USAP Science Resource Guide: An Introduction to Animal Behavior and Migration

Comprehensive practice flashcard set covering foundational principles of animal behavior, physiology, learning, sociality, and migration from the 2026–2027 USAP Science Resource Guide.

What are the three criteria an organism must meet to be classified as an animal?

1) Feed on organic matter; 2) Be able to move from one place to another; 3) Be multicellular with eukaryotic cells containing membrane-bound organelles and produce collagen.

Why are plants excluded from the kingdom Animalia under the feeding criterion?

Plants produce their own food by utilizing sunlight rather than feeding on organic matter.

How does the requirement for movement apply to sessile or slow-moving animals?

Animals must have the capacity to move the entire organism from one place to another, even if only during certain lifecycle phases or at slow speeds.

What defining structural protein is produced by animal cells to hold them together?

Collagen

Why are fungi not classified as animals despite being multicellular eukaryotes that ingest organic matter?

Fungi produce chitin rather than collagen to provide structural support to their cells.

Why are protists excluded from the animal kingdom?

Protists are usually unicellular and do not produce collagen.

What anatomical traits uniquely define mammals?

Possessing a spinal cord and brain, producing milk from mammary glands, having hair, and possessing $3$ middle ear bones.

What does the term "viviparous" mean regarding mammalian reproduction?

Giving birth to live young rather than laying eggs.

Which two monotremes are exceptions to the viviparous rule by laying eggs?

The platypus (Ornithorhynchus anatinus) and the echidna (Tachyglossidae).

What is the evolutionary function of the three middle ear bones in mammals?

They transmit sound vibrations from the ear into messages in the brain.

What is the difference between oviparous and ovoviviparous reproduction?

Oviparous animals reproduce by laying eggs, whereas ovoviviparous animals give live birth to offspring that developed and hatched internally.

What substance makes up the internal skeletal support structures of certain fish instead of bone?

Cartilage

Which family of flightless birds spends most of its life in or around water?

Penguins (Spheniscidae)

How is the mudskipper (Periophthalmus gracilis) adapted to breathe in muddy intertidal environments?

It uses modified gill structures to extract oxygen from both the air and water.

How do amphibians obtain oxygen in wet environments in addition to using their lungs?

They breathe cutaneously through their skin.

What anatomical features differentiate insects from arachnids?

Insects have $3$ body segments and $6$ legs; arachnids have $2$ body segments and $8$ legs.

What circulatory fluid is pumped through the open circulatory system of arthropods to oxygenate organs?

Hemolymph

What is the Goliath birdeater (Theraphosa blondi)?

A large South American tarantula known to catch and kill birds as a primary food source.

What is the estimated ratio of living arthropods relative to each human on Earth?

$1\text{ billion}$ arthropods for every single human being.

How do sessile adult sea sponges fulfill the movement criterion of animals during development?

They possess a free-swimming larval phase before settling permanently onto rocky underwater surfaces.

What microscopic animal, capable of withstanding extreme temperatures and radiation, is shown in this image?

Tardigrade (water bear, phylum Tardigrada)

Which animals are known to utilize photosynthesis to acquire energy directly from the sun?

Certain species of sea slugs

What is the broad definition of "behavior" in animals?

All the ways animals interact with other organisms, internal signals, and the physical environment.

What is an internal stimulus, and what common thermoregulatory behavior illustrates it?

A sensation originating from within an animal's body; shivering in response to a drop in internal body temperature.

How do cats typically respond to the external stimulus of seeing a mouse?

By crouching down and expanding their pupils in preparation to hunt.

What primary evolutionary advantage does group living provide against predation and food scarcity?

It increases the number of eyes vigilant for predators and looking for food.

Under what physiological condition are animals most likely to engage in play behavior?

When experiencing low levels of stress.

What evolutionary tradeoff is illustrated by the peacock's long, brightly colored feathers?

They increase attraction to females for mating but make the male more visible to predators and less able to escape.

What is the biological definition of ecology?

The study of how living organisms interact with their environment to maximize their chances of survival and reproduction.

What are the six ecological levels of organization from smallest to broadest?

Organism, population, community, ecosystem, biome, and biosphere.

What is an ecological community?

An interacting group of multiple populations of different species inhabiting the same area.

What distinguishes an ecosystem from a biological community?

An ecosystem includes living organisms (populations) along with nonliving physical aspects such as water, soil, and sunlight.

What is a keystone species?

A species whose presence is vital to the stability and survival of an entire ecosystem, without which the ecosystem would collapse.

Who established the modern standardized taxonomy system, and in what year?

Carl Linnaeus in $1735$.

Why did Carl Linnaeus choose Latin for taxonomic nomenclature?

Latin is a dead language, meaning its grammatical and lexical rules remain consistent over time.

What are the eight primary taxonomic ranks from broadest to most specific?

Domain, kingdom, phylum, class, order, family, genus, and species.

What are the formatting rules for writing an animal's binomial scientific name?

It consists of an italicized genus with the first letter capitalized followed by an italicized species name in all lowercase letters.

What does an internal node on a phylogenetic tree represent?

The last common ancestor shared by the taxa branching off from that point.

What is a divergence event in evolutionary biology?

The point at which two populations accumulate sufficient genetic differences that they can no longer interbreed.

What is LUCA, and when is it theorized to have existed?

The Last Universal Common Ancestor; a theoretical single-celled organism believed to have lived over $4.2\text{ billion}$ years ago.

When do fossil records show the earliest multicellular ocean animals lived, and what did they resemble?

Approximately $910\text{ million}$ years ago; they resembled modern sponges and jellyfish.

What is the oldest known air-breathing land animal, and who discovered it?

Pneumodesmus newmani; discovered in Scotland in $2004$ by amateur paleontologist Mike Newman.

What oldest known land animal is reconstructed in this image?

Pneumodesmus newmani (P. newmani)

When did the first vertebrate animals with bones and spines transition onto land?

Approximately $375\text{ million}$ years ago.

What is the oldest known mammal species, and when did it live?

Brasilodon (Basilodon), a small furry rodent-like creature that lived approximately $225\text{ million}$ years ago.

What percentage of mammal species survived the Cretaceous mass extinction that eliminated the dinosaurs?

Approximately $7\%$

What is the biological definition of evolution?

The total genetic and phenotypic change in a population of organisms over time.

What does evolutionary "fitness" specifically measure?

An individual's success at surviving and reproducing fertile offspring in its environment.

Which insect species illustrated rapid, human-induced natural selection during the Industrial Revolution?

Peppered moths

Why did the dark morph of the peppered moth become dominant in England during the Industrial Revolution?

Coal soot darkened tree trunks, allowing dark moths to camouflage from predatory birds while light spotted moths were eaten.

Who formulated the theory of natural selection in the late 1830s?

Charles Darwin

What is the distinction between positive and negative selective pressures?

Positive selective pressures promote the inheritance of adaptive traits; negative selective pressures eliminate disadvantageous traits from a population.

Why are animals physically limited from growing exponentially larger?

Gravitational limits, tissue oxygen transport limits, and the metabolic requirement to obtain more energy than is exerted.

What environmental factor allowed insects and dinosaurs to achieve massive sizes during the Mesozoic era?

An atmosphere with significantly higher concentrations of available oxygen.

Why are populations with low reproductive rates more vulnerable to rapid environmental changes?

Fewer generations and offspring result in less genetic variation and slower generation of adaptive mutations.

What is an evolutionary "selfish" behavioral strategy?

A behavior that prioritizes the immediate survival of the individual over others, ensuring the individual lives to reproduce again.

What is the theory of kin selection?

The evolutionary strategy where individuals risk their own fitness to assist genetic relatives, increasing the survival of shared genes.

How do non-breeding Florida scrub jays exhibit kin selection?

They remain near their natal territory to help their parents protect nests and raise younger siblings.

Which ancient Egyptian deity was worshiped as a cat or lion beginning around 2800 BCE?

Bastet

How did Aristotle describe the classification of living things around 300 BCE?

As a static hierarchical scale of complexity where animals ranked below humans but above plants.

What is ethology?

The scientific study of animal behavior.

What landmark 1859 book by Charles Darwin promoted the study of behavior as an inherited trait?

On the Origin of Species

Which three pioneering ethologists jointly received the Nobel Prize in Physiology or Medicine in 1973?

Karl von Frisch, Konrad Lorenz, and Nikolaas Tinbergen.

What is imprinting, as discovered by Konrad Lorenz?

A rapid developmental learning process occurring during a critical period where young animals fixate on the first moving object they see as their parent.

What sensory communication discovery is credited to Karl von Frisch?

Translating the "waggle dance" used by honeybees to communicate nectar source locations.

What is applied animal behavior?

An approach that uses behavior research to design interventions and treatments that improve the welfare of animals.

What are Tinbergen's Four Questions used to explain animal behavior?

Function (Adaptation), History (Evolution), Cause (Mechanism), and Development (Ontogeny).

In Tinbergen's framework, what does the question of "Function" examine?

How a behavior contributes to the survival, fitness, and reproductive success of an animal.

In Tinbergen's framework, what does the question of "History" investigate?

How a behavior evolved across ancestral species over evolutionary time.

In Tinbergen's framework, what does the question of "Cause" evaluate?

The immediate internal physiological mechanisms or external sensory triggers eliciting a behavior.

In Tinbergen's framework, what does the question of "Development" address?

How a behavior develops or changes over an individual's lifetime through learning or genetic maturation.

What is anthropomorphism, and why is it a risk in animal behavior research?

Viewing animal actions through the lens of human experience; it causes observer bias and incorrect conclusions about emotional intent.

How does a chimpanzee's bared-teeth display contrast with a human smile?

Chimpanzees bare their teeth as a submissive sign of fear, whereas humans do so to convey happiness.

What is a natural manipulation in an observational behavior study?

An unprompted environmental shift, such as a major wildfire, blizzard, or pandemic, whose effects researchers monitor on wildlife.

What is the function of a control group in laboratory behavior experiments?

To serve as an unmanipulated baseline to determine direct cause-and-effect relationships with the experimental variable.

What is an ethogram?

A standardized inventory of detailed descriptions used to objectively measure and quantify behaviors.

What is inter-rater reliability?

A measure of consistency reflecting how similarly two or more independent observers score the same behaviors using identical criteria.

What role does dopamine play across almost all animal taxa, illustrating structural conservation?

It regulates feeding behaviors and locomotion.

What are the two primary divisions of the vertebrate nervous system?

The central nervous system (brain and spinal cord) and the peripheral nervous system.

What are the functional cells of the nervous system, and what chemicals mediate their communication?

Neurons; neurotransmitters.

How do regenerative capacities differ between neurons in the CNS and PNS?

Central nervous system neurons typically do not regenerate, whereas peripheral nerves have the capacity to regrow and repair.

What is the difference between sensation and perception?

Sensation is the physical detection of stimuli by sensory receptors; perception is the brain's interpretation of those signals using memory and experience.

Which sensory capability do toothed whales, such as orcas and dolphins, completely lack?

The sense of smell (olfaction).

What are human tetrachromats?

Individuals possessing a fourth type of retinal cone cell that allows them to detect colors invisible to trichromats.

When did the vertebrate nervous system evolve from ancestral invertebrate systems?

Approximately $500\text{ million}$ years ago.

What are the two functional components of the vertebrate peripheral nervous system?

The somatic nervous system and the autonomic nervous system.

What are nociceptors?

Specialized somatosensory pain receptors that detect harmful pressure and temperature stimuli.

How does a spinal reflex arc function when a nociceptor detects tissue injury?

The nociceptor relays signals directly to the spinal cord, which immediately commands muscle withdrawal before the brain perceives pain.

What is proprioception?

The sensory feedback from neurons in muscles and joints that informs the brain of body position and balance in space.

What distance must two pressure points be separated on the human back to be perceived as two distinct points?

More than $35\,mm$

What are the two operational branches of the autonomic nervous system?

The sympathetic nervous system and the parasympathetic nervous system.

How does the sympathetic nervous system prepare the body during acute threats?

It triggers "fight or flight" responses, increasing heart rate, respiration, and immune readiness while suppressing digestion and reproduction.

What is the function of the parasympathetic nervous system?

It activates "rest and digest" processes, decreasing heart rate and returning physiological systems to a calm state of balance.

What health issue can result from long-term sympathetic activation and continuous system switching?

Autoimmune diseases caused by impaired immune inflammation control.

What is the blood-brain barrier?

A selective cellular layer around brain blood vessels that permits entry of oxygen and nutrients while blocking pathogens and toxins.

Why is the sea slug (Aplysia californica) widely studied in neuroscience?

It has exceptionally large neurons that can be observed and mapped without a microscope.

What type of nervous organization characterizes cnidarians like hydras and jellyfish?

A decentralized nerve net lacking a centralized brain.

Which invertebrates possess the most complex nervous systems and largest brain-to-body ratios?

Cephalopods (such as octopuses and squids).

What is the difference between endogenous and exogenous hormones?

Endogenous hormones are produced internally by endocrine glands; exogenous hormones originate from outside sources like food or medications.

How can oxytocin act as both a neurotransmitter and a hormone?

It functions as a neurotransmitter when released in synaptic clefts in the brain, but acts as a hormone when circulated via blood to target organs.