Animal Evolution and Biology (Exam #2)

What characterizes an animal (5 things)?

They are multicellular, heterotrophic, eukaryotes that have tissues which develop from embryonic laters, diploid dominant, & reproduce sexually.

What kind of genes regulates similar development in animals?

Hox genes

What happens to a zygote in the first step of development?

It goes through cleavage to form an 8 celled embryo

What does the embryo divide to form?

A Blastula (hollow ball surrounding a blastocoel)

What happens to the blastula in the development of an animal?

Undergoes gastrulation where one side folds inside forming a pouch with an endoderm and actoderm with an opening to the outside called a blastopore

When was the origin of animals?

About 770 million years ago in the neoprotezoic era

What was the Cambrian Explosion?

550 mil years ago, gave rise to the great diversity of animals we have today due to increase in atmospheric O2, and the evolution of predator/prey relationships

What is bilateral symmetry?

When an animal has one plane that can cut them symmetrically

What is radial symmetry?

When an animal can be cut symmetrically on more than one plane

What is diploblastic?

Animals with 2 germ layers in the immature cell

What is triploblastic?

Animals with 3 germ layers in the immature cell

What are coelom and hemocoels?

Body cavities that open during the forming of the embryo

What is a protostome?

An animal that develops “mouth first”, cleavage is spiral, mouth develops from blastopore

What is a deutrostrome?

An animal that develops anus first, cleavage is radial & indeterminate, & anus develops from the blastopore

What are phylum Porifera and what are their characteristics?

Sponges, no symmetry, no body cavity

What are phylum Cnidaria and what are its characteristics?

Jellyfish, sea anemones, radial symmetry, diploblastic tissues, no body cavity

What are phylum Platyhelminths and what are their characteristics?

Tapeworms & flukes, bilateral symmetry, tripoloblastic tissues, protostome development, no body cavity

What are phylum Mollusca and what are their characteristics?

Snails & cephalopods, bilateral symmetry, tripoblastic tissues, protostome development, no body cavity

What are phylum Annelida and what are their characteristics?

Segmented worms, bilateral symmetry, tripoblastic tissues, protostome development, body cavity

What are phylum echnodermata and what are their characteristics?

Starfish & sea urchins, radia symmetry, triploblastic tissues, protostome development, body cavity

What is phylum Chordata and what are their characteristics?

Vertebrates, bilateral symmetry, triploblastic tissues, duetrostome development, body cavities

What is phylum nemotoda and what are their characteristics?

Roundworms, bilateral symmetry, triploblastic tissues, protostome development, body cavities

What are phylum Arthropoda and what are their characteristics?

Insects & crustaceans & arachnids, bilateral symmetry, tripoblastic tissues, protostome development, body cavities

What are the 5 families that humans belong to (in order from broadest to most specific)?

Deutrostomes (anus first), chordates (notocord & dorsal hollow nerve), mammalian (hair & milk), eutheria (placenta), and primates

What importnat things distinguish humans from apes?

Bipedal, larger brains, reduced jaw bones, shorter digestive tract

What are the characteristics of Australopiths?

Bipedal adaptations, small brains, longer lower jaw

What are the characteristics of homo habilis?

“Handy man”, bipedal, larger brains, tool use

What are the characteristics of homo erectus?

Bigger brain, better tools, long distance walking, less sexual dimorphism

What are characteristics of homo Neanderthals?

Bigger brains than modern humans, complex tools, inbred w homo Sapiens

What are Homo sapiens?

“Thinking man”, modern humans

How is the evolution of organisms constrained by physics?

The bigger something is, the more muscle is needed. In addition in order to exchange nutrients with an environment an idea surface area to volume ratio is needed

What are the 4 steps to food processing?

Ingestion, digestion, absorption, and elimination

What must a diet supply?

Chemical energy, organic building blocks, and essential nutrients

What’s is filter feeding?

Obtaining small particles/organisms by straining them through water or air

What is substrate feeding?

Strategy where an animal lives on/in their food and eats its way through it

What is bulk feeding?

Eating extremely large portions of food

What is fluid feeding?

Organisms acquire nutrients through liquid sources (sap, blood, nectar)

What is ingestion?

Process by which animals take in their food

What is digestion?

Food is broken down into molecules small enough for absorption through mechanical and chemical processes

What is enzymatic digestion?

Process in which different enzymes break down molecules to produce energy (proteases:protein, amylase, lactase, sucrose;carbs, nuclease;nucleic acid, and lipase;lipids)

What is intracellular digestion?

Molecules broken down inside cells, stored in food vacuoles, tranported in/out through endo/exocytosis

What is extracellular digestion?

Breakdown of food in compartments that are continuous with the outside of an animal

What is a gastrovascular cavity?

Single opening in an animal that digests and distributes nutrients

What is an alimentary canal?

A “complete” digestive tract with series of specialized compartments

What happens in an oral cavity?

Mouth. Mechanical breakdown through chewing and chemical breakdown through saliva

What’s is an esophagus?

Muscular tube that transports food down to the stomach through peristalsis

What does the stomach do?

Processes food into liquid suspension through mechanical (churning) and chemical (stomach acid) breakdown. Gastric juice mixes with food to produce chyme

What does the small intestine do?

Provides the most enzymatic hydrolysis of macromolecules and absorbs nutrients through villi

What does the large intestine do?

Made of the colon, cecum, and rectum, provides final water recovery and forms feces

What is mutualism?

Interaction between 2 species that benefits both

What is a microbiome?

Collection of microorganisms living in and on the body

What is the biological species concept?

Species are defined by their potential to interbreed not their physical similarity

What is the morphological species concept?

distinguishes species by the body shape and structures

What is the ecological species concept?

defines species by their ecological niche

What occurs from reproductive isolation?

causes a species to split, be unable to produce offspring with one another, forming a new species

What are prezygotic barriers?

barriers to reproduction that occur “before the zygote” blocking fertilization (habitat, temporal, behavioral, mechanical, and gametic isolation)

What are postzygotic barriers?

barriers to reproduction that occur “after the zygote” contributing to reproductive isolation (hybrid inviability, hybrid infertility, hybrid breakdown)

What is a hybrid?

An animal formed from two different species

What is a hybrid zone?

a region in which members of different species meet and mate producing at least some offspring of mixed ancestry producing a gradient of alleles

What is allopatric speciation?

population forms a new species because of geographic isolation

What is sympatric speciation?

population forms a new species without geographic isolation

What kind of cleavage do protostomes undergo?

spiral and determinate cleavage

What kind of cleavage do duetrostomes undergo?

Radial and indeterminate cleavage

What are the 3 layers of tissues that develop in animals?

endoderm (inner). mesoderm (middle), ectoderm (outer)

What is a gastrula?

an embryo at the stage following the blastula when it is a hollow cup shaped structure with 3 layers of cells

What is included in the metazoa family?

All animals

What is included in the eumetazoa family?

animals with bilateral or radial symmetry

What are acoela?

small, simple, invertebrate, soft bodied worms

What is included in deuterostomia?

animals with bilateral or radial symmetry who develop anus first

What is included in lophotrochazoa?

animals with bilateral symmetry who develop mouth first

What is included in ecdysozoa?

animals who develop mouth first

What are choanoflagellates?

small suspension feeders that are believed to resemble the common ancestor of animals

What are acoels?

small branch of flatworms

What are monotremes?

classification of mammals that lay eggs 

What are marsupials?

Mammals that give birth to premature offspring that continue to develop outside the body (often in a pouch)

What are great apes?

Primates characterized by larger size, advanced tool use, and longer parental care 

What are hominins?

family of animals including all extinct and present form of humans 

What are eutherian mammals?

animals that have a placenta and develop fully before giving birth 

What are the key characteristics of chordates?

contain a notochord, dorsal hollow nerve cord, pharyngeal slits, and a muscular post anal tail

What are essential nutrients?

substances that the body cannot produce itself and must be obtained from the diet to maintain health

What is hydrolysis?

process in which water is used to help break down larger molecules 

What is protease?

enzyme that breaks down proteins and peptides

What is the function of microvilli in vertebrate digestive systems?

lots of protrusions dramatically increase surface area of the intestine allowing for greater nutrient absorption

What is the function of the hepatic portal vein?

transport nutrient rich blood from digestive organs to the liver allowing it to filter out toxins before it is sent to the rest of the body 

What does the liver do?

removes toxins and drugs from the blood & stores sugar and vitamins 

What is the role of the appendix?

accessory organ, greatly unknown, cultures bacteria for the gut microbiome 

What is the function of the cecum?

further digestes food, particularly water rich food, much bigger in herbivores 

What is the function of the colon?

final water absorption of the digestive system, compacts waste

What is the function of the rectum?

stores waste until it is ready to be excreted

What is the pharynx?

cavity behind the nose and mouth connecting the oral cavity to the esophagus

What is respiration?

process of gas exchange, supplying O2 and disposing of CO2

What is diffusion?

Process by which gas and other materials diffuse through membranes for transport 

What is ventilation?

breathing in and out

What is the circulatory system?

heart and lungs, supplying and transport of oxygen throughout the body 

What is an artery?

a tube that carries blood Away from the heart with thick walls and high pressure

What is a arterioles?

small branch of an artery

What are capillaries?

series of tiny tubes that intersect alowing the transfer of substances through their walls via diffusion between blood and interstatial fluid. trade off between oxygen rich and oxygen poor blood, from arteries to veins 

What are veins?

tubes that carry oxygen poor blood back to the heart with valves that prevent backflow, thinner walls and weaker pressure 

What are venules?

small branches of veins

What are the characteristics of an open circulatory system?

the hemolymph (blood) is also the interstatial fluid, flows with openings, both the heart and body movement help with circulation, lower hydrostatic pressure, better energy conservation