7. Jelly coatsIt prevents too many sperm from getting to the egg at the same time, because of its viscosity. Proteins in the jelly initiate the acrosome reaction in sperm so they are ready to fertilize the egg. It provides a sort of "shock absorber" to prevent injury .
8. Figure 32.1 Early es,mbryonic development (Layer 1) Cleavage is a series of rapid mitotic divisions (without cell growth)
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10. (d) Blastula. A single layer of cells surrounds a large blastocoel cavity. Although not visible here, the fertilization envelope is still present; the embryo will soon hatch from it and begin swimming. Four-cell stage. Remnants of the mitotic spindle can be seen between the two cells that have just completed the second cleavage division. (b) Morula. After further cleavage divisions, the embryo is a multicellular ball that is still surrounded by the fertilization envelope. The blastocoel cavity has begun to form. (c) Cleavage partitions the cytoplasm of one large cell Into many smaller cells called blastomeres Fertilized egg. Shown here is the zygote shortly before the first cleavage division, surrounded by the fertilization envelope. The nucleus is visible in the center. (a) Figure 47.7a–d
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16. SURFACE VIEW CROSS SECTION Animal pole 1 Gastrulation begins when a small indented crease, the dorsal lip of the blastopore, appears on one side of the blastula. The crease is formed by cells changing shape and pushing inward from the surface (invagination). Additional cells then roll inward over the dorsal lip (involution) and move into the interior, where they will form endoderm and mesoderm. Meanwhile, cells of the animal pole, the future ectoderm, change shape and begin spreading over the outer surface. Blastocoel Dorsal lip of blastopore Dorsal lip of blastopore Blastula Vegetal pole Archenteron Blastocoel shrinking The blastopore lip grows on both sides of the embryo, as more cells invaginate. When the sides of the lip meet, the blastopore forms a circle that becomes smaller as ectoderm spreads downward over the surface. Internally, continued involution expands the endoderm and mesoderm, and the archenteron begins to form; as a result, the blastocoel becomes smaller. 2 Ectoderm 3 Late in gastrulation, the endoderm-lined archenteron has completely replaced the blastocoel and the three germ layers are in place. The circular blastopore surrounds a plug of yolk-filled cells. Blastocoel remnant Mesoderm Endoderm Key Future ectoderm Future mesoderm Figure 47.12 Yolk plug Yolk plug Gastrula Future endoderm The mechanics of gastrulation in a frog
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18. Organogenesis Various regions of the three embryonic germ layers Develop into the rudiments of organs during the process of organogenesis
39. Chromosomes The DNA in every cell is located in rod like segments called chromosomes Chromosomes occurs in pairs in every cell of our body except in the sperm and ovum. Chromosomes numbers are the same for each specie.
41. Chromosomes There are 2 sex chromosomes included in the diploid number of the chromosomes. All of the other chromosomes are referred to as autosomes. In mammals if the sex chromosomes are alike, XX it results in a female. If the sex chromosomes are different, XY it results in a male.
42. Sex Determination Females contribute an X chromosome towards the sex of their offspring. Males can contribute an X or a Y chromosome toward the sex of their offspring. Absence of an Y chromosome results in a the embryo developing into a female. Presence of an Y chromosome results in the embryo developing into a male.
43. Sex Determination Gametogenesis = Formation of gametes through meiosis. Male = 4 viable spermatids Female = 1 viable ovum, 3 polar bodies.
53. F1 x F1 = F2 F2 possible gametes Punnett Square: t T Tall tt Tall TT T possible gametes Dwarf tt Tall Tt t Mendel as a Scientist Test Cross: Unknown Tall Dwarf x tt possible gametes If Unknown is TT: t t Tall Tt Tall Tt T possible gametes Test Progeny All Tall Tall Tt Tall Tt T 1/3 of F2 Tall are TT 2/3 of F2 Tall are Tt possible gametes If Unknown is Tt: t t Tall Tt Tall Tt T possible gametes Test Progeny Half Tall Half Dwarf Dwarf tt Dwarf tt t
54. Another Example of Mendel’s Work Green Yellow x Phenotype P gg GG Genotype Homozygous Recessive Homozygous Dominant All Yellow Clearly Yellow is Inherited… What happened to Green? F1 Gg Yellow is dominant to Green Use G/g rather than Y/y for symbolic logic Heterozygous F1 x F1 = F2 possible gametes NEVER use G/Y or g/y Punnett Square: g G 3/4 Yellow 1/4 Green F2 Yellow Gg Yellow GG G possible gametes Green gg Yellow Gg g Green is not missing…just masked as “recessive” in diploid state
55. F1 x F1 = F2 F2 possible gametes Punnett Square: g G Yellow Gg Yellow GG G possible gametes Green gg Yellow Gg g Mendel as a Scientist Test Cross: Unknown Yellow Green x gg possible gametes If Unknown is GG: g g Yellow Gg Yellow Gg G possible gametes Test Progeny All Yellow Yellow Gg Yellow Gg G 1/3 of F2 Yellow are GG 2/3 of F2 Yellow are Gg possible gametes If Unknown is Gg: g g Yellow Gg Yellow Gg G possible gametes Test Progeny Half Yellow Half Green Green gg Green gg g
67. In addition to this, there are multiple alleles possible: PR = red PY = yellow p = no pigment The combination of alleles in a diploid determine the flower color: PRPR = red PRPY = orange PYPY = yellow PRp = pink PYp = cream pp = white Human hair color follows a similar pattern: Alleles: HBn = brown HBd = blonde hR = red hbk = black The combinations of these alleles determine the base hair color: HBnHBn = dark brown HBnHBd = sandy brown HBnhR = auburn HBnhbk = dark brown HBdHBd = blonde HBdhR = strawberry blonde HBdhbk = blonde hRhR = red hRhbk = red hbkhbk = black Recessive can be common! Dominant does NOT mean frequent!
68. Another Example of Recessive Being Common: Pisum sativum Garden Peas: green seed, wrinkled seed, dwarf stature, white flower gg ww dd aa In other words: a quadruple double-recessive is the most common garden pea on Earth! Quantitative Inheritance: multiple genes control trait Highest Crop Yield: AABBCCDDEE Intermediate Crop Yield: AabbCCDdEe Lowest Crop Yield: aabbccddee Darkest Skin Color: AABBCCDDEE Intermediate Skin Color: AaBbCcDdEe Lightest Skin Color: aabbccddee AaBbCcDdEe x AaBbCcDdEe can produce a huge range of colors!
69. Phenotype = Genotype + Environment Crop Yield = Genotype + Minerals + Water + Light - Pests etc. Optimizing these factors determines agricultural productivity…last part of our course! Human Skin Color = Genotype + Sun (UV) Exposure - Aging Factors The sun exposure effect is most obvious in people of intermediate skin base color but everyone can have “tan lines.”
70. Who Gets To Mate With Whom? …Two Extremes Inbreeding Depression: related parents give same recessives to children Hemophilia: Queen Victoria’s Mutation and Diseased Grandchildren recessive sex-linked, X chromosome disorders, haemophilia is more likely to occur in males than females Tay-Sachs: Jewish Populations Recessive autosomal disease; relentless deterioration of mental and physical abilities Hybrid Vigor: Wild Corn A x Wild Corn B High Yield Hybrid Corn!
72. Continuous Variation Many traits may have a wide range of continuous values. Eg. Human height can vary considerably. There are not just "tall" or "short" humans
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74. Many biological pathways are governed by multiple enzymes, involving multiple steps. If any one of these steps are altered. The end product of the pathway may be disrupted.
78. What is an ecosystem? System= regularly interacting and interdependent components forming a unified whole Ecosystem = an ecological system;= a community and its physical environment treated together as a functional system
79. Ecosystem Services The human economy depends upon the services performed for free by ecosystems. The ecosystem services supplied annually are worth many trillions of dollars. Economic development that destroys habitats and impairs services can create costs to humanity over the long term that may greatly exceed the short-term economic benefits of the development. These costs are generally hidden from traditional economic accounting, but are nonetheless real and are usually borne by society at large. http://www.epa.gov/watertrain/pdf/issue2.pdf
81. Abiotic components: ABIOTIC components: Solar energy provides practically all the energy for ecosystems. Inorganic substances, e.g., sulfur, boron, tend to cycle through ecosystems. Organic compounds, such as proteins, carbohydrates, lipids, and other complex molecules, form a link between biotic and abiotic components of the system.
82. BIOTIC components The biotic components of an ecosystem can be classified according to their mode of energy acquisition. In this type of classification, there are: Autotrophs and Heterotrophs Organisms that produce their own food from an energy source, such as the sun, and inorganic compounds. Organisms that consume other organisms as a food source.
83. Trophic level: All the organisms that are the same number of food-chain steps from the primary source of energy Modified from: General Ecology, by David T. Krome
84. Trophic Levels A trophic level is the position occupied by an organism in a food chain. Trophic levels can be analyzed on an energy pyramid. Producers are found at the base of the pyramid and compromise the first trophic level. Primary consumers make up the second trophic level. Secondary consumers make up the third trophic level. Finally tertiary consumers make up the top trophic level.
85. Trophic Levels Found on an Energy Pyramid The greatest amount of energy is found at the base of the pyramid. The least amount of energy is found at top of the pyramid. Source: corpuschristiisd.org/user_files/91702/Ecosystem.ppt
86. Food Chains The producers, consumers, and decomposers of each ecosystem make up a food chain. There are many food chains in an ecosystem. Food chains show where energy is transferred and not who eats who.
90. Definition: Natural, gradual changes in the types of species that live in an area; can be primary or secondary The gradual replacement of one plant community by another through natural processes over time
91. Primary Succession Begins in a place without any soil Sides of volcanoes Landslides Flooding Starts with the arrival of living things such as lichens that do not need soil to survive Called PIONEER SPECIES
93. Primary Succession Soil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil
95. Primary Succession Simple plants like mosses and ferns can grow in the new soil http://www.uncw.edu http://uisstc.georgetown.edu
96. Primary Succession The simple plants die, adding more organic material The soil layer thickens, and grasses, wildflowers, and other plants begin to take over http://www.cwrl.utexas.edu
97. Primary Succession These plants die, and they add more nutrients to the soil Shrubs and tress can survive now http://www.rowan.edu
98. Primary Succession Insects, small birds, and mammals have begun to move in What was once bare rock now supports a variety of life http://p2-raw.greenpeace.org
99. Secondary Succession Begins in a place that already has soil and was once the home of living organisms Occurs faster and has different pioneer species than primary succession Example: after forest fires
101. Climax Community A stable group of plants and animals that is the end result of the successionprocess Does not always mean big trees Grasses in prairies Cacti in deserts
103. Symmetry Arrangement of parts with regard to the axes and planes. Way a body parts is arranged around a center point 4 fundamental types of animal symmetry: Spherical or universal Radial Biradial or radiobilateral Bilateral
104. Asymmetry Anaxial symmetry Body cannot be divided by planes into similar halves Body is irregularly shaped No definite anatomical relationship between different parts
106. Universal or Spherical Homoaxial symmetry Symmetry exists in an organism that can be dissected into equal or identical halves by any of the infinite axes and planes that transect it. Assumes shape of ball Body parts arranged concentrically around or radiating from a central point
108. Radial Symmetry Monoaxialheteropolar symmetry Organism assumes shape of a cylinder with parts arranged around and along a single central axis in which 2 ends are different: mouth and anus Central axis is referred as longitudinal, oral-aboral or antero-posterior axis. Plane passing through axis dividing organism into similar halves.
111. Bilateral Symmetry only the transverse axis has similar ends. Antero-posterior axis and dorso-ventral axis Divides animal into right and left with mirror images
113. Asymmetrical – without a balanced arrangement of similar parts on either side of a point or axis Radial - any plane passing through the oral-aboral axis divides an organism to mirror images Bilateral – only the midsagittal plane divides an organism to mirror images. Have definite anterior (head) and posterior (tail) ends
114. Other Features of animal Forms Antimeres – identical and asymmetrically corresponding parts of an animal. Arms of a starfish
115. Other Features of Animal Forms Metamerism – division of body into segments or metameres. Segmentation may be superficial or external (false) OR may include internal organs (true) Segments may be similar (homonomous) OR different from each other (heternomous)
116. Other Features of Animal Forms Cephalization – differentiation of anterior end of animal and is characterized by concentration of nervous elements such as formation of brain and sense organs. Well-developed head region
117. Other Features of Animal Forms Tagmatization or tagmosis – union of segments into larger functional groups. Each special group is a tagma (plural, tagmata)
123. Methods of Classification New Classification Carolus Linnaeus (1735) 2 main groups: Kingdom Use specific traits into same group and called it species Placed similar species to larger group called genus
128. How Scientists Classify Today Look at Traits Compare traits of one organism with those of another. Compare organisms living today with those that lived long ago.
130. Other Evidence Used in Classifying Based on living thing’s ancestors Horses and donkeys have many same ancestors Similar body structures Human and cat have similar front limbs and similar bones arranged in similar patterns Body chemistry Horseshoe crab’s blood is similar to spider
132. Why Scientific Names are Used No mistakes can be made about which living thing is described. Scientific names seldom change. Scientific names are written in the same language around the world.
135. Modern Classification Seven groups – Kingdom, phylum, class, order, family, genus, species Evidence – Same ancestors, similar body structure, body chemistry Organisms given 2-part scientific names Kingdoms – Moneran, Protist, Fungus, Plant, Animal
160. Why such rapid diversification? 1. Adaptive radiation 2. Predator-prey relationships 3. Higher concentration of oxygen
161. Porifera - Sponges No symmetry No organs The least complex animals Aquatic in fresh and marine environments
162. water out glasslike structural elements amoeboid cell pore semifluid matrix central cavity flattened surface cells water in flagellum microvilli nucleus Body Plan of a Sponge
164. Cnidaria Radial symmetry Body has only 2 cell layers Mouth surrounded by tentacles with stinging cells Aquatic, FW and marine Include jellyfish, corals, sea anemones, hydra Some are motile, and all have a very simple nervous system Respiration: direct gas exchange with aquatic surroundings
165. There are two Cnidarian body plans Polyp outer epithelium (epidermis) mesoglea (matrix) inner epithelium (gastrodermis) Medusa
166. reproductive polyp female medusa male medusa sperm ovum Life cycle of Obelia feeding polyp zygote planula polyp forming branching one branch from a mature colony
167. Flatworms - Platyhelminthes Body has 3 cell layers: ectoderm, mesoderm and endoderm Bilateral symmetry Parasitic and free -living aquatic (fw and marine) and terrestrial: tapeworms, flukes, and Planaria Digestive system with one opening Primitive nervous system Hermaphroditic Respiration through skin
168. pharynx (protruded) protonephridia flame cell nucleus cilia fluid filters through membrane folds Planaria, a free-living flatworm opening of tubule at body surface flame cell
170. b A definitive host eats infected, undercooked beef a Larvae become encysted in intermediate host tissues c Scolex of larva attaches to intestine’s wall d Many proglottids form by budding f Cattle may ingest embryonated eggs or ripe proglottids to become intermediate hosts e Ripe proglottids containing fertilized eggs leave host in feces Tapeworm life cycle
171. Roundworms - Nematoda Digestive system with mouth and anus (“complete”) Separate sexes Aquatic and terrestrial, free living and parasitic Body cavity gives “tube within a tube” construction Respiration through skin, no circulatory system
172. Body Plan of a Roundworm gonad pharynx intestine eggs in uterus anus false coelom muscularized body wall Caenorhabditiselegans
174. Mollusks - Mollusca Often but not always have external shell Includes clams, oysters, snails, slugs, squid, octopus, scallops, chambered nautilus Body is soft with bilateral symmetry Nervous system, circulatory system, respiratory system Some have excellent sense organs and large brains, and can learn easily.
175. Body Plan of a Snail anus gill mantle cavity excretory organ heart digestive gland shell stomach mantle radula foot
176. Body Plan of a Cuttlefish esophagus stomach kidney digestive gland brain arm jaw mantle reproductive organ internal shell siphon ink sac heart accessory heart tentacle radula anus gill
177. Segmented Worms - Annelida Body composed of many identical segments. Allows more specialization Aquatic or terrestrial Includes clam worm, feather worms, leeches, and earthworm. These animals have “all” systems, and are quite complex. They are most likely the ancestors of the Arthropods, the most successful Phylum of animals on Earth.
184. Both words are italicized if typed or underlined if hand written. Example: Felis concolor or F. concolor Which is the genus? The species? Binomial Nomenclature
185. "Formal" scientific names should have a third part, the authority. The authority is not italicized or underlined. The authority is written as an abbreviation of the last name of the person responsible for naming the organism. Since Carolus Linnaeus was the first person to name many plants, the L. for Linnaeus is very common in plant scientific names. An example is Quercus alba L.
Editor's Notes
Amphioxus-cephalochordata
Tay-Sachs disease, it causes a relentless deterioration of mental and physical abilities that commences around six months of age and usually results in death by the age of four