bio exam 4
choanoflagellates
Name the closest living relative to animals
Protostomes (mouth develops before anus) are bilaterally symmetric and triploblastic (made of endoderm, mesoderm, and ectoderm)....Two monophyletic groups of protostomes are called the Lophotrochozoa and Ecydysozoa. -Lophotrochozoa includes mollusks, annelids, and flatworms. -Ecydysozoa includes roundworms and arthropods.
Name the major phyla of protostomes that we discussed - the mollusks, annelids and arthropods, roundworms and flatworms; and state which is the most abundant. and state which group-the lophotrochozoans or the ecdysozoans- each belongs to.
cephalization: The formation of a distinct anterior region (the head) where sense organs and a mouth are clustered. The large mass of neurons that is located in the head, and that is responsible for processing information from throughout the body, is called the cerebral ganglion or BRAIN. In combination with the origin of mesoderm, a bilaterally symmetric body plan enabled rapid, directed movement and hunting.
describe cephalization and its importance and how it is associated with bilateral symmetry
Species that have a flagellum with hollow, hairlike projections. This synamorphy identifies their major monophyletic group. The species that caused the Irish potato famine are stramenopiles
stramenopiles
-They are multicellular, will cells that lack cell walls but have an extensive extracellular matrix. The ECM includes proteins specialized for cell-cell adhesion and communication. -They are heterotrophs, meaning that they obtain the carbon compounds they need from other organisms. Most ingest their food, rather than absorbing it across the body surface. All animals move under their own power at some point in their life cycle, and all animals other than sponges have: (1) specialized cells called neurons-nerve cells-that transmit electrical signals to other cells; and (2) muscle cells that can change the shape of the body by contracting. In most animals, neurons connect to each other, forming a nervous system, and some neurons connect to muscle cells- which may contract in response to electrical signals from neurons. Muscles and neurons allow a large multicellular body to move efficiently.
traits that all animals share.
(1) a nucleus and endomembrane system, (2) mitochondria or genes that are normally found in mitochondria, and (3) a cytoskeleton.
All eukaryotes alive today have:
single-celled organisms with a nucleus and endomembrane system, mitochondria, and a cytoskeleton, but no cell wall.
Biologists hypothesize that the earliest eukaryotes were probably:
The origin and early evolution of animals was based on four aspects of the fundamental architecture, or BODY PLAN, of animals: (1) the origin and elaboration of tissues- especially the tissues found in embryos; (2) the origin and elaboration of the nervous system and the subsequent evolution of a cephalized body- one with a distinctive head region (3) the evolution of a fluid-filled body cavity (4) variation in the events of early embryonic development. tissues: a group of similar cells that function as a unit, such as muscle tissue or epithelial tissue. epithelium- a layer of tightly joined cells that covers the surface. Diploblasts: ("two-buds") animals whose embryos have two types of tissue. Body develops from two basic embryonic cell layers- ectoderm and endoderm. Triploblasts: ("three-buds") animals whose embryos have three types. Body develops from three basic embryonic cell layers- ectoderm, mesoderm, and endoderm.
Comparitive morphology -Describe of the fundamental aspects of the body plan of animals including: -tissues -distinguish between diploblasts and triploblasts.
If the major animal lineages are defined by a particular body plan, what triggered the diversification of species within each lineage? In most cases, the answer to this question is the evolution of innovative methods for sensing the environment, feeding, and moving. VARIATION IN SENSORY ABILITIES: the common senses include touch and balance- meaning animals can sense objects and gravity- along with sense of smell, taste, and hearing. Ability to sense light and time is also common. As animals diversified, a wide array of more specialized sensory abilities evolved.. magnetism: many birds, sea turtles, sea slugs, and other animals can detect magnetic fields and use earth's magnetic field as an aid in navigation. electric fields: some aquatic predators, such as sharks, are so sensitive to electric fields that they can detect electrical activity in the muscles of passing prey. barometric pressure: some birds can sense changes in air pressure, which may aid them in avoiding storms. Animals can sense different aspects of the environment because they have different sensory structures.
Describe diversification of animal species including the evolution of innovative methods for; - sensing the environment -feeding
Biologists distinguish how individuals eat from what they eat. How can animals from the same lineage have the same basic body architecture but feel in different ways? (1) their mouthparts vary, (2) the structure of an animal's mouthparts correlates closely with its method of feeding. SUSPENSION FEEDERS: (filter feeders) capture food by filtering out or concentrating particles floating in water or drifting through the air. (particularly common in aquatic environments. Many suspension feeders are sessile) DEPOSIT FEEDERS: ingest organic material that has been deposited within a substrate or on its surface. Many deposit feeders digest organic matter in the soil. Food consists of soil-dwelling bacteria, archaea, protists, and fungi, along with detritus that settles on the surface of the soil. Seafloor is also rich in organic matter. Deposit feeders are similar in appearance. Usually have simple mouthparts and body shape is wormlike. FLUID FEEDERS: suck or mop up liquids like nectar, plant sap, blood, or fruit juice. Use a sponge-like mouthpart. Found in a wide array of lineages and often have mouthparts that allow them to pierce seeds, stems, skin, or other structures to withdraw fluids inside. MASS FEEDERS: take chunks of food into their mouths. Structure of mouthparts correlates with type of food pieces that are harvested and ingested.
Describe diversification of animal species including the evolution of innovative methods for; -feeding differentiate between suspension feeders, deposit feeders, fluid feeders, mass feeders.
Cephalopods (squid and octopus) are mollusks that have a mantle lined with muscle. When the cavity surrounded by the mantle fills with water and the mantle muscles contract, a stream of water is forced out of a tube called a siphon. The force of the water propels the squid. This mechanism, jet propulsion, evolved in squid long before human engineers thought of using the same principle to power aircraft.
Describe movement by jet propulsion.
All protostomes are triploblasic and bilaterally symmetric and all protostomes undergo embryonic development in a similar way. In wormlike phyla, the coelom is well developed and functions as a hydrostatic skeleton that is the basis of movement. Coelom is absent in flatworms, and in most species-rich an morphologically complex protostome phyla- the Arthropoda and the Mollusca (snails, clams, squid)- it is drastically reduced. They do not need a fully functioning coelom. Arthropods have segmented bodies that are organized into prominent regions called TAGMATA. These regions are the head, thorax, and abdomen. In addition, arthropods are distinguished by their jointed limbs and an exoskeleton make primarily of the polysaccharide chitlin. In crustaceans, the exoskeleton is strengthened by the addition of calcium carbonate (CaCO3). Instead of being based on muscle contraction against a hydroskeleton, arthropod locomotion is based on muscles that apply force against the exoskeleton to move legs or wings. Arthropods also have a spacious body cavity called the HEMOCOEL ("blood-hollow") that provides space for internal organs and circulation of fluids. In addition, the hemocoel functions as a hydrostatic skeleton in caterpillars and other types of arthropod larva.
Describe the body plans and the major structures and their functions of the; arthropods
The body plan of mollusks is based on three major components: (1) the foot: a large muscle located at the base of the animal and usually used in movement (2) the visceral mass: the region containing most of the main internal organs; and (3) the mantle: an outgrowth of the body wall that covers the visceral mass, forming an enclosure called the mantle cavity. Visceral mass provides space for organs and the circulation of fluids. In some species the fluid enclosed by the visceral mass also functions in movement as a hydrostatic skeleton. In many species the mantle secretes a shell made of calcium carbonate.
Describe the body plans and the major structures and their functions of the; mollusks
In many cases the wormlike lineages are distinguished by specialized mouthparts or feeding structures. Annelids (segmented worms): Annelids include a group called the echiurans or spoon worms, which burrow into marine mud. Echiurans deposit feed using an extended structure called a probiscis, which forms a cutter leading to the mouth. Cells in the cutter secrete mucus, which is sticky enough to capture pieces of detritus. The combination of mucus and detritus is then swept into the mouth by cilia on cells in the gutter. Priapulids (penis worms): Priapulids also burrow into the substrate, but act as sit-and-wait predators. When a polychaete (Annelida) or other prey item approaches, the priapulid everts its toothed, cuticle-lined throat- meaning that it turns its throat inside out- grabs the prey item, and retracts the structure to take in the food. Nemerteans (ribbon worms): Active predators that move around the ocean floor in search of food. Instead of everting their throat to capture prey, they have a proboscis that can extend or retract. Nemerteans spear small animals with their proboscis or wrap the extended proboscis around prey, then pull food into the mouth.
Describe the body plans and the major structures and their functions of the; worm-like protostomes annelids priapulids nemerteans
Protist- Any eukaryote that is not a green plant, animal, or fungus. Protists are a diverse paraphyletic group. Most are unicellular, but some are multicellular or form aggregations called colonies.; Protists do not make up a monophyletic group. They refer to a paraphyletic group- represent some, but not all, descendants of a single common ancestor. WHAT THEY ALL HAVE IN COMMON: tend to live in environments where they're surrounded by water. Most plants, fungi, and animals are terrestrial, but protists are found in wet soils, aquatic habitats, or the bodies of other organisms-including humans.
Describe the characteristics of protists, including what all protists have in common.
amoeboid motion: A form of cellular movement involving actin filaments in which the cell produces bulges (pseudopodia "false feet") that stick to the substrate and pull the cell forward. Requires ATP and involves interactions between proteins called actin and myosin in the cytoplasm. Flagella and cilia both consist of nine sets of doublet (paired) microtubules arranged around two central, single microtubules. Flagella are long and are usually found alone or in pairs; cilia are short and usually occur in large numbers on any one cell. Ciliates swim by beating their cilia, dinoflagellates swim by whipping their flagella, and mature cells in apicomplexa move by amoeboid motion (though their gametes swim via flagella)
Describe the different methods of protist locomotion including; amoeboid motion, flagella, cilia.
-The nuclear envelope is a synapomorphy that defines the Eukarya. -Compared to bacteria and archaea, most eukaryotic cells are large, have many more organelles, and have a much more extensive system of structural proteins called the cytoskeleton. -Multicellularity is rare in bacteria and unknown in archaea, but has evolved multiple times in eukaryotes. -Bacteria and archaea reproduce asexually by fission; many eukaryotes reproduce asexually via mitosis. -Many eukaryotes undergo meiosis and reproduce sexually.
Describe the fundamental features of eukaryotes that distinguish them from bacteria and archaea.
Embryonic tissues are organized in layers, called GERM LAYERS. Diploblasts: germ layers are called ectoderm (outer) and endoderm (inner). Triploblasts: germ layers are called ectoderm, mesoderm (middle) and endoderm. Embryonic tissues found in animals develop into distinct adult tissues, organs, and organ systems. In triploblasts: -ectoderm--> skin and nervous system -endoderm--> lining of the digestive tract -mesoderm--> circulatory system, muscle, and internal structures such as bone and most organs. In general, ectoderm produces covering of the animal and endoderm generates digestive tract. Mesoderm is tissues in between. In diploblasts, (1) muscle is sumpler in organization and is derived from ectoderm and (2) reproductive tissues are derived from endoderm.
Describe the germ layers and what each gives rise to.
HARMFUL ALGAL BLOOMS: Usually due to photosynthetic protists called dinoflagellates. Certain dinoflagellates synthesize toxins to protect themselves from predation by small animals called copepods. Because toxin-producing dinoflagellates have high concentrations of accessory pigments called xanthophylls, their blooms can sometimes discolor seawater. ALGAL BLOOMS CAN BE HARMFUL TO PEOPLE BECAUSE clams and other shellfish filter photosynthetic protists out of the water as food. During a bloom, high levels of toxins can build up in the flesh of these shellfish. If a person eats contaminated shellfish, several types of poisoning can result.
Describe the impact of protists on: Human health and welfare including their role (and the specific protist involved) in the; Potato Famine in Ireland Malaria Harmful algal blooms
MALARIA: caused by a protists in the lineage called Apicomplexa. Ranks as world's most chronic public health problem. over 1 mill die annually. most are preschool age. 4 species of Plasmodium can parasitize humans. [primarily P. falciparum and P. vivax] Infections start when Plasmodium cells enter a person's bloodstream during a mosquito bite. Plasmodium initially infects liver cells; later, some Plasmodium cells change into a distinctive cell type that infects the host's red blood cells. Plasmodium cells multiply inside host cells, which are killed as parasite cells exit to infect additional liver cells or red blood cells.
Describe the impact of protists on: Human health and welfare including their role (and the specific protist involved) in the; Potato Famine in Ireland Malaria Harmful algal blooms
POTATO FAMINE: In 1845 most of the 3 million acres that had been planted to grow potatoes in Ireland became infested with *Phytophthora infestans*- a parasite that belonds to a lineage of protists called Oomycota. Potato tubers that were infected with P. infestans rotted. Crops failed for 2 consecutive years, 1 mill. people died of starvation or starvation related illnesses.
Describe the impact of protists on: Human health and welfare including their role (and the specific protist involved) in the; Potato Famine in Ireland Malaria Harmful algal blooms
At least some species in most animal phyla can reproduce asexually, through mitosis, as well as sexually (via meiosis and fusion of gametes) Internal fertilization: males typically insert a sperm-transfer organ into the body of a female. In some cases, males produce sperm in packets, which females then pick up and insert into their own bodies. In seahorses, females insert eggs into the male's body, where they are fertilized. External fertilization: extremely common in aquatic species. Females lay eggs onto a substrate or into open water. Males shed sperm, which swim, on or near the eggs.
Describe the methods of reproduction including; sexual vs asexual external vs internal fertilization
THE NUCLEAR ENVELOPE: The leading hypothesis to explain the origin of the nuclear envelope is based on infoldings of the plasma membrane. Step-wise process could give rise to small infoldings that were elaborated by mutation and natural selection over time, with the infolding eventually becoming detached from the plasma membrane. Infoldings would have given rise to the nuclear envelope and the endoplasmic reticulum (ER) together. ADVANTAGEOUS BECAUSE: it separated transcription and translation (RNA transcripts inside nucleus but translated outside nucleus). An important morphological innovation gave the early eukaryotes a new way to manage and process genetic info.
Describe the morphological innovations that evolved in protists including; -The nuclear envelope. -Structures for support and protection. pg. 528 - Multicellularity. pg. 529
desmosomes: specialized junctions that hold adjacent cell together, consist of dense plate at point of adhesion plus extracellular cementing material. gap junction: type of cell-cell attachment structure that directly connects the cytoplasms of adjacent animals cells, allowing passage of water, ions, and small molecules between the cells. tight junction: type of cell-cell attachment structure that links the plasma membranes of adjacent animal cells, forming a barrier that restricts movement of substances in the space between the cells. Most abundant in epithelia (e.g., the intestinal lining.)
Describe the structure and functions of gap junctions, tight junctions, and desmosomes.
The basic animal body is a tube within a tube. The inner tube is the individual's gut, and the outer tube forms the body wall. The mesoderm in between forms muscles and organs. Wings and legs are just efficient ways to move a tube-within-a-tube body around the environment.
Describe the tube within a tube design and its importance
When ingestive feeding occurs, an individual takes in packets of food much larger than individual molecules. This, protists feed by (1) ingesting packets of food, (2) absorbing organic molecules directly from the environment, or (3) performing photosynthesis. ingestive feeding: feeding by engulfing is possible in protists that lack a cell wall. A flexible membrane and dynamic cytoskeleton allow species to surround and "swallow" prey using fingerlike projections called pseudopodia ("false-feet") absorptive feeding: occurs when nutrients are taken up directly from the environment, across the plasma membrane. Absorptive feeding is common among protists. Some protists that live by absorptive feeding are decomposers, meaning they feed on dead organic matter or detritus. Many of the protists that absorb their nutrition directly from the environment live inside other organisms. If they damage their host, the absorptive species is called a parasite. PHOTOSYNTHESIS: endysymbiosis and the origin of the chloroplast; They "stole" it. The endosymbiosis theory contends that the eukaryotic chloroplast originated when a protist engulfed a cyanobacterium. Once inside the protist, the photosynthetic bacterium provided its eukaryotic host with oxygen and glucose in exchange for protection and access to light. Chloroplasts trace their ancestry to cyanobacteria. SECONDARY ENDOSYMBIOSIS occurs when an organism engulfs a photosynthetic eukaryotic cell and retains its chloroplasts as intracellular symbionts.
Different methods that protists use to obtain food including; ingestive feeding, absorptive feeding, photosynthesis
endosymbiosis theory: The theory that mitochondria and chloroplasts evolved from prokaryotes that were engulfed by host cells and took up a symbiotic existence within those cells, a process termed primary endosymbiosis. In some eukaryotes, chloroplasts originated by secondary endosymbiosis, that is, by engulfing a chloroplast-containing protist and retaining its chloroplasts. symbiosis: Any close and prolonged physical relationship between individuals of two different species. symbiosis is said to occur when individuals of two different species live in physical contact; endosymbiosis occurs when an organism of one species lives inside an organism of another species.
Differentiate between symbiosis and ensosymbiosis
Nerve nets and CNS's are associated with two contrasting types of body symmetry: radial (literally "spoke") or bilateral ("two sides"). Cnidarians and ctenophores, along with many sponges, have radial symmetry-meaning they have at least 2 planes of symmetry. Many radially symmetric animals either float in water or live attached to a substrate. Organisms with bilateral symmetry, have one plane of symmetry and tend to have a long, narrow body. The earthworm only has one plane of symmetry-running lengthwise down its middle. RADIALLY SYMMETRIC ORGANISMS are equally likely to encounter prey and other aspects of the environment in any direction. As a result, a diffuse nerve net can receive and send signals efficiently. BILATERALLY SYMMETRIC ORGANISMS tend to encounter prey and other aspects of the environment at one end. As a result it is advantageous to have many neurons concentrated at that end, with nerve tracts that carry info from there down the length of the body.
Discuss bilateral and radial symmetry and how they are related to the nervous system
METAMORPHOSIS: ("change-form") a change from an immature body type to an adult body type. LARVAE: look radically different from adults, live in different habitats, and eat different foods. They are sexually immature, meaning that their reproductive organs are undeveloped. JUVENILES: look like adults and live in the same habitats and eat the same foods as adults, but are sexually immature. ADULTS: are the reproductive stage in the life cycle.
Discuss metamorphosis including; distinguishing between -larvae, juveniles, adults
Food: humans depend on wild and domesticated animals for food. Materials: fibers used to make clothing, blankets, and other articles, as well as leather used in shoe-making and other industries. Transportation: preindustrial societies; source of transportation and power. Horses, donkeys, oxen, etc. transport people, cargo, and do work. Disease transmission: mosquitoes-malaria. rats- earlier centuries carried bacterium responsible for deadly bubonic plague. Model organisms: Humans are animals so efforts to understand human biology depend on advances in animal biology. -humans share a large portion of their genome with other animals. As a result, research on animals like fruit flies and zebrafish has revealed fundamental aspects of cellular and developmental bio that are shared by humans. -because genetic homologies between humans and other animals are so extensive, most drug testing and other types of biomedical research can be done on mice, rats, or primates instead of humans.
Discuss the roles of animals in human health and welfare including; food, materials, and transportation disease transmission model organisms
ASEXUAL REPRODUCTION: FRAGMENTATION- splitting the body lengthwise or by "fragmenting" the body is common in many of the wormlike phyla. PARTHENOGENESIS- ("virgin-origin")- many crustacean and insect species reproduce by producing unfertilized eggs, by mitosis, that develop into offspring. SEXUAL REPRODUCTION -often based on external fertilization in clams, bryozoans, brachiopods, and other groups. -often begins with copulation and internal fertilization in groups that are capable of movement- such as crustaceans, snails, and insects- because males and females can meet.
Discuss the various preproduction methods of protostomes including; asexual fragmentation parthenogenesis sexual external fertilization internal fertilization
LOPHOTROCHOZOAN: 12 phyla, including mollusks, annelids, and flatworms. Morphological traits that are found in some, but not all, of the phyla in the lineage: (1) feeding structure called a lophophore, which is found in three phyla; and (2) a type of larva called a trochophore, which is common to many of the phyla in the lineage. LOPHOPHORE: ("tuft-bearer") is a specialized structure that rings the mouth and functions in suspension feeding. Lophophores are found in bryozoans (moss animals), brachiopods (lamp shells, and phoronids (horseshoe worms_ TROCHOPHORES: ("wheel-bearer") are a type of larvae common to marine mollusks, annelids that live in the ocean, and several other phyla in the Lophotrochozoa. A trochophore has a ring of cilia around its middle. These cilia allow swimming and in some species sweep food particles into the mouth. Recent analyses are suggesting the the trochophore originated early in the evolution of Lophotrochozoans. Neither lophophores nor trochophores qualify as a synapomorphy in Lophotrochozoa, however. Ecdysozoa are defined by a clear synapomorphy: their method of growth. Like other animals, lophotrochozoans grow continuously and incrementally. But ecdysozoans to not. ECDYSOZOAN: Grow by molting- shedding an exoskeleton or external covering. During a molt, an individual sheds its outer later, or cuticle- called en exoskeleton if it is hard- and slips out of it. Once the old covering is gone, the body expands and a larger cuticle or exoskeleton then forms. A stiff body covering is advantageous because it provides an effective structure for muscle attachment and affords protection. After a molt, it takes hours for their new exoskeleton to harden which leaves them vulnerable.
Distinguish between the lophotrochozoans (these include the mollusks, annelids and flatworms) and the ecdysozoans (includes the roundworms and the arthropods). Describe the distinguishing morphological traits of lophotrochozoans including; lophophores trochophores
Bilateria: Major lineage of animals that are bilaterally symmetrical at some point in their life cycle, have three embryonic germ layers (are triploblasts) and have a coelom. All PROTOSTOMES and DEUTEROSTOMES are bilaterians. Based on distinctive events that occur early in the development of the embryo, the bilaterians can be split into two subgroups: PROTOSTOMES: ("first-mouth") in which the mouth develops before the anus, and blocks of mesoderm hollow out to form the coelom DEUTEROSTOMES: ("second-mouth") in which the anus develops before the mouth and pockets of mesoderm pinch off to form the coelom.
Distinguish between the protostomes and deuterostomes including their patterns of development;
Although species diversity of protists may be relatively low, their abundance is extraordinarily high. Why is this important... PROTISTS PLAY KEY ROLE IN AQUATIC FOOD CHAINS: Primary producers create their own food by photosynthesis or from reduced inorganic compounds and are a food source for other species in their ecosystem. Diatoms, for example, are photosynthetic protists that rank among the leading primary producers in the ocean. Diatoms and other small organisms that live near the surface of oceans or lakes are called plankton. the sugars and other organic compounds produced by photosynthetic plankton are the basis of food chains in freshwater and marine environments.
Ecological importance of protists
Mitochondria evolved through a series of steps, beginning with a eukaryotic cell that was capable only of anaerobic fermentation- could not use oxygen as an electron acceptor in cellular respiration. 1. The eukaryotic cell used its cytoskeletal elements to surround and engulf smaller prey. 2. Instead of fusing with a lysosome and being digested, an engulfed bacterium began to live inside a eukaryotic cell. 3. The engulfed cell survived by absorbing carbon molecules with high potential energy from the eukaryotic cell and oxidizing them, using oxygen as a final electron acceptor. BENEFITS TO BACTERIUM: host supplied it protection and carbon compounds from its other pray BENEFITS TO HOST CELL: bacterium produced much more ATP than the host cell could synthesize on its own. STRUCTURE OF MITOCHONDRIA CONSISTENT WITH ENDOSYMBIOSIS THEORY: -mitochondria are about the size of an average a-proteobacterium. -mitochondria replicate by fission, as to bacterial cells. The duplication of mitochondria takes place independently of division by the host cell. When eukaryotic cells divide, each daughter cell receives some of the many mitochondria present. -Mitochondria have their own ribosomes and manufacture their own proteins. Mitochondrial ribosomes closely resemble bacterial ribosomes in size and composition and are poisoned by antibiotics such as streptomycin that inhibit bacterial, but not eukaryotic, ribosomes. -mitochondria have double membranes, consistent with the engulfing mechanism of origin -mitochondria have their own genomes, which are organized as circular molecules, much like a bacterial chromosome. Mitochondrial genes code for the enzymes needed to replicate and transcribe the mitochondrial genome.
Endosymbiosis theory of the origin of the mitochondria including: how it occurred and what it resulted in. the benefits to the host cell and to the bacterium. the characteristics of mitochondria are consistent with it.
-Asexual reproduction is based on mitosis in eukaryotic organisms and on fission in bacteria and archaea. It results in offspring that are genetically identical to the parent. -Sexual reproduction is based on meiosis and fusion of gametes. It results in offspring that are genetically different from parents and each other. Most protists undergo asexual reproduction routinely. Sexual rep. occurs intermittently in many protists- often at one time of year or when individuals are crowded or food is scarce. Many biologists view sexual reproduction as an adaption to fight disease.
Methods of protist reproduction including asexual and sexual.
NERVE NET: A nervous system in which neurons are diffuse instead of being clustered into large masses or tracts. Cnidarians and ctenophores have nerve cells organized in this way. CENTRAL NERVOUS SYSTEM: (the brain and spinal cord of vertebrate animals) All other animals have a CNS. Some neurons are clustered into one or more large tracts or cords that project throughout the body; others are clustered into masses called ganglia.
Nervous System: distinguish between a nerve net and a central nervous system.
Protostomes have such a wide variety of mouthparts for capturing and processing food. Arthropods have the most diverse mouthparts. All arthropods have the same basic body plan but their mouthparts and food sources are highly diverse. Jointed limbs also pay a role in getting food. They can use their legs to sweep food toward their mouths. They can use their appendages to capture prey or hold good as it is being chewed or bitten.
Regarding transition from water to land, describe the adaptations of protostomes for; feeding
To make the transition to land, new adaptations allowed protostomes to (1) exchange gases and (2) avoid drying out. Land animals exchange gases with the atmosphere readily as long as a large, moist surface area is exposed to the air. The bigger challenge is to prevent the gas exchange surface and other parts of the body from drying out. How do terrestrial protostomes solve this problem? -Roundworms and earthworms live in humid soils or other moist environments and exchange gases across their body surface. They have a high surface-area-to-volume ratio, which increases the efficiency of gas exchange. -Arthropods and many mollusks have gills or other respiratory structures located inside the body. This location minimized water loss when certain groups moved onto land. -In mollusks, the mantle cavity that encloses the gills of aquatic snails evolved into the lung found in terrestrial snails. -Insects evolved a waxy layer to minimize water loss from the body surface, with openings to respiratory passages that can be closed if the environment dries.
Regarding transition from water to land, describe the adaptations of protostomes for; gas exchange feeding moving
As arthropods diversified, a number of important evolutionary innovations allowed them to move in unique ways: -jointed limbs in arthropods made rapid, precise walking, jumping, and jumping movements possible. -insect wing. about 2/3 of the multicellular species living today are winged insects. In many cases, larvae lack wings and crawl or swim. Insects were the first organisms that had wings and could fly. -the mollusk foot: snails and chitons are mollusks that have a muscular foot at the base of the body. Waves of muscle contractions sweep up or down the length of the large, muscular foot, allowing individuals to crawl along a surface.
Regarding transition from water to land, describe the adaptations of protostomes for; moving
...
State which protostomes lack neurons, which have nerve networks, and which have central nervous systems.
(1) important medically (2) important ecologically (3) critical to understanding the evolutions of plants, fungi, and animals
Why do biologists study protists?
Coelom: an internal, usually fluid-filled, body cavity that is lined with mesoderm. The coelom creates a container for the circulation of oxygen and nutrients, along with space where internal organs can move independently of each other. Although cnidarians and ctenophores have a central canal that functions in digestion and circulation, they do not have a coelom. The handful of triploblasts that do not have a coelom are called acoelomates ("no-cavity-form") The coelom was a critically important innovation during animal evolution because an enclosed, fluid-filled chamber can act as an efficient hydrostatic skeleton. Soft bodied animals with hydrostatic skeletons can move effectively even if they do not have fins or limbs. Roundworms use this to move. Fluid inside coelom stretches the body wall-much like a water balloon-meaning it's under tension. Force exerts pressure on the fluid inside the coelom. When muscles in the body wall contract against the pressurized fluid, the force is transmitted through the fluid, changing the body's shape. hydrostatic skeleton: A system of body support involving fluid-filled compartments that can change in shape but cannot easily be compressed.
body cavity evolution Describe the structure and functions of the coelom including explaining how hydrostatic skeletons function.
Where do embryos develop? VIVIPAROUS: (live-bearing) mammals and other species that nourish embryos inside the body and give birth to live young. OVIPAROUS: (egg-bearing) species that deposit fertilized eggs. OVOVIVIPAROUS: (egg-live-bearing) females retain eggs inside their body during early development; but the growing embryos are nourished by yolk inside the egg and not by nutrients transferred directly from the mother, as in viviparous species. Ovoviviparous females then give birth to well-developed young.
differentiate between viviparous species, oviparous species and ovoviviparous species
Animal locomotion has an array of important functions: finding food, finding mates, escaping from predators, and dispersing to new habitats. Burrow, slither, swim, fly, crawl, walk, or run. Movement is powered by cilia, flagella, or muscles that attach to a hard skeleton or compress a hydrostatic skeleton, enabling wriggling movements. TYPES OF LIMBS: unjointed (lobe-like) and jointed. Limbs are particularly important in two major lineages: ecdysozoans and vertebrates. Jointed limbs make fast, precise movements possible and are a prominent limb type in vertebrates and arthropods. Distal-less (Dll) is a protein which delivers the message "grow appendage out this way". Involved in limb formation.
discuss the various methods of animal movement and the structures involved
acoelomates: no coelom "no-cavity-form" coelomates: posess a coelom
distinguish between acoelomates and coelomates
HEMIMETABOLOUS ("half-change") metamorphosis: also called incomplete metamorphosis-- young are juveniles called nymphs that look like miniature versions of the adult. They shed their external skeletons several times and grow-gradually changing from wingless, sexually immature nymphs to sexually mature adults, some of which can fly. But throughout their life, they live in the same habitats and feed on the same food source in the same way. HOMOMETABOLOUS ("whole change") metamorphosis: also called complete metamorphosis-- young are larvae. For example: mosquitoes.. -newly hatches mosquitoes live in quiet bodies of freshwater, where they suspension feed on bacteria, algae, and detritus. -when a larva has grown sufficiently, the individual stops feeding and moving and secretes a protective case. The individual is now known as a pupa. During pupation, the pupa's body is completely remodeled into a new, adult form. -the adult mosquito flies and gets its nutrition as a parasite- taking blood meals from mammals and nectar from flowers.
distinguish between hemimetabolous metamorphosis and holometabous metamorphosis
Herbivores: feed on plants or algae Carnivores: feed on animals Detritivores: feed on dead organic matter Omnivores: Animals that eat both plants and animals Herbivores and carnivores can be subclassified as (1) predators or (2) parasites. Predators: are usually larger than their prey and kill them quickly. Parasites: are usually much smaller than their victims and often harvest nutrients without causing death. Endoparasites: live INSIDE their hosts and usually have simple wormlike bodies (ex: Tapeworms attach to host's intestinal wall and absorb nutrients directly from their surroundings) Ectoparasites: live OUTSIDE their hosts. Usually have limbs or mouthparts that allow them to grasp the host and mouthparts that allow them to pierce their host's skin and suck the nutrient-rich fluids inside.
distinguish between herbivores, carnivores, detritovores, omnivores discuss predators discuss parasites ectoparasites endoparasites
A particular photosynthetic pigment absorbs specific wavelengths of light. Thus, the presence of different pigments means that different species absorb different wavelengths in the electromagnetic spectrum. Because diverse combinations of pigments evolved, eukaryotic species could harvest unique wavelengths of light and avoid competition.
diversification of pigments
A relatively simple pathway of energy flow through a few species, each at a different trophic level, in an ecosystem. Might include, for example, a primary producer, a primary consumer, a secondary consumer, and a decomposer.
food chain
gastrulation: formation of gut and embryonic germ layers. protostomes: gastrulation- pore becomes mouth. formation of coelom- block of solid mesoderm splits to form coelom. Vast majority of animal species, including arthropods, mollusks, and annelids are protostomes. deuterostomes: gastrulation- pore becomes anus. formation of coelom- mesoderm pockets pinch off of gut to form coelom. Humans and other chordates are deuterostomes.
gastrulation - formation of gut and embryonic germ layers - page 606 - figure 32.7-a coelom formation -- page 606 - figure 32.7-b
An evolutionary unit that includes an ancestral population and all of its descendants but no others. Also called a clade or lineage.
monophyletic group