Exam 3 Flashcards
What are the defining characters of animals?
Monophyletic (All animals share a common
ancestor), Multicellular(Specialization), Extra cellular matrix and collagen(an extensive extracellular matrix used for communication and collagen holding cells
together), sexual reproduction(fusion of haploid gametes), blastula stage of development(zygote reproduces through mitosis forming a hollow sphere), distinct germ layers (endoderm, mesoderm, ectoderm), Homeotic (master regulatory genes) and hox(determine body plan) genes, symmetry (bilateral or radial), muscles, nervous system, senses, heterotrophs,
Would you consider a sponge to be an animal, explain. Be sure to include a description of the characters of both sponges and animals in your explanation.
Yes, they have
* Differentiated cell types
* Apoptosis (Programmed cell death)
* Recognition of self from non-self for
innate immunity
* Developmental signaling and gene
regulation
* Regulation of cell cycle and growth.
* They make Collagen.
They do lack other animal traits like:
Germ layers
* Symmetry
* Muscles and a nervous system
* Most Hox Genes (Hox genes arose after
they split from most animals
Explain why cephalization occurs in animals with bilateral symmetry, but not radial symmetry.
Cephalization occurs in all bilaterally symmetrical animals because there is an advantage in having the end that goes first, as the animal moves, fitted out with sense organs—on the premise that it is better to know where you are going than where you have been.
Explain why cnidarians do not require a circulatory system.
Cnidarians lack organs. This means that they do not have respiratory or circulatory systems. Like the cells in sponges, the cells in cnidarians get oxygen directly from the water surrounding them. Little volume but a lot of surface area.
List the defining characters of
Cnidarians
Arthropods
Mollusks
Chordates
Cnidarians: Radial Symmetry (sort of)
Two Germ Layers
Arthropods: Hard exoskeleton made of chitin
Jointed limbs
Compound eyes
Mollusks: Mantle used for excretion and breathing
Radula (except bivalves)
Chrodates: animals with backbones (vertebrates)
Muscular post-anal tail
Pharyngeal slits, gills in fish
Dorsal nerve cord
notochord
What’s the average body temperature of humans?
97.7-99.6 and closer to 98.2°F
Define homeostasis.
an organism’s ability to resist
change and maintain its set points, or the relatively
constant internal environment.
Explain why there are no perfectly adapted animals (include a trade-offs and provide examples)
Role of fitness in trade-offs
Compromises between traits
No perfectly adapted species
Type 1 vs Type II muscles: Endurance vs Strength
Speed vs camouflage
What’s the difference between acclimation and adaptation, explain why you cannot adapt to your environment. (provide examples)
Adaptation(skin color) is a long-term permanent adjustment of a group of organisms to a changing environment. Acclimatization(tan) is a short-term rapid temporary adjustment of an organism to a changing environment. Adaptation takes place over generations
Name the four types of tissues in the human body.
Nervous tissue, muscle tissue, epithelial tissue, connective tissue.
Which types of tissues have excitable membranes?
Muscle and nervous
Animals living in cold water face several challenges:
How could they maintain membrane fluidity in cold temperatures? Explain.
Cold water animals have short poly-unsaturated fatty acids in their membranes. The bent chain prevents the membrane from solidifying.
Animals living in cold water face several challenges:
What would happen if their membranes became too viscous or rigid?
If cellular membranes become too rigid then carbon dioxide and oxygen cannot easily pass the membrane, in contrast if cellular membranes become too fluid, then they won’t be able to regulate the movement of materials across them.
Importance of thermoregulation
How is special fluid connective tissue different from the other types of connective tissue?
They do not contain fiber
Mobile cells
Blood transports materials throughout the body
In class I described bilateral animals as a “tube”, What did I mean by that (Hint: The digestive tract)
Mouth and anus. Front/back, left/right, top/bottom
Metabolism
The sum of all chemical reactions in an organism
Metabolic rate
Overall rate of energy consumption by an individual.
Base metabolic rate
The rate at which an animal consumes oxygen while at rest
Explain why an elephant has a higher whole-animal metabolic rate than a shrew, but a shrew has a much higher mass-specific metabolic rate.
An elephant has more mass and eats more to maintain its metabolic processes, but a shrew is much smaller and loses energy faster so it must consume more per gram. As body volume increases, surface area increases more slowly. So an elephant radiates and loses less energy per gram than a mouse and thus requires less replacement energy per gram.
Are animals open or closed systems?
open
