Biology 2e Chapter 43 Animal Development PDF

BIOLOGY 2E Chapter 43 Animal Development Lecture PowerPoint Slides This work is licensed under a Creative Commons Attribution-NonCommercial- ShareAlike 4.0 International License.  BIOLOGY 2E...

BIOLOGY 2E Chapter 43 Animal Development Lecture PowerPoint Slides This work is licensed under a Creative Commons Attribution-NonCommercial- ShareAlike 4.0 International License.  BIOLOGY 2E Chapter 43 Animal Development Lecture PowerPoint Slides Note: This PowerPoint includes textbook material from Sections 43.1, 43.2, 43.6, and 43.7 Sections 43.3 through 43.5 are not covered in this course. Some material from Sections 27.1 and 29.4 is also included. Some learning objectives are modified from those in the textbook.  CHAPTER 43 ANIMAL DEVELOPMENT 43.1 Reproduction methods and development 43.2 and 43.6 Fertilization and early embryonic development Also see textbook Section 27.1 43.7 Organogenesis and vertebrate embryos Also see textbook Section 29.4 Textbook sections 43.3 through 43.5 are not covered in this course.  43.1 REPRODUCTION METHODS AND DEVELOPMENT Learning Objectives By the end of this section, you will be able to do the following: Describe advantages and disadvantages of asexual and sexual reproduction Discuss sexual and asexual reproduction methods Explain the general process of development in animals  ASEXUAL REPRODUCTION Some animals usually reproduce asexually, but practice sexual reproduction on occasion Asexual reproduction produces genetically identical offspring and is advantageous in stable uniform environments.  SEXUAL REPRODUCTION Egg of one parent fertilized by sperm of another Produces genetically variable offspring. Advantageous in patchy, variable environments. Fertilization can be… external (e.g., fish, frogs); or internal (e.g., salamanders, reptiles, birds, mammals) Animals usually produce gametes in specialized organs called gonads Testes produce sperm Ovaries produce eggs SEXUAL REPRODUCTION Most animals are dioecious = separate sexes Egg of one parent is fertilized by sperm of another Some animals are monoecious (hermaphroditic) Contain both male and female sex organs in a single body Majority practice cross-fertilization with other individuals  DEVELOPMENT Development incudes all genetically-controlled changes in an individual organism from fertilization until death. Source: Wikipedia; Freepik; PsHere; Pexels; Flickr  DEVELOPMENT Sexually-reproducing animals all start from a fertilized egg (zygote). Tissues and organs develop from the zygote based on genetic instructions in the zygote DNA. Source: Wikipedia;  DEVELOPMENT Sexually-reproducing animals all start from a fertilized egg (zygote). Cell determination begins when certain genes are activated or inactivated as cells become gradually committed to a certain pathway. Cell differentiation results from cell determination, as gene regulation increasingly commits cells to their biochemical and structural forms. Source: Wikipedia;  DEVELOPMENT Sexually-reproducing animals all start from a fertilized egg (zygote). Organisms of different species end up with different morphology and physiology because of genetically-programed differences in development. Source: Wikipedia; Freepik; PsHere; Pexels; Flickr; Pexels; National Geographic  DEVELOPMENT And different individuals end up with different morphology and physiology because of genetically-programed differences in development. Source: Country Living Magazine; Human Evolution Blog  DEVELOPMENT The zygote DNA has all the genetic information to control the differentiation of cells during development. All the somatic cells in the body retain all this genetic information. Cells and tissues become differentiated because they express different genes at different times. Source: Wikipedia; Human Evolution Blog; Raptor Research Project  43.1 REPRODUCTION METHODS AND DEVELOPMENT Learning Objectives You should now be able to do the following: Describe advantages and disadvantages of asexual and sexual reproduction Discuss sexual and asexual reproduction methods Explain the general process of development in animals 43.2 AND 43.6 FERTILIZATION AND EARLY EMBRYONIC DEVELOPMENT Also see textbook Section 27.1 Learning Objectives By the end of this section, you will be able to do the following: Describe sperm morphology Discuss how fertilization occurs Discuss the role of cleavage and gastrulation in animal development  SPERM MORPHOLOGY Acrosome: organelle that contains enzymes that help penetrate egg Nucleus contains a random subset of the father’s nuclear DNA Mitochondrion: provides energy for the sperm (but the sperm mitochondrion does not enter the egg) Tail for movement Tail is an extension of the plasma membrane and cytoplasm Source: Wikimedia Commons  FERTILIZATION Sperm and egg fuse to form a zygote. Restores the diploid chromosome number Produces a new mixture of genetic information from both parents In many species, determines the sex of the offspring, based on genetic information on sex chromosomes Initiates the process of development (credit b: modification of work by Mariana Ruiz Villareal; scale-bar data from Matt Russell) This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  FERTILIZATION Egg membrane contains recognition proteins so the egg will be recognized by sperm from the same species. This is particularly necessary in animals with external fertilization The egg (or ovum) is often surrounded by outer layers that protect the egg and help ensure fertilization by only one sperm of the proper species Acrosomal enzymes in the sperm digest these layers Source: Wikimedia commons. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  DEVELOPMENT z ote celler blastula astrula embr o The embryo passes through several stages Cleavage Blastula Gastrula Neurula Organogenesis Source: Zendesk.com  DEVELOPMENT The details of animal development vary in different animal groups. The amount and distribution of yolk has an impact on the processes of development. Birds and reptiles have telolecithal eggs with a large amount of yolk taking up most of the egg. Amphibians have mesolecithal eggs with a moderate amount of yolk. Mammals and some invertebrates (such as sea urchins and starfish) have microlecithal eggs with minimal yolk. We will first discuss development in echinoderms (such as starfish and sea urchins), and then consider more complex adaptations in organisms with greater yolk. DEVELOPMENT IN ECHINODERMS Source: Wikipedia. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  CLEAVAGE IN ECHINODERMS During cleavage, the zygote rapidly divides by mitosis into multiple cells without increasing in size. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  ECHINODERM MORULA After several cell divisions, the embryo becomes a solid sphere of cells called a morula. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. ECHINODERM BLASTULA The cells of the morula rearrange themselves to form a hollow blastula, with a fluid-filled cavity called the blastocoel. (pronounced “Blast – Oh – Seal”) “coel” is a Greek root meaning “cavity.” You will see it in many anatomical terms for hollow spaces. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  GASTRULATION IN ECHINODERMS The blastula goes through the process of gastrulation to form the gastrula. The blastopore will become the first opening to the digestive tract. (Becomes the anus in vertebrates and echinoderms; the mouth in other invertebrates) Note that the blastopore is found in the gastrula, not in the blastula. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  GASTRULATION IN ECHINODERMS Gastrulation is the beginning of the digestive tract (the primitive gut or archenteron). It is also the beginning of the three germ layers (ectoderm, mesoderm, and endoderm) that will develop into specific tissues and organs in the adult animal. Archenteron Credit: Wikipedia. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. GERM LAYERS Cross section of a generalized animal embryo. Specific organs develop from each layer. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. DEVELOPMENTAL DIVERSITY We have seen the straightforward processes of development in representative microlecithal animals. In the next slides, we will see how these processes are modified in other animal groups that have more yolk. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. CLEAVAGE The cleavage we have seen in organisms with small amounts of evenly-distributed yolk is equal and holoblastic. Equal = the cells are approximately the same size. Holoblastic = the cells are completely separated from one another This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  CLEAVAGE IN AMPHIBIANS The smaller cells of the “animal pole” have little olk. The lar er cells of the “ve etal pole” have more olk. Amphibians have mesolecithal eggs with holoblastic but unequal cleavage. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  CLEAVAGE IN REPTILES AND BIRDS Telolecithal eggs of reptiles and birds have large amounts of yolk at the vegetal pole and a small amount of cytoplasm at the animal pole. The nucleus and cytoplasm are restricted to the germinal disc at the animal pole. The yolk never divides—cell division occurs in the germinal disc. Credit: Pineland Farms. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  CLEAVAGE IN REPTILES AND BIRDS Cleavage occurs only in the germinal disc. Reptiles and birds have meroblastic and unequal cleavage. Credit: Pineland Farms. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  GASTRULATION IN AMPHIBIANS In amphibians, large yolk-filled cells obstruct inward movement at the vegetal pole. Cells from the animal pole migrate inward from the dorsal lip to form the endoderm and mesoderm. Source: Wikipedia. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  GASTRULATION IN BIRDS In birds, development is restricted to the germinal disc. Cells of the epiblast migrate to the midline to form the primitive streak, the equivalent of the blastopore Cells then move inward to form the mesoderm and endoderm Source: Veterian Key. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. 43.2 AND 43.6 FERTILIZATION AND EARLY EMBRYONIC DEVELOPMENT Learning Objectives You should now be able to do the following: Describe sperm morphology Discuss how fertilization occurs Discuss the role of cleavage and gastrulation in animal development 43.7 ORGANOGENESIS AND VERTEBRATE EMBRYOS Learning Objectives By the end of this section, you will be able to do the following: Describe the processes of neurulation and organogenesis Describe the structure and function of the extraembryonic membranes of amniote vertebrates (see section 29.4 in textbook) NEURULATION The central region of the ectoderm forms the neural tube, which gives rise to the brain and the spinal cord. An embryo of this stage is called a neurula. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. PATTERN FORMATION AND MORPHOGENISIS During development, differentiated cells become progressively organized into a multicellular animal. – Morphogenesis proceeds through the process of pattern formation. These two have the same cell types but they are arranged in a different pattern Source: Veterian Key. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. PATTERN FORMATION AND MORPHOGENISIS Morphogenesis (shape / forming) Pattern formation locates cells in different regions with different signals (differentiation) Cells become progressively organized into different cell types, tissues, organs etc. Source: Veterian Key. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. ORGANOGENESIS Organogenesis is the development of organs and structures from the three original germ layers. Source: Veterian Key. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  GERM LAYERS (credit: modification of work by NIH, NCBI) This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  GERM LAYERS Ectoderm: Mesoderm: Endoderm: Skeleton Nervous system Inner lining of Muscles digestive tract Sense organs Circulatory system Inner lining of Outer skin layer Blood respiratory system (epidermis) Excretory system Liver and thyroid Nails, feathers, Reproductive system hair Inner skin layer (dermis) Muscular portion of digestive tract This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  EXTRAEMBRYONIC MEMBRANES Amniotes (reptiles, birds, and mammals) produce an amniote egg that keeps the embryo moist on dry land. The amniote egg contains extraembryonic membranes that surround and support the embryo Some of the extraembryonic membranes in mammals are modified to form the placenta, which connects the embryo to the mother and facilitates necessary transfer of oxygen, carbon dioxide, food, waste, and other substances between them. This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. EXTRAEMBRYONIC MEMBRANES Four membranes: chorion, amnion, allantois, and yolk sac – Chorion: (outermost membrane): encloses the entire embryo and other membranes; major organ of gas exchange – Amnion: encloses the embryo; secretes protective amniotic fluid that fills the amniotic cavity between the embryo and the amnion also acts as a shock absorber (amniotic fluid can be analyzed for biochemical or chromosomal abnormalities) This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  EXTRAEMBRYONIC MEMBRANES Four membranes: chorion, amnion, allantois, and yolk sac – Allantois: in reptiles and birds, it stores nitrogenous wastes; in mammals, its blood vessels contribute to the formation of umbilical vessels joining the embryo to the placenta – Yolk sac: encloses the yolk, slowly digests it, and makes it available to the embryo This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources. 43.7 ORGANOGENESIS AND VERTEBRATE EMBRYOS Learning Objectives You should now be able to do the following: Describe the processes of neurulation and organogenesis Describe the structure and function of the extraembryonic membranes of amniote vertebrates (see section 29.4 in textbook)