ACADEC Section 1 Animal Behavior

Animal

A living organism that feeds on organic matter, can move from place to place, and has multicellular eukaryotic cells that produce collagen

Fungi vs. animals

Fungi consume organic matter but produce chitin instead of collagen

Protists vs. animals

Most protists are unicellular and cannot produce collagen

Mammals

Animals with spinal cords, brains, hair, milk-producing mammary glands, and three middle-ear bones

Viviparous

Giving birth to live young

Monotremes

Egg-laying mammals, such as platypuses and echidnas

Oviparous

Reproducing by laying eggs

Ovoviviparous

Offspring develop and hatch internally before being born alive

Major vertebrate groups

Mammals, reptiles, fish, amphibians, and birds

Amphibian respiration

Amphibians can breathe through their skin and lungs

Arthropods

Animals with exoskeletons, including insects and arachnids

Insects

Arthropods with three body segments and six legs

Arachnids

Arthropods with two body segments and eight legs

Exoskeleton

External skeleton that supports and protects an animal, arthopods

Hemolymph

Fluid in the open circulatory system of arthropods

Arthropod diversity

About 80–85% of known animal species are arthropods

Hunting response

Example of behavior caused by an external stimulus

Benefits of group living

More individuals can watch for predators and locate food

Play behavior

Behavior that can help animals learn skills needed later in life

Mating display

Behavior used to attract mates that may also increase vulnerability to predators

Ecological levels of organization

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

Ecosystem

A community and its interactions with the physical environment

Biome

Large area containing multiple ecosystems

Biosphere

All environments and life found on Earth

Effects of high animal density

Can increase competition for food, territory, and mates but can also increase protection from predators

Keystone species

Species that is vital to an ecosystem and whose removal can cause major ecosystem disruption or collapse

Taxonomy

Science of classifying organisms

Binomial nomenclature

Two-part Latin scientific naming system for species

Scientific name

Italicized genus with a capital first letter followed by an italicized lowercase species name

Taxonomic order

Domain → kingdom → phylum → class → order → family → genus → species

Phylogenetic tree

Diagram showing evolutionary relationships among organisms

Internal node

Point where branches meet, representing a last common ancestor

Last common ancestor

Most recent ancestral group shared by two organisms

Divergence event

Point when populations become sufficiently genetically different to become separate species

Branch length

Indicates the amount of genetic change

Relatedness on a phylogenetic tree

Organisms sharing a more recent common node are more closely related

LUCA

Last Universal Common Ancestor

First multicellular animals

Believed to have resembled early sponges or jellyfish, fossil evidence indicates animals existed in ancient oceans as far back as about 910 million years ago

P. newmani

Millipede-like organism considered the first known animal to breathe oxygen and walk on land, about 420 million years ago

Species

Group whose members generally cannot produce fertile offspring with members of another species

Selective pressure

Environmental factor that affects which traits are favored or removed

Survival of the fittest

Individuals with traits best suited to their environment are more likely to survive and reproduce

Evolution is not intentional

Organisms do not choose which traits to evolve

Mutation

Random change in genetic code that can introduce variation

Adaptive mutation

Mutation that improves an organism's ability to survive or reproduce

Genetic variation and evolution

Evolution requires genetic variation for natural selection to act upon

Reproductive rate and evolution

Faster reproduction can produce genetic changes more rapidly

Evolutionary limitations

Physics, gravity, oxygen availability, energy availability, and insufficient genetic variation can limit evolution

Instinctual behavior

Behavior controlled primarily by genes

Learned behavior

Behavior acquired through experience or environmental influences

Selfish behavior

Behavior that prioritizes the survival and reproduction of the individual

Kin selection

Evolutionary process in which helping relatives can increase the survival of shared genes

Social behavior evolution

Requires complex sensory and brain systems to recognize and interact with others

Ethology

Scientific study of animal behavior

Charles Darwin

Scientist who connected animal behavior with evolution and natural selection on the Origin of Species

Konrad Lorenz

Ethologist known for research on imprinting

Imprinting

Learning to recognize a parent or important stimulus during a critical developmental period

Niko Tinbergen

Ethologist known for studying animal behavior and developing the Four Questions

Karl von Frisch

Ethologist known for research on animal communication, sexual selection, and honeybee dances

Applied animal behavior

Using animal behavior research to improve animal welfare and wellbeing

Tinbergen's Four Questions

Function, history/evolution, cause/mechanism, and development/ontogeny

Function/adaptation

How a behavior improves survival or reproductive success

History/evolution

How a behavior evolved and what its origins are

Cause/mechanism

What internal or external factors trigger a behavior

Development/ontogeny

How a behavior develops through genes, learning, and experience

Anthropomorphism

Interpreting animal behavior through the lens of human emotions, traits, or experiences

Problem with anthropomorphism

Human interpretations may not accurately represent an animal's actual behavior or context

Observational study

Research that records animal behavior without directly manipulating variables

Limitation of observational studies

They can show associations but cannot establish direct cause and effect alone

Natural manipulation

Naturally occurring environmental change used to study its effects on behavior

Artificial manipulation

Controlled environmental change intentionally created by researchers

Laboratory experiment

Controlled study in which researchers manipulate variables and measure behavioral responses

Advantage of laboratory studies

Greater control over variables allows stronger conclusions about cause and effect

Limitation of laboratory studies

Artificial conditions may not accurately represent behavior in the wild

Ethogram

Standardized, detailed description of animal behaviors used to quantify behavior

Purpose of an ethogram

Allows researchers to identify and measure behaviors consistently

Inter-rater reliability

Degree to which independent observers consistently identify the same behaviors

Machine learning in behavior research

Uses algorithms to detect and measure behaviors according to defined visual criteria

Behavioral genetics

Study of how genes and environmental factors interact to influence behavior

Gene and behavior

Having a gene associated with a behavior does not guarantee that the behavior will occur

Gene expression

Process by which genetic information is used and can change in response to experiences or environmental factors

Comparative biology

Comparing organisms and their structures or behaviors to understand how traits evolved

Dopamine

Molecule found across many animals that helps regulate movement and feeding

Studying extinct animals

Researchers infer behavior using fossils, physical structures, and comparisons with living relatives

Genetic similarity and relatedness

Greater shared DNA generally indicates closer evolutionary relationships

Behavioral similarity and relatedness

Similar behavior can suggest relatedness but can be misleading because unrelated species can independently evolve similar behavior