Chapter 7 - Reproduction1 Reproduction Chapter 7

Chapter 7 - Reproduction2 Reproduction – Making Offspring oOne of the characteristics of living organisms is their ability to reproduce. oReproduction can be identified as either: oAsexual oSexual o Asexual reproduction involves a single parent and produces offspring that are clones. o Sexual reproduction involves genetic contributions from two sources in the form of gametes.

Chapter 7 - Reproduction3 Reproduction – Making Offspring oQuick Check Questions 1-3

Chapter 7 - Reproduction4 Reproduction Without Sex oReproduction is asexual when offspring are produced from a single parent. oIn all cases of asexual reproduction, the offspring are identical with each other and with the parent. oExamples of asexual reproduction include: oBinary fission in microbes oSplitting in single celled organisms oSpore formation in fungi oCloning oCuttings from plants

Chapter 7 - Reproduction5 Binary Fission (Two Splitting) oMicrobes such as bacteria consist of unicellular prokaryotic cells. oMultiplication of bacterial cells occur by an asexual process of reproduction known as binary fission.

Chapter 7 - Reproduction6 Binary Fission (Two Splitting) oThe binary fission of a bacterial cell involves: 1.Replication of the circular model of DNA of the bacteria. 2.Attachment of the DNA molecules to the plasma membrane. 3.Lengthening of the cell. 4.Physical division of the into two.

Chapter 7 - Reproduction7 Binary Fission (Two Splitting) oBinary fission in bacterial cells can be completed in 20 minutes at room temperature. oTherefore with one cell left to reproduce over an 8 hour period, will be left with: o20min – 2 cells o40min – 4 cells o60min – 8 cells o8 hours – cells oThis is an example of exponential growth.

Chapter 7 - Reproduction8 Splitting of Cells oSome eukaryotic unicellular organisms, such as Amoeba, can reproduce asexually by splitting into two. oThis process is also known as binary fission, however this is different to what bacteria undergo because eukaryotic cells undergo the process of mitosis.

Chapter 7 - Reproduction9 Budding oSponges are common in many marine habitats. oEach sponge is made of thousands of cells with no specialised organs. oSponges are able to reproduce asexually from small groups of cells formed by mitosis that bud or break away from the main organism. oThese buds are carried by currents where they settle and develop into new sponges.

Chapter 7 - Reproduction10 Asexual Reproduction In Plants oAsexual reproduction is common in plants. It is also known as vegetative reproduction. oExamples of asexual reproduction in plants include: oRunners oCuttings oRhizomes oTubers oBulbs oSuckers oExamples of these can be seen on pages of the text.

Chapter 7 - Reproduction11 Asexual Reproduction In Plants oQuick Check Questions 4-8 p186

Chapter 7 - Reproduction12 Sexual Reproduction oMost commonly, sexual reproduction involves a male and a female parent, each of which makes a genetic contribution to each offspring. oThe genetic contribution from each parent is a single cell, either a sperm or an egg. oThis type of sexual reproduction is common in most animals, however it is not the case for some animals and all flowering plants.

Chapter 7 - Reproduction13 Sexual Reproduction in Plants oIf you examine a flower, the most common situation is that it will have both pollen producing organs (stamens) and egg producing organs (carpels). oIn flowering plants, the female gamete is called an egg and the egg producing organ is the carpel (or pistil). oThe male gamete is the pollen produced by the stamen.

Chapter 7 - Reproduction14 Sexual Reproduction in Plants

Chapter 7 - Reproduction15 Sexual Reproduction in Plants oCone-bearing plants, such as pines and firs, do not have flowers but they produce eggs and pollen on different types of cones. oFerns and mosses have neither flowers nor cones but they produce eggs and sperm in specialised sex organs at one stage of their life cycle.

Chapter 7 - Reproduction16 Life Cycles of Plants Have Two Stages oThe dominant part of the life cycle in a plant is in a diploid form (2n), but the life cycle includes a tiny, independently time living as a haploid plant (n). oThe diploid plant produces spores by meiosis. Spores usually develop on the underside of a frond in structures known as sori and these spores develop into tiny haploid plants. oThese tiny plants produce gametes by mitosis that after fusing, develop into sporophytes and the cycle is completed.

Chapter 7 - Reproduction17 Life Cycles of Plants Have Two Stages

Chapter 7 - Reproduction18 Comparing Life Cycles of Plants & Animals

Chapter 7 - Reproduction19 Animals – Just What Sex Are You? oIn some animal species, a single organism has both egg-producing and sperm producing organs. oThese organisms are termed hermaphrodites and include the garden snail and the common earthworm. oWhen both sperm and egg producing organs are active in the organism at the same time, is called simultaneous hermaphrodism. oIn contrast, some coral fish species actually change their sex to suit their environment. They are called sequential hermaphrodites.

Chapter 7 - Reproduction20 Animals – Just What Sex Are You?

Chapter 7 - Reproduction21 Sex in Flowering Plants oAs noted previously, that most flowering plants have both pollen producing organs (stamens) and egg producing organs (carpels). oMost commonly, flowers on a plant will only contain one or the other (male or female flowers). These plants are said to be dioecious. oLess frequently, a plant may contain both male and female flowers in their active form on the plant. These plants are referred to as monoecious.

Chapter 7 - Reproduction22 Sex in Flowering Plants oQuick Check Questions 9-11 p191

Chapter 7 - Reproduction23 Getting Gametes Together oIn sexual reproduction, two parental contributions (egg & sperm) fuse together to produce a zygote that will then develop into an animal or a plant. o Fertilisation is the fusion of two gametes. oSome animals release their gametes into the external environment so that fertilisation occurs outside the body - External Fertilisation. oOther animals have the male deliver the sperm directly into the reproductive tracts of females so that fertilisation occurs inside the body – Internal Fertilisation.

Chapter 7 - Reproduction24 External Fertilisation in Animals

Chapter 7 - Reproduction25 Internal Fertilisation in Animals oOctopus p194 oInsects p195 oReptiles p195 oBirds p196 oMammals p196

Chapter 7 - Reproduction26 Internal Fertilisation in Animals o Quick Check Questions p198

Chapter 7 - Reproduction27 Meiosis – Making Gametes oGamete production involves the process of meiosis and, in animals, this process occurs in the testes for sperm production and in the ovaries for egg production. o Meiosis is the process by which one diploid (2n) cell with two sets of chromosomes produces four haploid (n) cells containing one set of chromosomes each. oAs well as halving the chromosome number, the process also reshuffles genes between pairs of chromosomes. Why?

Chapter 7 - Reproduction28 Meiosis – Making Gametes

Chapter 7 - Reproduction29 Meiosis – Making Gametes

Chapter 7 - Reproduction30 Meiosis – Making Gametes

Chapter 7 - Reproduction31 Meiosis – Making Gametes

Chapter 7 - Reproduction32 Meiosis – Making Gametes o Quick Check Questions p204

Chapter 7 - Reproduction33 Human Male Reproductive System

Chapter 7 - Reproduction34 Human Male Reproductive System

Chapter 7 - Reproduction35 Human Female Reproductive System

Chapter 7 - Reproduction36 Human Female Reproductive System

Chapter 7 - Reproduction37 The Menstrual Cycle o Quick Check Questions p209

Chapter 7 - Reproduction38 Reproduction Review o Biochallenge Questions 1-5 p210 o Chapter Review Questions 2-14 p