, they produce offspring containing a ___________ combination of genes These new combinations of genes allow species to ____________ half fertilization unique evolve
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Why did sexual reproduction originate?
Only __________ cells contain enzymes that can repair damage to _________ However, many early life forms, such as ____________, exist mainly in a haploid state. diploid DNA protists
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What are protists? Single celled organisms that contain a _____________ They form diploid cells in response to __________ in their environment So _____________ together through sexual reproduction may have provided them a chance to correct damages to their DNA nucleus stress joining
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Sexual Life Cycles in Eukaryotes
Chapter 7 Section 2 Sexual Reproduction Sexual Life Cycles in Eukaryotes The entire span in the life of an organism from one generation to the next is called a _______________. The life cycles of all sexually reproducing organisms follows a basic pattern of _______________ between ____________ and ______________ chromosome numbers. life cycle alternation diploid haploid
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You can get all of the life cycle questions correct if you remember…
That mitosis makes _____________ And meiosis cuts the chromosome number in _________ copies half
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Eukaryotes that undergo sexual reproduction can have one of three types of sexual life cycles…
____________________ Diploid Haploid Alternation of Generations
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Chapter 7 Diploid Life Cycle diploid meiosis Adult individuals
Section 2 Sexual Reproduction Diploid Life Cycle Adult individuals consist of ________ cells A diploid cell goes through _______________ to produce gametes diploid meiosis
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Chapter 7 Diploid Life Cycle zygote mitosis Through fertilization,
Section 2 Sexual Reproduction Diploid Life Cycle Through fertilization, gametes unite to make a __________ that develops into an adult through the process of _____________ zygote mitosis
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Chapter 7 Haploid Life Cycle Simplest haploid
Section 2 Sexual Reproduction Haploid Life Cycle Simplest _____________ life cycle Organisms spend the majority of their life as _____________ individuals haploid
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Chapter 7 Haploid Life Cycle mitosis fuse 2n
Section 2 Sexual Reproduction Haploid Life Cycle Gametes are made through the process of ____________, rather than meiosis Gametes ________ to make a _____ zygote mitosis fuse 2n
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Chapter 7 Haploid Life Cycle meiosis pair
Section 2 Sexual Reproduction Haploid Life Cycle The zygote immediately goes through _____________, during which homologous chromosomes ________ up meiosis pair
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Chapter 7 Haploid Life Cycle check
Section 2 Sexual Reproduction Haploid Life Cycle When they are paired, enzymes have a chance to ___________ the DNA and correct any damages check
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Chapter 7 Haploid Life Cycle protists fungi algae Occurs in many
Section 2 Sexual Reproduction Haploid Life Cycle Occurs in many _____________, as well as in some and __________ protists fungi algae
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Alternation of Generations
Chapter 7 Section 2 Sexual Reproduction Alternation of Generations Occurs in all ___________ This life cycle ______________ alternates between haploid and diploid stages plants regularly
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Chapter 7 In some plants, the dominant stage is called a _____________
Section 2 Sexual Reproduction In some plants, the dominant stage is called a _____________ It is _____ and produces _____________ through the process of meiosis sporophyte 2n spores
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Spores are special reproductive cells…
that have ________________ outer coverings and that can develop into a multicellular individual ___________ joining another spore protective without
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Chapter 7 In flowering plants, spores are actually not ___________
Section 2 Sexual Reproduction In flowering plants, spores are actually not ___________ They stay in the tissue of the sporophyte plant and develop into _____________ released gametophytes
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Chapter 7 Section 2 Sexual Reproduction Most gametophytes are very _________; in flowering plants, they cannot be seen without the aid of a microscope tiny
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Chapter 7 Section 2 Sexual Reproduction Gametophytes produce _____________through the process of _____________ The gametes consist of male __________ grains and female ______ gametes mitosis pollen eggs
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Chapter 7 Section 2 Sexual Reproduction The gametes unite during fertilization and develop into a large ____________ sporophyte
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ferns In other types of plants, like ________, spores are ____________ released Sporophyte (2n) Gametophyte (n)
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moss In plants like ____________, the sporophyte (2n) actually grows out of the gametophyte (n) Gametophyte (n)
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Objective 1 Differentiate between asexual and sexual reproduction.
One parent Two parents Gametes fuse Exact copies Genetic variation
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Objective 2 Identify three types of asexual reproduction. Fission
Fragmentation Budding
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Objective 3 Evaluate the relative genetic and evolutionary advantages and disadvantages of asexual and sexual reproduction. More variation in offspring and DNA can be checked for errors Saves time and energy But populations consist of clones More time consuming and requires more energy
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Objective 4 Differentiate between the three major sexual life cycles found in eukaryotes. Diploid Gametes made by meiosis, gametes fuse to make a zygote Haploid Gametes made by mitosis, zygote uses meiosis to turn back into haploid cells Alternation of Generations Occurs in plants, meiosis makes spores and gametes are made by mitosis
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