Animal

qas: question: Where does the word animal come from?
answers: text: Latin animalis

question: What does the Latin word animalis mean?
answers: text: having breath, having soul or living being

question: The word animal is usually only used to refer to what?
answers: text: non-human members of the kingdom Animalia

question: The biological definition of the word animal refers to all member of what kingdom?
answers: text: Animalia

question: What are some of the creatures included in the kingdom of Animalia?
answers: text: sponges, jellyfish, insects, and humans
context: The word "animal" comes from the Latin animalis, meaning having breath, having soul or living being. In everyday non-scientific usage the word excludes humans – that is, "animal" is often used to refer only to non-human members of the kingdom Animalia; often, only closer relatives of humans such as mammals, or mammals and other vertebrates, are meant. The biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans.

qas: question: What type of cells do all animals have?
answers: text: eukaryotic

question: What is the extracellular matrix surrounding eukaryotic cells made of?
answers: text: collagen and elastic glycoproteins

question: What is formed when the collagen and elastic glycoproteins surrounding eukaryotic cells are calcified? 
answers: text: shells, bones, and spicules

question: How are cells held in place in plants and fungi?
answers: text: cell walls

question: What are the intercellular junctions unique to animal cells?
answers: text: tight junctions, gap junctions, and desmosomes
context: All animals have eukaryotic cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. This may be calcified to form structures like shells, bones, and spicules. During development, it forms a relatively flexible framework upon which cells can move about and be reorganized, making complex structures possible. In contrast, other multicellular organisms, like plants and fungi, have cells held in place by cell walls, and so develop by progressive growth. Also, unique to animal cells are the following intercellular junctions: tight junctions, gap junctions, and desmosomes.

qas: question: What is the biological interaction where a predator feeds on its prey called?
answers: text: Predation

question: The act of predation typically results in what for the prey?
answers: text: death

question: What is the consumption of dead organic matter called?
answers: text: detritivory

question: Why do parasitic species lay their eggs on their prey?
answers: text: their offspring to feed on its decaying corpse

question: The evolutionary arms race between prey and predator has resulted in what?
answers: text: various antipredator adaptations
context: Predation is a biological interaction where a predator (a heterotroph that is hunting) feeds on its prey (the organism that is attacked). Predators may or may not kill their prey prior to feeding on them, but the act of predation almost always results in the death of the prey. The other main category of consumption is detritivory, the consumption of dead organic matter. It can at times be difficult to separate the two feeding behaviours, for example, where parasitic species prey on a host organism and then lay their eggs on it for their offspring to feed on its decaying corpse. Selective pressures imposed on one another has led to an evolutionary arms race between prey and predator, resulting in various antipredator adaptations.

qas: question: Ctenophora and the Cnidaria include what sea creatures?
answers: text: anemones, corals, and jellyfish

question: The digestive chambers of the Ctenophora and the Cnidaria serve as what?
answers: text: both the mouth and the anus

question: What are the 2 main germ systems in the Ctenophora and the Cnidaria called?
answers: text: ectoderm and endoderm

question: What are the Ctenophora and the Cnidaria animals sometimes called?
answers: text: diploblastic

question: What differentiates placozoans from the ctenophora and the cnidaria?
answers: text: they do not have a permanent digestive chamber
context: Among the other phyla, the Ctenophora and the Cnidaria, which includes sea anemones, corals, and jellyfish, are radially symmetric and have digestive chambers with a single opening, which serves as both the mouth and the anus. Both have distinct tissues, but they are not organized into organs. There are only two main germ layers, the ectoderm and endoderm, with only scattered cells between them. As such, these animals are sometimes called diploblastic. The tiny placozoans are similar, but they do not have a permanent digestive chamber.

qas: question: What sets animals apart from bacteria  and most protists?
answers: text: Animals are eukaryotic and multicellular

question: What are organisms called that digest food in an internal chamber?
answers: text: heterotrophic

question: What is another way in which animals are distinguished from plants and algae?
answers: text: lacking rigid cell walls

question: The blastula stage is a characteristic exclusive to what organism?
answers: text: animals
context: Animals have several characteristics that set them apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and most protists. They are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking rigid cell walls. All animals are motile, if only at certain life stages. In most animals, embryos pass through a blastula stage, which is a characteristic exclusive to animals.

qas: question: What is the hollow sphere that a zygote initially develops into called?
answers: text: blastula

question: In sponges, how do blastula develop into a new sponge?
answers: text: swim to a new location

question: What are the 2 germ layers formed by most blastula?
answers: text: an external ectoderm and an internal endoderm

question: What may be formed between the external ectoderm and an internal endoderm layers?
answers: text: mesoderm

question: What do the external ectoderm and an internal endoderm layers develop into?
answers: text: tissues and organs
context: A zygote initially develops into a hollow sphere, called a blastula, which undergoes rearrangement and differentiation. In sponges, blastula larvae swim to a new location and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber, and two separate germ layers — an external ectoderm and an internal endoderm. In most cases, a mesoderm also develops between them. These germ layers then differentiate to form tissues and organs.

qas: question: How long ago do some paleontologists believe that animals first appeared?
answers: text: 1 billion years

question: Fossils found in the Tonian period indicate the presence of what creatures?
answers: text: triploblastic worms

question: Triploblastic worms were comparable in size to what other creatures?
answers: text: earthworms

question: When was the beginning of the Tonian period?
answers: text: around 1 billion years ago

question: What produces tracks similar to the fossilized tracks discovered by paleontologists?
answers: text: Gromia sphaerica
context: Some paleontologists suggest that animals appeared much earlier than the Cambrian explosion, possibly as early as 1 billion years ago. Trace fossils such as tracks and burrows found in the Tonian period indicate the presence of triploblastic worms, like metazoans, roughly as large (about 5 mm wide) and complex as earthworms. During the beginning of the Tonian period around 1 billion years ago, there was a decrease in Stromatolite diversity, which may indicate the appearance of grazing animals, since stromatolite diversity increased when grazing animals went extinct at the End Permian and End Ordovician extinction events, and decreased shortly after the grazer populations recovered. However the discovery that tracks very similar to these early trace fossils are produced today by the giant single-celled protist Gromia sphaerica casts doubt on their interpretation as evidence of early animal evolution.

qas: question: It is believed that animals evolved from what?
answers: text: a flagellated eukaryote

question: What are the closest known living relatives of animals?
answers: text: choanoflagellates

question: What is the name of the supergroup that animals have been placed in by molecular studies?
answers: text: opisthokonts

question: The opisthokonts also include what other organisms?
answers: text: choanoflagellates, fungi and a few small parasitic protists

question: Where does the name opisthokonts come from?
answers: text: the posterior location of the flagellum in motile cells
context: Animals are generally considered to have evolved from a flagellated eukaryote. Their closest known living relatives are the choanoflagellates, collared flagellates that have a morphology similar to the choanocytes of certain sponges. Molecular studies place animals in a supergroup called the opisthokonts, which also include the choanoflagellates, fungi and a few small parasitic protists. The name comes from the posterior location of the flagellum in motile cells, such as most animal spermatozoa, whereas other eukaryotes tend to have anterior flagella.

qas: question: What is the group of animals that often have a specialized head with feeding and sensory organs called?
answers: text: Bilateria

question: How many openings in the digestive chamber do animals in the Bilateria group have?
answers: text: two

question: What are the openings in the digestive chambers for animals in the Bilateria group called?
answers: text: mouth and an anus

question: What is the internal body cavity of animals in the Bilateria group called?
answers: text: coelom or pseudocoelom
context: The remaining animals form a monophyletic group called the Bilateria. For the most part, they are bilaterally symmetric, and often have a specialized head with feeding and sensory organs. The body is triploblastic, i.e. all three germ layers are well-developed, and tissues form distinct organs. The digestive chamber has two openings, a mouth and an anus, and there is also an internal body cavity called a coelom or pseudocoelom. There are exceptions to each of these characteristics, however — for instance adult echinoderms are radially symmetric, and certain parasitic worms have extremely simplified body structures.

qas: question: What are some examples of non-bilaterian animals?
answers: text: Porifera, Ctenophora, Cnidaria and Placozoa

question: What are animals whose body plans display bilateral symmetry called?
answers: text: bilaterian

question: Animals in what group are thought to form a monophyletic group?
answers: text: bilaterian
context: Traditional morphological and modern molecular phylogenetic analysis have both recognized a major evolutionary transition from "non-bilaterian" animals, which are those lacking a bilaterally symmetric body plan (Porifera, Ctenophora, Cnidaria and Placozoa), to "bilaterian" animals (Bilateria) whose body plans display bilateral symmetry. The latter are further classified based on a major division between Deuterostomes and Protostomes. The relationships among non-bilaterian animals are disputed, but all bilaterian animals are thought to form a monophyletic group. Current understanding of the relationships among the major groups of animals is summarized by the following cladogram:

qas: question: What groups is named after the trait of growth by moulting or ecdysis?
answers: text: Ecdysozoa

question: What are some animals in the Arthropoda group?
answers: text: insects, spiders, crabs

question: Organisms in the Arthropoda group have bodies that are divided into what?
answers: text: repeating segments

question: What groups are relatives of the arthropods?
answers: text: Onychophora and Tardigrada

question: What is another name for roundworms?
answers: text: Nematoda
context: The Ecdysozoa are protostomes, named after the common trait of growth by moulting or ecdysis. The largest animal phylum belongs here, the Arthropoda, including insects, spiders, crabs, and their kin. All these organisms have a body divided into repeating segments, typically with paired appendages. Two smaller phyla, the Onychophora and Tardigrada, are close relatives of the arthropods and share these traits. The ecdysozoans also include the Nematoda or roundworms, perhaps the second largest animal phylum. Roundworms are typically microscopic, and occur in nearly every environment where there is water. A number are important parasites. Smaller phyla related to them are the Nematomorpha or horsehair worms, and the Kinorhyncha, Priapulida, and Loricifera. These groups have a reduced coelom, called a pseudocoelom.

qas: question: Why is it more economical for scientists to study a small number of species?
answers: text: the great diversity found in animals

question: Which organisms were among the first life-forms to be genetically sequenced?
answers: text: fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans

question: Why are  the fruit fly and the nematode the most intensively studied metazoan model organisms?
answers: text: they are easy to keep and breed

question: Analysis of what genome has emphasised the importance of sponges, placozoans, and choanoflagellates  in explaining the arrival of 1500 ancestral genes unique to the Eumetazoa?
answers: text: starlet sea anemone
context: Because of the great diversity found in animals, it is more economical for scientists to study a small number of chosen species so that connections can be drawn from their work and conclusions extrapolated about how animals function in general. Because they are easy to keep and breed, the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans have long been the most intensively studied metazoan model organisms, and were among the first life-forms to be genetically sequenced. This was facilitated by the severely reduced state of their genomes, but as many genes, introns, and linkages lost, these ecdysozoans can teach us little about the origins of animals in general. The extent of this type of evolution within the superphylum will be revealed by the crustacean, annelid, and molluscan genome projects currently in progress. Analysis of the starlet sea anemone genome has emphasised the importance of sponges, placozoans, and choanoflagellates, also being sequenced, in explaining the arrival of 1500 ancestral genes unique to the Eumetazoa.

qas: question: What are two of the most successful animal phyla?
answers: text: Mollusca and Annelida

question: What are some of the animals in Mollusca?
answers: text: snails, clams, and squids

question: What are some of the animals in Annelida?
answers: text: earthworms and leeches

question: Why are the Mollusca and Annelida considered to be close relatives?
answers: text: common presence of trochophore larvae

question: What are the phyla that have a ring of ciliated tentacles around the mouth called?
answers: text: lophophore
context: The Lophotrochozoa, evolved within Protostomia, include two of the most successful animal phyla, the Mollusca and Annelida. The former, which is the second-largest animal phylum by number of described species, includes animals such as snails, clams, and squids, and the latter comprises the segmented worms, such as earthworms and leeches. These two groups have long been considered close relatives because of the common presence of trochophore larvae, but the annelids were considered closer to the arthropods because they are both segmented. Now, this is generally considered convergent evolution, owing to many morphological and genetic differences between the two phyla. The Lophotrochozoa also include the Nemertea or ribbon worms, the Sipuncula, and several phyla that have a ring of ciliated tentacles around the mouth, called a lophophore. These were traditionally grouped together as the lophophorates. but it now appears that the lophophorate group may be paraphyletic, with some closer to the nemerteans and some to the molluscs and annelids. They include the Brachiopoda or lamp shells, which are prominent in the fossil record, the Entoprocta, the Phoronida, and possibly the Bryozoa or moss animals.

qas: question: Animal phyla that are recognized for their lack of bilateral symmetry are thought to have come from where?
answers: text: other animals early in evolution

question: Which animal represents the oldest animal phyla?
answers: text: sponges

question: How do sponges typically feed?
answers: text: drawing in water through pores

question: During what time were a series of phylogenomic studies conducted that found support for comb jellies as the basal lineage of animals?
answers: text: 2008-2015
context: Several animal phyla are recognized for their lack of bilateral symmetry, and are thought to have diverged from other animals early in evolution. Among these, the sponges (Porifera) were long thought to have diverged first, representing the oldest animal phylum. They lack the complex organization found in most other phyla. Their cells are differentiated, but in most cases not organized into distinct tissues. Sponges typically feed by drawing in water through pores. However, a series of phylogenomic studies from 2008-2015 have found support for Ctenophora, or comb jellies, as the basal lineage of animals. This result has been controversial, since it would imply that that sponges may not be so primitive, but may instead be secondarily simplified. Other researchers have argued that the placement of Ctenophora as the earliest-diverging animal phylum is a statistical anomaly caused by the high rate of evolution in ctenophore genomes.

qas: question: What do deuterostomes and protostomes have in common?
answers: text: both groups possess a complete digestive tract

question: In which group does the anus form first, with the mouth developing secondarily?
answers: text: deuterostomes

question: What is the process in which cells fill in the interior of the gastrula to form the mesoderm called?
answers: text: schizocoelous development

question: What is the process in which the mesoderm is formed through invagination of the endoderm called?
answers: text: enterocoelic pouching

question: What do deuterostome embryos undergo during cell division?
answers: text: radial cleavage
context: Deuterostomes differ from protostomes in several ways. Animals from both groups possess a complete digestive tract. However, in protostomes, the first opening of the gut to appear in embryological development (the archenteron) develops into the mouth, with the anus forming secondarily. In deuterostomes the anus forms first, with the mouth developing secondarily. In most protostomes, cells simply fill in the interior of the gastrula to form the mesoderm, called schizocoelous development, but in deuterostomes, it forms through invagination of the endoderm, called enterocoelic pouching. Deuterostome embryos undergo radial cleavage during cell division, while protostomes undergo spiral cleavage.

qas: question: What is another name for flatworm?
answers: text: Platyhelminthes

question: What are some parasites included in the Platyhelminthes group?
answers: text: flukes and tapeworms

question: What does acoelomates mean?
answers: text: lacking a body cavity

question: What are the flatworms closest relative?
answers: text: Gastrotricha

question: Where are the rotifera most prominent?
answers: text: in aqueous environments
context: The Platyzoa include the phylum Platyhelminthes, the flatworms. These were originally considered some of the most primitive Bilateria, but it now appears they developed from more complex ancestors. A number of parasites are included in this group, such as the flukes and tapeworms. Flatworms are acoelomates, lacking a body cavity, as are their closest relatives, the microscopic Gastrotricha. The other platyzoan phyla are mostly microscopic and pseudocoelomate. The most prominent are the Rotifera or rotifers, which are common in aqueous environments. They also include the Acanthocephala or spiny-headed worms, the Gnathostomulida, Micrognathozoa, and possibly the Cycliophora. These groups share the presence of complex jaws, from which they are called the Gnathifera.

qas: question: How do most animals use the energy of sunlight?
answers: text: eating plants or plant-eating animals

question: What do plants use to convert inorganic molecules into carbohydrates, fats, proteins and other biomolecules?
answers: text: light

question: What does photosynthesis convert the energy of sunlight into?
answers: text: chemical energy

question: When an animal eats plants or another animal that has eaten plants, what happens to the reduced carbon compounds in the food?
answers: text: become a source of energy and building materials for the animal

question: What happens with the reduced carbon compounds in the food are broken down releasing stored solar energy?
answers: text: giving the animal the energy required for motion
context: Most animals indirectly use the energy of sunlight by eating plants or plant-eating animals. Most plants use light to convert inorganic molecules in their environment into carbohydrates, fats, proteins and other biomolecules, characteristically containing reduced carbon in the form of carbon-hydrogen bonds. Starting with carbon dioxide (CO2) and water (H2O), photosynthesis converts the energy of sunlight into chemical energy in the form of simple sugars (e.g., glucose), with the release of molecular oxygen. These sugars are then used as the building blocks for plant growth, including the production of other biomolecules. When an animal eats plants (or eats other animals which have eaten plants), the reduced carbon compounds in the food become a source of energy and building materials for the animal. They are either used directly to help the animal grow, or broken down, releasing stored solar energy, and giving the animal the energy required for motion.