Midterm 1 Flashcards
What are the 6 basic characteristics of animals?
1) Multicellular
2) Heterotrophic
3) Eukaryotic
4) Motile
5) No cell wall
6) Go through blastula
How can animals characterized?
By body plans
How many identified living species of animals are there?
1.3 Million
What are heterotrophs?
Obtain organic molecules from their food that they ingest and digest within their bodies
What are 2 defining characteristics of animals?
1) Nervous tissue
2) Muscle tissues
Definition of tissues
Groups of cells that act as a functional unit
What do parazoans lack?
They have no true tissue
What is the group called for all animals?
Metazoa
What does the group eumetazoa mean?
Animals w/ specialized tissues
How do zoologists sometimes categorize animals by?
Body plan: a set of morphological and developmental traits
How long has the molecular control of gastrulation remained unchanged?
More than 500 million years
What are the 4 characteristics of bilaterally symmetrical animals?
1) Dorsal and ventral (top and bottom)
2) right and left
3) Anterior and posterior (front and back)
4) cephalization: brain
True or False: Bilateral animals are triploblasts and Radial animals are diploblasts?
TRUE
What are the 5 stages of early embryonic development in animals?
1) zygote
2) 8-cell stage
3) Blastula
4) Gastrulation
5) Gastrula
What stage usually dominates the life cycle (diploid or haploid)?
Diploid stage
What are the 3 layers in tissue from outermost to innermost (triploblastic)?
1) Ectoderm
2) Mesoderm
3) Endoderm
What layer of tissue do diploblasts lack?
Mesoderm
Which animal is considered to be the simplest?
Trichoplax adhaerens (TP); used to be th only living species in the phylum placozoa (now there are 4)
What is a pseudocoelom?
A body cavity derived from mesoderm and endoderm (only triploblasts). Animals that possess these are called pseudocoelomates
Triploblastic animals that lack a body cavity are called what?
Acoelomates
What are triploblasts that contain a true coelom called?
Coelomates
True or false: radial cleavage leads to protostomes and spirall cleavage leads to deuterostomes
False: spiral cleavage = protostomes & radial cleavage = deuterostomes
What are ecdysozoans?
Invertebrates that shed their exoskeleton through a process called ecdysis
What does arthropod mean?
Jointed feet
Most animals, and only animals have these types of genes, what are they?
Hox genes: highly conserved and it can produce a wide diversity of animal morphology
What animal most resembles the closest living relative to animals?
Choanoflagellates: protists that are closest living relatives of animals
How long ago did the common ancestor of all living animals live between?
700-770 MYA
What are the 3 forms of evidence that choanoflagellates are closely related o animals?
1) Cell morphology
2) Cell morphology unique to animal cells
3) DNA sequence homology
What is anatomy?
It’s the biological form of an organism
What is physiology?
The study of biological functions an organism performs
How does a jackrabbit keep from overheating?
Their hug are ears help them regulate their body heat by increasing or decreasing blood flow through their ears
What 2 characteristics affect the way an animal interacts w/ its env?
1) size
2) shape
What is the body plan of an animal programmed by?
It’s programmed by the genome
What are the 4 things physical laws constrain?
1) strength
2) diffusion
3) movement
4) heat exchange
As animals increase in size what needs to happen?
Their skeletons must be proportionally larger to support their mass
What does evolutionary convergence reflect?
It reflects how adaptations are similar due to similar environmental challenges
What is the rate of exchange of nutrient, waste products, and gases across cell membrane proportional to?
Rate of exchange is proportional to a cell’s surface area
What is the amount of exchange material proportional to?
Amount of exchange material is proportional to a cell’s volume
What are the 4 internal exchange surfaces of complex animals?
1) Digestive system
2) Circulatory system
3) Respiratory system
4) Excretory system
(Digestive system) What characteristic of the small intestines aid in exchange?
The lining of the small intestine has finger-like structures that expand the surface area for nutrient absorption
(Excretory system) What characteristics of the kidneys aid in exchange?
Blood is filtered across the surface of long, narrow blood vessels packed into ball-shaped structures
(Respiratory system) What characteristics of the lungs aid in exchange?
They are sponge-like and balloon-like which provides an expensive wet surface for gas exchange w/ the env
In vertebrates, what fluid fills the space b/w cells, and what does this fluid allow for?
Interstitial fluid which allows for the movement of material into and out of cells
How does a complex body plan help animals?
It helps with living in variable envs to maintain a relatively stable internal env
What is the order of the hierarchical organization of body plans?
Specialized cells -> tissues -> organs -> organ systems
What is an example of an organ that belongs to more than one organ system?
Pancreas
What are the 4 main categories of tissues?
1) Epithelial
2) Connective
3) Muscle
4) Nervous
Where is epithelial tissue found?
It cover the outside of the body and lines organs and cavities within the body and contains cells that are closely joined
What are the 3 shapes of epithelial cells?
1) cuboidal
2) columnar
3) squamous
What are the 3 arrangements of epithelial cells?
1) simple: single cell layer
2) stratified: multiple tiers of cells
3) pseudo-stratified: a single layer of cells of varying length
What do connective tissues do?
It mainly binds and supports other tissues
What are the 3 types of connective tissue fibres (all made of protein)?
1) Collagenous fibres: strength + flexibility
2) Elastic fibres: stretch and snap back
3) Reticular fibres: join connective tissue to adjacent tissues
What are the 2 types of cells in connective tissues?
1) Fibroblasts: secrete the protein of extracellular fibres
2) Macrophages: are involved in the immune system
What are the 6 major types of connective tissue in vertebrates?
1) Loose connective tissue
2) Fibrous connective tissue
3) Bone
4) Adipose tissue
5) Cartilage
6) Blood
What is muscle tissue responsible for?
Nearly all types of body movement
What do muscle cells consist of?
Filaments of the protein actin and myosin which together enables muscles to contract in response to nerve signals
What are the 3 groups of muscle tissue?
1) skeletal
2) smooth
3) cardiac
What are the 2 things nervous tissue contains and what do they do ?
1) Neurons/nerve cells: transmit nerve impulses
2) Glial cells/glia: help nourish, insulate, and replenish neurons
What do control and coordination within the body depend on?
They depend on the endocrine system and the nervous system
True or false: hormones act relatively slow, but can have long-lasting effects?
True
The information conveyed in the nervous system depends on what?
the information converted depends on a signal’s pathway, not the type of signal
Is neuron signal transmission fast or slow?
Very fast
What do regulators do?
They use internal control mechanisms to moderate internal change in the face of external environmental fluctuation
What do conformers do?
They allow their internal condition to vary with certain external changes
What do mechanisms of homeostasis do?
They moderate changes in the internal environment
What serves as stimulus in homeostasis?
For a given variable, fluctuations above or below a set point serve as a stimulus; these are detected by a sensor and trigger a response ad the response returns the variable to the set point
Is homeostasis a positive or negative feedback loop?
Negative feedback loop, since it returns a variable to a normal range
What do positive feedbacks do?
It amplifies a stimulus and doesn’t usually contribute to homeostasis in animals
Alterations in Homeostasis are caused by what?
Circadian Rhythm
Define acclimation?
Adjustment to a single environmental factor
Define acclimatization?
Adjustment to multiple factors
Define thermoregulation
The process by which animals maintain an internal temp within a tolerable range
How do endothermic animals generate heat?
Generate heat by metabolic activities; birds and mammals
How do ectothermic animals generate heat?
Gain heat from external sources; invertebrates, fishes, amphibians, and on avian reptiles
True or false: endotherms can’t maintain a stable body temp even in the face of large fluctuations in environmental temp
FALSE: they CAN maintain a stable body temp even in the face of large fluctuations in env temp; requires a lot of energy
True or false: in general, ectotherms tolerate greater variation in internal temps?
True
What are the 4 physical processes animals use to exchange heat?
1) Radiation
2) Evaporation
3) Convection
4) Conduction
What system in mammals is often involved in heat regulation?
integumentary system: skin, hair, and nails
What are 5 adaptations evolved to help animals thermoregulate?
1) Insulation
2) Circulatory adaptations
3) Cooling by evaporative heat loss
4) Behavioural responses
5) Adjusting metabolic heat production
What is the circulatory adaptation that marine mammals and birds evolved?
The arrangement of blood vessels in many marine mammals and birds allows for countercurrent exchange
What is countercurrent exchange?
Countercurrent heat exchangers transfer heat b/w fluids flowing in opposite directions and thereby reducing heat loss
How do many animals lose heat?
Through evaporation of water from their skin since sweating or bathing moistens the skin, helping to cool an animal down. Panting also increases the cooling effect in birds and many mammals
What behaviour by terrestrial invertebrates is used to minimize or maximize solar heat absorption?
They have postures that minimize or maximize absorption of solar heat
What behaviours in honey bees allows them to retain heat?
They huddle together during cold weather to retain heat
What is the definition of thermogenesis?
It’s the adjustment of metabolic heat production to maintain body temp
How is thermogenesis increased?
It’s increased by muscle activity such as moving or shivering
What is nonshivering thermogenesis (NST)?
it takes place when hormones cause mt to increase their metabolic activity
What is Brown Adipose Tissue (BAT) implicated in?
Burns energy to produce heat
What do ectotherms produce when temperatures are subzero and what does it do?
They produce “antifreeze” compounds to prevent ice formation in their cells
What region of the brain in mammals controls thermoregulation?
Hypothalamus; it triggers heat loss or heat generating mechanisms
What is bioenergetics?
the overall flow and transformation of energy in an animal
What does bioenergetics determine in animals and what does it relate to?
determines how much food an animal needs, and it relates to an animal’s size, activity and env
What is metabolic rate?
It’s the amount of energy an animal uses in a unit of time
What are the 3 things metabolic rate is determined by?
1) An animal’s heat loss
2) The amount of oxygen consumed or CO2 produced
3) Measuring energy content of food consumed and energy lost in waste products
What is the Basal metabolic rate (BMR)?
the metabolic rate of an endotherm at rest at a “comfortable” temp
What is the Standard metabolic rate (SMR)?
the metabolic rate of an ectotherm at rest at a specific temp
What 3 things do BMR and SMR both assume?
assume a nongrowing, fasting, and non-stressed animal
True or false: Ectotherms have much higher metabolic rates than endotherms of a comparable size
FALSE: Ectotherms have much lower metabolic rates than endotherms of a comparable size
What are 6 key factors that affect metabolic rates?
1) age
2) sex
3) size
4) activity
5) temp
6) nutrition
What is metabolic rate proportional to?
Metabolic rate is proportional to body mass to the power of 3/4 (m^3/4). Smaller animals have higher metabolic rates per gram than larger animals
What is torpor and what does it enable?
It’s a physiological state in which activity is low and metabolism decreases and it enables animals to save energy while avoiding difficult and dangerous conditions
What is hibernation?
It’s long-term torpor, that is an adaptation to winter cold and food scarcity
What is the name of summer torpor and what does it enable?
It’s called estivation and it enables animals to survive long periods of high temps and scarce water
Who exhibits daily torpor and what is it adapted to?
Daily torpor is exhibited by many small mammals and birds and seems adapted to feeding patterns
What 3 things do feedback circuits regulate?
1) digestion
2) energy storage
3) appetite
What is dentition in mammals specialized for?
different diets
What are the 4 classes of essential nutrients?
1) Essential amino acids
2) Essential Fatty acids
3) Vitamins
4) Minerals
What do micronutrients play roles in?
they play roles in enzyme function as substrates, coenzymes, and cofactors
How many amino acids do animals require and how many can they synthesize?
Require 20 and can synthesize about half and the remaining essential amino acids must be obtained from food
What 3 foods provide all essential amino acids and thus “complete” proteins?
1) meat
2) eggs
3) cheese
How do animals obtain essential fatty acids (can’t synthesize them)?
must be obtained from the diet and include unsaturated fatty acids (one or more double bonds).
True or false: Deficiencies in fatty acids are rare
TRUE
How many vitamins are essential for humans and what are the 2 groups that they fall under?
13 and they are grouped into 2 categories: Fat-soluble and water-soluble
What is scurvy?
a severe vitamin C deficiency
Which 5 fruits have the top highest vitamin C levels?
1) Guavas
2) Kiwifruit
3) Bell peppers
4) Strawberries
5) Oranges
What is the current daily value for vitamin C?
90mg
What is Hematomacrosis?
Causes Fe buildup without excessive Fe intake
VITAMINS (B9 onwards):
1) B9 = folic acid
2) B12 = cobalamin
3) C = ascorbic acid
4) A = Retinol
5) E = tocopherol
6) K = phylloquinone
How do cattle, deer and other herbivores prevent phosphorous deficiencies?
They consume concentrated sources of salt or other minerals; licking rocks or the ground
What are the 5 things that undernourished individuals will do?
1) use up stored fat and carbs
2) break down its own proteins
3) lose muscle mass
4) suffer protein deficiency of the brain
5) die or suffer irreversible damage
What are the 4 main ways of feeding?
1) Suspension feeding
2) substrate feeding
3) fluid feeding
4) bulk feeding
How do suspension feeders obtain their food?
Many aquatic animals are suspension feeders which sift small food particles from the water. Example = whales w/ baleen
How do substrate feeders obtain their food?
They are animals that live in or on their food. Example = caterpillars
How do fluid feeders obtain their food?
They suck nutrient-rich fluid from a living host. Example = black soldier fly which sucks nectar from flowers
How do bulk feeders obtain their food?
They eat relatively large pieces of food. Example = Lions, snakes, etc.
In enzymatic digestion, what does enzymatic digestion do?
It split bonds in molecules with the addition of water
Define elimination in the context of digestion?
Elimination is the passage of undigested material out of the digestive system
Most animals process foods in specialized compartments, why is this?
It reduces the risk of an animal digesting its own cells and tissues
What is intracellular digestion and give an example of an organism that digests through this process?
Food particles are engulfed by phagocytosis. Example = sponges digest their food entirely by this mechanism
Animals have. Digestive tube with 2 openings, mouth and anus, what is this digestive tube called?
Complete digestive tract or an alimentary canal
What does the mammalian digestive system consist of (2)?
1) an alimentary canal
2) accessory glands that secrete digestive juices through ducts
What are the 4 mammalian accessory glands that secrete digestive juices through ducts?
1) The salivary gland
2) The pancreas
3) The liver
4) The gallbladder
How is food pushed along during digestion?
It’s pushed along by peristalsis, rhythmic contractions of muscles in the wall of the canal
What regulates movement of material b/w compartments in digestion?
Vives called sphincters
What does the first stage of digestion consist of?
Occurs in the oral cavity where salivary glands deliver saliva to lubricate food, teeth chew food into smaller particles to then be mixed w/ salivary amylase which initiates breakdown of glucose polymers
What does saliva also contain and what is this made of?
Saliva also contains mucus which is a viscous mixture of water, salts, cells, and glycoproteins
What shape does the tongue shape food into?
The tongue shapes food into a bolus and helps with swallowing
Where does the pharynx (the throat) lead to?
The throat, or pharynx, is the junction that opens to both the esophagus and the trachea.
What part connects to the stomach?
The esophagus connects to the stomach
What part blocks entry to the trachea?
Swallowing causes the epiglottis to block entry to the trachea which lead to the lungs
When does coughing occur when you’re eating food?
Coughing occurs when the swallowing reflex fails and food or liquid reach the windpipe
The stomach secretes gastric juices which converts a meal into what?
Your meal becomes chyme
What is the pH of gastric juices and what does it do?
has a low pH of 2 which kills bacteria and denatures proteins
What are the 2 components of gastric juice?
1) HCl
2) Pepsin - protease that cleaves proteins into smaller peptides
What do parietal cells in the stomach do?
They secrete H+ ad Cl- separately into the stomach lumen