I band The area near the edge of the sarcomere where there are only thin filaments.

ileumThe last of three sections of the small

intestine primarily involved in the absorption of nutrients and water.

imaginal diskAn island of undifferentiated cells in an

insect larva, which are committed (determined) to form a particular organ

during metamorphosis to the adult.

immune adherence

The collective action of antibodies, complement, and phagocytes. Microbes coated with antibodies and complement proteins adhere to blood vessel walls, making the pathogens easier prey for

phagocytic cells circulating in the blood.

immunizationAlso called vaccination, it is the exposure of

an organism to agents that can no longer cause disease but retain the ability to act as

antigens, thereby stimulating an immune response and immunological memory.

immunoglobulin (Ig)

imperfect fungi

imprinting

invitro fertilization

invitro mutagenesis

inclusive fitness

incomplete dominance

incomplete flower

incomplete metamorphosis

incus

indeterminate cleavage

indeterminate growth

individualistic hypothesis

induced fit

inducer

induction

inflammatory response

ingestion

ingroup

inheritance

inhibit

ingroup

inheritance

inhibit

inhibiting hormone

inhibitory postsynaptic potential

(IPSP)

inner cell mass

inner ear

inositol triphosphate (IP3)

Insecta

insecticide

insertion

insertion sequence

insight learning

insulin

insulinlike growth factors

integral protein

integration

integrin

integuments

interactive hypothesis

intercalated discs

interferon

interleukin-1 (IL-1)

interleukin-2 (IL-2)

intermediate filament

internal fertilization

interneuron

internode

interoreceptor

interphase

intersexual selection

interspecific competition

interstitial cells

interstitial fluid

intertidal zone

intracellular digestion

intrasexual selection

intrinsic rate of increase

introgression

intron

invagination

inversion

invertebrate

involution

ion

ionic bond

ionic compound

islets of Langerhands

isogamy

isomer

isomorphic

isopods

isotonic

isotope

iteroparity

jejunumThe middle section of the small intestine

primarily involved in the absorption of nutrients and water.

joule (J) A unit of energy: 1 J50.239 cal; 1 cal54.184 J.

juvenile hormone (JH)A hormone in arthropods, secreted by the corpora allata glands, that promotes the

retention of larval characteristics.

juxtaglomerular apparatus

A specialized tissue located near the afferent arteriole that supplies blood to the

glomerulus.

juxtamedullary nephrons

Nephrons with well-developed loops of Henle that extend deeply into the renal

medulla.

karyogamy

karyokinesis

karyotype

ketone

keystone predator

keystone species

kilocalorie (kcal)

kin selection

kinesis

kinetic energy

kinetochore

kinetoplastid

kingdom

kingdom Plantae

kingdom Streptophyta

kingdom Viridiplantae

Koch’s postulates

Krebs cycle

K-selection

labia majora

labia minora

labor

lactation

lactation

lacteal

lactic acid fermentation

lacunae

lagging strand

lancelet

landmark

landscape

landscape ecology

larva

larynx

lateral geniculate nuclei

lateral inhibition

lateral line system

lateral meristem

lateral roots

law of independent assortment

law of segregation

leading strand

learning

lens

lepidosaurs

leukocyte

Leydig cell

lichen

life history

life table

ligament

ligand

ligand-gated ion channel

ligand-gated ion channel receptor

light chains

light microscope (LM)

light reactions

lignin

limbic system

limnetic zone

linkage map

linked genes

lipase

lipid

lipoprotein

littoral zone

liver

liverworts

loams

local regulator

locomotion

locus

logistic population growth

long-day plant

long-term depression (LTD)

long-term memory

long-term potentiation (LTP)

loop of Henle

loose connective tissue

lophophorate animals

lophophore

Lophotrochozoa

low-density lipoprotein (LDL)

lungs

luteal pahse

lutenizing hormone (LH)

lymph

lymph node

lymphatic system

lymphocyte

lymphomas

lysogenic cycle

lysosome

lytic cycle

M phase

macroevolution

macromolecule

macronutrient

macrophase

major histocompatibility

complex (MHC)

malignant tumor

malleus

malnourished

malpighian tubule

Mammalia

mammary glands

mandibles

mantles

mantle city

map units

mark-recapture method

marsupial

mass number

mast cell

maternal effect genes

matrix

matter

mechanoreceptor

medulla

medusa

magapascal (MPa)

megaphylls

megaspores

meiosis

meiosis I

meiosis II

melanocyte-stimulating hormone

melatonin

membrane attack complex (MAC)

membrane potential

memory cell

meniscus

menstrual cycle

menstrual flow phase

menstruation

meristem

meristem identity genes

meroblastic cleavage

mesentery

mesoderm

mesohyl

mesophyll

mesophyll cell

mesotrophic

messenger RNA (mRNA)

metabolism

metamorphosis

metanephridium

metaphase

metaphase plate

metapopulation

metastasis

methanogen

microclimate

microevolution

microfilament

micronutrient

microphylls

microspores

microtubule

microvillus

midbrain

middle ear

middle lamella

mimicry

mineral

mineral nutrients

mineralocorticoid

minimum dynamic area

minimum viable population size (MVP)

mismatch repair

missense mutation

mitochondrial matrix

mitochondrion

mitosis

mitotic phase

mitotic spindle

model organism

modern synthesis

molarity

mold

mole

molecular clocks

molecular formula

molecular weight

molecule

molting

monoclonal antibody

monocot

monoculture

monocyte

monoecious

monogamous

monohybrid

monomer

monophyletic

monosaccharide

monosomic

monotreme

morphogen

morphological species concept

morphospecies

morula

mosaic

mosaic development

mosaic evolution

motor division

motor neuron

motor output

motor unit

movement corridor

MPF (M-phase-promoting factor)

mucous membrane

Müllerian mimicry

multifactorial

multigene family

multiple fruit

multiregional hypothesis

muscle spindle

muscle tissue

mutagen

mutagenesis

mutant phenotypes

mutation

mutualism

mycelium

mycorrhiza

mycosis

myelin sheath

myofibril

myofilaments

myoglobin

myosin

myotonia

NAD+

NADH

NADP+

natural family planning

natural killer (NK) cell

natural selection

natural theology

negative feedback

negative pressure breathing

nematocysts

nephron

neritic zone

nerve

nerve net

nervous tissue

net primary production (NPP)

neural crest

neural tube

neurohypophysis

neuron

neuropeptides

neurosecretory cells

neurotransmitter

neutral variation

neutralization

neutron

nuetrophil

niche

9:3:3:1 ratio

nitric oxide

nitrogen fixation

nitrogenase

nitrogen-fixing bacteria

nociceptor

node

nodes of Ranvier

nodules

noncompetitive inhibitor

noncyclic electron flow

noncyclic photophosphorylation

nondisjunction

nonequilibrium model

nonpolar covalent bond

nonsense mutation

nonshivering thermogenesis

norepinephrine

norm of reaction

notochord

nuclear envelope

nuclear lamina

nuclease

nucleic acid

nucleic acid hybridizationi

nucleic acid probe

nucleoid

nucleoid region

nucleolus

nucleoside

nucleosome

nucleotide

nucleotide excision repair

nucleus

obligate aerobe

obligate anaerobe

oceanic pelagic biome

oceanic zone

old growth

olfactory receptors

oligodendrocytes

oligotrophic lake

ommatidia

omnivore

oncogene

one gene-one polypeptide hypothesis

ontongeny

oogamy

oogenesis

open circulatory system

operant conditioning

operator

operculum

operon

opportunistic

opposable thumb

opsin

opsonization

optic chiasm

optimal foraging theory

oral cavity

order

organ

organ of Corti

organ system

organelle

organic chemistry

organ identity gene

organism

organismal ecology

organogenesis

orgasm

origins of replication

osculum

osmoconformer

osmolarity

osmoregulation

osmoregulator

osmosis

osmotic pressure

Osteichthyes

osteoblasts

osteons

ostracoderm

outer ear

outgroup

out of Africa hypothesis

oval window

ovarian cycle

ovary

overnourishment

oviduct

oviparous

ovoviviparous

ovulation

ovule

ovum

oxidation

oxidative phosphoylation

oxidizing agent

oxytocin