Biology Exam 2 Review Part 1

multicellularity, heterotrophy, internal digestion, and movement via nervous system

animals share these characteristics

asymmetry

cannot be divided along a plane to create similar halves

radial symmetry

body parts arranged along one main axis at the center of the body

bilateral symmetry

can be divided into mirror image left and right halves along a central axis

germ layers

primary layer of cells that forms during embryonic development

acoelomates

organisms with no true body cavity

pseudocoelomates

organisms with a body cavity (but not organs) that is lined with mesoderm cells

coelomates

organisms that have a body cavity and internal organs surrounded by mesoderm

metamerism

repeating body segments

polytomy

a node on a phylogeny where more than two lineages descend from a single ancestral lineage

hypothesis 1: “sponge sister”

nerves and muscles evolved after the ancestor of sponges branched off from the ancestor of all other animals

hypothesis 2: “ctenophore sister”

the ancestor of all animals had nerves, muscles, and a gut; the sponge lineage later lost these traits

diploblastic

having two cell layers: ectoderm and mesoderm

triploblastic

having three cell layers: ectoderm (skin, nervous system), mesoderm (muscles, bones), and endoderm (digestive tract, lungs)

protostome

the blastopore forms the mouth first; dorsal digestive tract and heart; ventral nerve cord

deuterostome

the blastopore forms the anus first; ventral digestive tract and heart; dorsal nerve cord

dorsoventral axis

top-bottom

anteroposterior axis

front-back

heterotrophs

animals that cannot produce energy without consuming organic compounds; have to eat other animals for energy

predation

feeding directly on other living animals

scavenging

feeding on animal carcasses

suspension feeding

capturing and feeding on food particles suspended in water

herbivory

eating plants and/or plant materials

omnivory

eating both plants and animals

symbiosis

intimate relationships between two species where one or both species benefits

mutualism

both organisms benefit; in some cases, if one leaves, the other might die

parasitism

one organism benefits at the cost of the other; some animals slowly feed off of nutrients from their host, often for long periods of time, without killing the host

commensalism

one organism benefits, with no effect on the other; most bacteria on your body have no effect on you

essential nutrients

molecules that animals need but cannot synthesize themselves

basal metabolic rate

the rate of energy consumption needed to fuel basic physiological processes

total metabolic rate

an animal’s BMR plus the energy required for physical activity, thermoregulation, digestion, etc

homeostasis

stability of internal bodily condition around the optimum for normal functioning

endotherms

must maintain a constant internal body temperature to function (ex. mammals and birds); metabolic rate will change as external temperature changes because the animal needs to thermoregulate

thermoneutral zone

the range of temperatures where metabolic rate is minimal and unchanging

ectotherms

can function at a range of internal body temperatures (ex. reptiles, fish, and insects); can tolerate extreme temperatures; metabolic rate rises as external temperature rises —> biochemical reactions are happening faster because of the environment

behavioral thermoregulation

ectotherms and endotherms can regulate temperature by moving to warmer/colder areas, shivering, etc.

controlled variable

the thing being controlled (ex. body temperature)

sensors

detect current levels of the controlled variable

control mechanism

uses information from sensors to activate the effectors (ex. the hypothalamus)

effectors

tissues/organs that can alter the controlled variable

negative feedback system

the system counteracts changes (ex. in temperature) from the target value (37C), known as the set point

cells

the functional units of cellular/molecular processes

tissues

collections of cells of similar types

organs

consist of two or more cell types with a defined structural/functional relationship to each other

multi-organ systems

consist of organs working together for a unified function (ex. digestion)

microbiome

active, diverse community of microbes that aid in digestion; mutualistic relationship

circulatory system

uses blood to transport important molecules like oxygen and food compounds (fatty acids, glucose); serves as a regulatory system for blood glucose

hibernation

minimize activity, reduce metabolic processes to survive cold; often seasonal, actually lowers body temp, breathing, heart rate, and metabolism

regional hypothermia

appendages can be much colder than the body core when it would be too energetically costly to heat the entire body equally

countercurrent exchange

arteries and veins are touching; heat is transferred from warmer arteries into the cooler veins before it is lost in the distal appendage

arteries

move oxygenated blood from the lungs

veins

move deoxygenated blood from appendages

loops of Henle

these in the kidneys help to retain water

osmotic pressure

concentration of dissolved material in a solution that determines the direction of water movement

osmosis

water moves from low to high osmotic pressure

iso-osmotic

two solutions have the same osmotic pressures

hyper-osmotic

a solution having higher osmotic pressure (more solutes) than another solution

hypo-osmotic

a solution having lower osmotic pressure (fewer solutes) than another solution

hyper-osmotic regulator (freshwater fish)

these fish don’t drink water; water passes over the gills, water flows in through osmosis, and salt diffuses out

hypo-osmotic regulator (saltwater fish)

these fish drink water and actively secrete salts; water passes over the gills, water is lost through osmosis, and salt moves in by diffusion

salt glands

many air-breathing vertebrates that live in/near the sea have these which use ATP to dispose of excess salts

phenotypic plasticity

one genotype can express different phenotypes depending on environmental conditions

tradeoffs

investing in one trait likely leaves you less resources to invest in others

circadian rhythm

biological clock on a 24 hour cycle

evaginated

gills are ( ………), pushed out of body and surrounded by water

invaginated

lungs are ( ……..), folded into the body and contain the air

operculum

the flap covering the gills

more

countercurrent gas exchange is ( ……) efficient than cocurrent gas exchange

trachea

unique breathing apparatus consisting of long, branching tubes that lead deep into the body

spiracles

open holes that connect the trachea to the environment and allow for passive diffusion of O2; not a very efficient method of breathing

open

insects have an (…….. ) circulatory system

air sacs

birds have these to fill up much of the body and ventilate the lungs; do not participate in gas exchange

unidirectionally

air flows through birds’ lungs ( …….), during inhalation and exhalation

gross anatomy

anatomy you can see with the naked eye; includes the primary bronchus and secondary bronchus

alveoli

principle site of gas exchange; thin walls, blood very close to O2

epithelia

O2 must cross through two of these thin tissues around structures in the body

diaphragm muscle

expands the chest cavity and brings air into the lungs

bulk flow

large-scale movement of air into the body

diffusion

the small-scale movement of O2 across membranes; movement of molecules from areas of high to low concentration

tidal volume

amount of air brought into lungs

0.5 liters

resting tidal volume

5 liters

maximum tidal volume; maximum amount of air inhaled per breath

medulla oblongata

part of the brain responsible for stimulating the muscles involved in breathing; increases breathing to combat the rise in blood CO2

acidic

increase in CO2 makes blood more ( ……….)