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112 Cards in this Set
- Front
- Back
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of 1.7 million species of organisms, how many are animals?
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1.3 million
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why is a platapus a mammal?
what traits does it have that it doesn't distinguish it as a mammaL? what type of mammal and where found? |
it has mammary glands and hair.
lays eggs, has a bill to locate food with closed eyes underwater MONOTREMES found in New Guinea and Austrailia |
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what phyla is this chapt discussing?
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ANIMALIA?
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What is an animal
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Animals are multicellular, heterotrophic eukaryotes that obtain nutriets by ingestion
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Define ingestion
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eating food. This mode of nutrition contrants animals with fungi, which absorb nutrients after digesting food outside their body. Animals digest food within their body after ingesting other organisms, dead or alive, whole or by the piece.
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What are distinctive features of animal cells?
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Animal cells lack the cell walls that provide strong support in the bodies of plants and fungi. They are held together by extracellular structural proteins and by intercellular juntions. Most animals have muscle cells for movement and nerve cells for conducting impulses.
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Discuss the animal life cycle briefly
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most animals are diploid and reproduce sexually; eggs and sperm are th eonly haploid cells.
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Discuss the animal life cycle by steps
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1`. male and female adult animals make haploid gametes by meiosis.
2. an egg and a sperm fugse, producing a zygote 3. the zygote divides by mitosis, forming 4 an embyonic stage called a BLASTULA, which is a hollow ball of cells 5. in a sea star one side of th eblastula fods inward, forming a stage called GASTRULA. 6. the internal sac formed by gastrulation becomes the digestive tract, lined by a cell layter called the ENDODERM. The embryo also has an ectoderm, an outer cell layer that gives rise to the outer covering of ht eanimal and, in some phyla, to the central nervous system. Most animals have a third embryonic layer, known as the mesoderm, that forms the muscles and most other internal organs. After the gastrula stage, many animals develop diretly into adults. others such as a sea star, developi into one or more larval stages first. 7. a larva is an immature individual that looks different from the adult animal. the larva undergoes a major change of body form, called metamorphosis. 8. in becoming an adult capable of reproducing sexually |
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define blastula
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hollow ball of cells
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define gastrula
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stage when blastula folds inward
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define endoderm
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cell layer that lines the digestive tract
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define ectoderm
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an outer cell layer that gives rise to the outer covering of th eanimal and in some to the cns
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mesoderm
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third embryonic layer that forms the muscles and most internal organs
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define larva
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immature individual that looks different from the adult animal
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define metamorphosis
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major change of body form
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transformation of a zygote into an adult animal
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it's controlled by a specific regulatory genes. all eukaryotes have regulatory genes that contain dna sequences called HOMEOBOXES.
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what family of genes play important roles in the development of animal embryos?
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Hox genes
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wrap up the distinguishing characteristics of animals
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Multicellular, eukaryotic herterotrophs that ingest their food; no cell walls, unique cell junctions, nerve and muscle cells, sexual reproductive and life cycles with unique embryonic stages; unique developmental genes
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the ancestor of animals was probably what?
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CHOANOFLAGELLATES: a colonial, flagellated protist according to molecular clock calculations (billion years ago)
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how colonial flaggellated protists evolved into simple animal with specialized cells arranged in two laters
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1. the earliest colonial aggreates may have only been a few cells
2. some larger colonies may have formed hollow spheres 3. cells in the colony may have become specialized for functions such as reproduction, locomotion, and feeding 4. a smiple multicellular organism with cell layer smight ahve vevoled as cells on one side of hte colony folded inward 5. eventually a gastrula-like "proto-animal" may have evolved |
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oldest known animal fossils date form what time
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Precambrian, 575 million years ago that represented several different soft bodied forms that were too complex to have been the first animals
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define Cambrian explosion
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rapid appearance of most major groups of complex animals around
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What ecological causes ignited the Cambrian explosion?
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ecological causes: the evloution of hard body coverings led to complex predator-prey relationships and diverse adaptations for feeding, motility, and procreation
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What geological causes ignited the Cambrian explosion?
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atmospheric oxygen had reached a high enough concwntration to support the metabolism of active, mobile animals
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What genetic causes ignited the Cambrian explosion?
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the evolution of the Hox complex of regulatory genes. diversity in the body form is associated with variations in the spatial and temporal expression of tese genes within developing embryos
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define invertebrates
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lacking of a vertebal column/ backbone
35 phyla lack vertebrates |
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wrap up the main difference between a colonial organism and an organism that is multicellular
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the cells of a multicellular organism are most specialized and interdependent than are the cells of a colonial organism
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one way biologists categorize the diversity of animals is by body structure, "body plan"
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these distinctions are used to help infer th ephylogentic relationships between animal groups
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one way biologists categorize the diversity of animals is by body structure, "body plan"
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these distinctions are used to help infer th ephylogentic relationships between animal groups
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define radial symmetry
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ex: sea anemone
the body parts radiate form teh center. any imaginary cslice through the central axis divdes a radially symetrical animal into miorror images. the animal has a top and a bottom, but not right and left sides usually sedentary or passively drifting, meeting its nenviornment equally on all sides |
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define bilateral symmetry
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ex: lobster
mirror image right and left sides usually active and travel headfirst through th eenvironment with their eyes and other sense organs contacting th eenviornment first |
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define anterior
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front end
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define posterior
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back end
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define dorsal
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top surface
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define ventral
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bottom surface
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animals with 3 tissue layers may be characterized by the presence or absense of a BODY CAVITY.
define body cavity |
fluid filled space between the digestive tract and body wall cushions the internal organs and enables them to gorw and move independently.
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In soft bodied animals, a noncompressible fluid in the body caity forms a HYDROSTATIC SKELETON
define hydrostatic skeleton |
a rigid structure against which muscles contract, moving th eanimal
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characteristics of a roundworm
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has a body cavity called a PSEUDOCOELOM (false, hollow)
*not completely lined by tissue derized from mesoderm |
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characteristics of a segmented worm
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has a body cavity called a true COELOM
*lined by a tissue derived from mesoderm |
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Animals with three tissue layers can be separted into two groups based on details of their embryonic development, such as fate of opening formed during gastrulation that leads to the digestive tract.
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protostomes and deuterostomes
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protostomes
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first, mouth
mouth |
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deuterostomes
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second, mouth
anus, mouth |
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wrap up the four features of the animal's body plan
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symmetry, # of tissue layers, body cavity type, embryonic dvelopment
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what is the first branch that splits the sponges form the clade of EUMETAZONES "true animals"
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animals with true tissues
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seond branch separates the animals with radial symmetry from bilateral symmetry
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most animal phyla belong to the clade of bilaterians
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morphology based tree dvides th ebilaterians into what two clades based on embryology
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deuterostomes and protostomes
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define sponges
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stationary animals that have a thick walled sac perforated with holes to let water into a central cavity then flow out
some have branching water canals majority of these species are marine, some fresh water lack body symmetry |
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types of sponges
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Scypha resemble simple sacs
azure vase sponge ihave folded body walls and irrgular shapes |
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the body of a sponge consists of two layers of cells separted by a geloatinous region. waht are tehy?
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Choanocyptes: inner later of flagellated cells that sweet water through teh sponge's body. they trap food particles in mucus on the membranous collars that surround th ebase of their flagella and then engult th efood by phagocytosis
AMEOBOCYTES: middle body region that produce skeletal fibers composed of mineral containing patricles or a felxible protein called SPONGIN they pick up food packaged in food vaculoes from choanocytes, digest it, and carry the nutrients to other cells |
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sponges are exampoles of SUSPENSION FEEDERS.
define suspension feeders |
animals that collect food particales form water passed through a type of food trapping equipment
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how do sponges feed?
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they collect food particles form water that streams through their pourous bodies
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define sessile
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adults sponges that are anchored in place; they can't escape predators but the can producedefenseive compounds such as toxin and antibiotics that defer pathogens, parasites, and predators
sopme of these compounds may prove useful to huimans as new drugs they trap particles, performing an ecological service by purifying the water around them |
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why are sponges so simple?
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they have no nerves or muscles, though thier individual cells can sense and react to change sin the environment
cell layers are loose federations of cells but ar enot considered true tissues |
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wrap up why it is thought that sponges represent th earliest branch of th eanimal kindom
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sponges lack symmetry and true tissues, and their choanocytes resemple cenrtain flaggelated protists
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Cnidaria: hydras, jellies, sea anemonoes, and corals.How are they characterized
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by radial symmetry and only two tissue layers. it has a simply body that has an outer epidermis and an inner cell layer that lines the digestive cavity. A jelly-filled middle region may have scattered amoeboid cells. Contractile tissues and nerves occur in.
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Cnidarians exhibit two kinds of radially symmmetrical body forms
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polyp and medusa
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define polyp
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cylindrical body with tentacles projecting from one end. mostly stationary.
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define medusa
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shaped like an umbrella with a fringe of tentacles around the lower edge. they can move freely about in the water.
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How do cnidarians eat?
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They are carnivores that use their tentacles to capture small animals and protists and to push the prey into their mouths.
Polyp: the mouth is on th etop of th ebody at the hub of th eradiating tentacles medusa: mouth is in the center of the undersurface the mouth (only opening) leads into a digestive compartment called a GASTROVASCULAR CAVITY |
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where does undigested food and other wastes exit through?
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the gastrovascular cavity
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waht does th eGgastrovascular cavity do?
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it circulates fluid that services internal cells. it acts as a hydrostatic skeleton, fluid in the cavity provides body support and helps give a cnidarian its shape, much like ater in a balloon.
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dfine cnidocytes
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stinging cells that function in de3fense and capture prey. each one contains a fine thread coiled within a capsule when it is dischared, the thread can sting or entangle prey.
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coral animals are cnidarians that secrete what?
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a hard external skeleton
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wrap up three functions of a cnidarian's gastrovascular cavity?
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1. digestion
2. circulation 3. physical support and movement |
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what does the clade Bilateria consist of?
where do they live? |
free living animals or parasitic species with bilateral symmetry and three embryonic tissue layers
flatworms are the simpliest. marine, freshwater, and damp terrestrial habitats |
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what do flatworms have in common with cnidarians?
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they have gastrovascular cavity with only one opening. the brances distribute food throughout the animal
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what are the three major groups of flatworms
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planarias/free living flatworms, flukes, and tapeworms
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basic characteristics about planarians/free-living flatworms
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a planarian has a head with a pair of light sensitive eyespots and a flap at each side that detects chemicals. dense clusters of nerve cells form a simple brain, and a pair of nerve cords connect with small nerves that branch throughout th ebody.
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discuss the gastrovascular cavity of a planarian and how they find food
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it sucks food in though a mouth at the tip of a a muscular tube that projects from the mid ventral surface of the body.
they use cilia on their ventral surface to crawl in search for food. they have muscles that let them twist and turn |
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where do planarians live
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on the undersurfaces of rocks in freshwater ponds and streams
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flukes are flatworms that live as parasites
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they have suckers that attach to their host and a tough protective covering.
reproductive organs occupy nearly hte entire interior of these worms |
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discuss the complex life cycle of flukes
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it has an intermediate host in which larvae develop. th elarvae then infect the final host in which they live as adults.
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tapeworms are also parasitic. where do they inhabit?
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they live in partially digested food in the intestines of their hosts absorbing nutrients across their body surface
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describe the body of tapeworms
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long, ribbonlike body with repeated units
NO digestive tract |
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what does the scolex of tapeworms do?
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the anteriaor end, called the scolex, is armed with hooks and suckers that grasp the host. behind it is hte reproductive structures full of ripe eggs that break off and pass out of the host's body in feces
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like parasitic flukes, tapeworms have a complex life cycle
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involving more than one host
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flatworms and cnidarians differ in symmetry, with flatworms being ______________ and cnidarians being _________, but the animals of both phyla have a __________.
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bilateral
radial gastrovascular cavity |
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nematodes (roundworms) make up the phylum Nematooday. As bilaterians they have what kind of body plan?
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bilateral symmetry and a three tissue layer construction. they have a fluid-filled body cavity (a pseudocoelom) which distributes nutrients and functions as a hydroskeletonand a digestive tract with two openings
UNLIKE FLATWORMS they are cylindrical with a blunt head and tapered tail. body is covered by a cuticle that sheds as it grows secreting a new, larger one |
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define cuticle
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tough, nonliving covering that resits drying and crushing
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define complete digestive tract
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tube form the mouth to the anus. food travels only one way through the system and is processed as it moves along
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where can you find nematodes
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they live irtually everywher ethere is rotting organic matter. they are important deocmposers in soil and on the bottom of lakes and oceans. others thrive as parasites in moist tissues of plants in th ethe body fluids and tissues of animals
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many species of nematodes are agricultural pests, how?
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they attack th eroots of plants or parasitize animals
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MOLLUSCS are soft bodied ahnimals that are protected by a hard shell. Examples of animals?
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snials, slugs, oysters, clams, octopuses, and squids
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what ar ehte three main parts of a mollusc
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musular foot,
a visceral mass a mantle |
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define foot
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functions in locomtion
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define visceral mass
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contains most of the internal organs including the reproductive organs
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define mantle
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a fold of tissue that drapes over the visceral mass and secretes a shell in molluscs such as clams and snails which extends beyond th evisceral mass, producing a waterfilled chamber called th ematle cavity which houses the gills
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define radula
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a unique rasping organ in molluscs, it is used to scrape up food.
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life cycle of marine molluscs includes
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a ciliated larva called a trochophore
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molluscs have a true coelom and circulatory systme
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in contrast with flatworms whcih have no body cavity and nematodes which have pseudocoelom
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define circulatory system
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an organ system that pumps blood and distributes nutrients and oxygen throughout the body
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what are the three diverse gropus of molluscs
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gastropods (snails and slugs), bivalves (clams, scallops, and oysters), and cephalopods (quids and octopuses)
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where are gastropods found?
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fresh water, salt water, and land (only molluscs that do)
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how do gastropods protect themselves
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they have a spiraled shell where they can retreat when threatened
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describe bivalves
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-hard shells diveded into two halves that are hinged
-suspension feeders -mantel cavity has gills that are used for feeding and gas exhange -gills trap food paticles in water -cilia sweep particles to the mouth -sedentary, living in sand or mud -use foot for digging and anchoring |
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cephalopods are adapted to the lifestle of fast, agile predators. what do they use?
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use beaklike jaws and a radula to crush or rip prey apart. the mouth is at the base of the foot
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describe the organs of cephalopods
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-large brains
-sophisticated sense organs -each eye cotains a lens that focuses light and a retina on which clear image form |
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define segmentaion
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the subdivision of the body along its length into a series of repeated parts which allows for greater flexibilithy and mobility
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define annelid
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segmented worms that uses its flexible, semented body to crawl and burror rapidly into the soil
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where are annelids found?
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in damp soil, in teh sea, and in freshwater habitats
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how do annelids find food?
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some swim in pursuit of food, most are bottom dwelling scavengers that burrow in sand and mud
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what are th ethree groups of annelids?
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-earthworms
-polychaetes -leeches |
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describe the body structures of earthworms
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-internal body structrures are repeated within each segment
-nervous system includs a brain and a ventral nerve cord w/ cells -excretory organs dispose of fluid wastes -digestive tract passes through the segment walls form teh mouth to the anus |
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define open circulatory system
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blood is pumped through vessels that open into body cavities where organs are bathed directly in blood
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define closed circulatory system
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blood remains enclosed in vessels as it distributes nutrients and oxygen thgouhout the body
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eathrworms are hermaphrodites
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they ahve both male and female reproductive structures but they mate and cross fertilze by exchanging sperm
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describe the eating habits of earthworms
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they eat theiir way through the soil, extracting nutrietns as soil passes through their digestive tube. undigetsted material, mixed w/ muscus, is elimiated as castings/feces through the anus
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describe polychaetes
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they are marine that live in tubes and extend feathery appendages coated w/ mucus that trap suspended food particles.
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describe the body shape of polychaetes
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each segment has a pair of fleshy, paddle like appendages with stiff pristles thath help the worm wriggle in search of small invertebrates to eat. the appendages are supplied w/ blood vessels and function in gas exchange
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define leeches
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group of annelids that are notorious for their bloodsucking habits
most are fcarnivores that eat invertebrats like snails and insects |
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where do leeches live
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fresh water, marine, some land
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how do leeches feed?
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some use razor like jaws to slit the skin of an animal. the host is oblivious to this attack bc it secretes an anesthetic and anticoagulant into teh wound then it sucks as much blood as it can hold, ten times own weight. leech can last for months w/o another meal
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