BI107 Test 3

Life History

sequence and duration of stages an organism passes through during its life

What is life history shaped by?

the way an organism divides its energy and resources between growth, reproduction, and survival

Maintenance

metabolism, other bodily functions, getting more resources

Defense

physical and chemical defenses

Growth

the increase in size and mass of an organism

Reproduction

producing offspring, caring for offspring

Principle of Allocation

resources cannot be used for two functions simultaneously

r-selected species life history traits

many, small offspring; little to no parental care; short growth period before reproductive maturity

k-selected species life history traits

few, large offspring; more parental care; long growth period before reproductive maturity

Peak Population Year

2086

Community Ecology

the study of the interactions between species in communities

Niche (physical)

the physical and biological environment a species occupies

Niche (role)

what a species does in a community

How do realized niches compare to fundamental niches?

realized niches are smaller

Competition

negative, negative; organisms compete for the same limited resources

Parasitism

positive, negative; an organism eats, but typically does not kill, another organism

Predation

positive, negative; one organism kills and eats another

Herbivory

postive, negative; an herbivore eats a producer

Mutualism

positive, positive; both organisms benefit from the interaction

Commensalism

positive, neutral; one organism benefits, the other is not impacted

Intraspecific Competition

between individuals of the same species

Interspecific Competition

between individuals of different species

Resource Partitioning

an evolutionary and behavioral process where competing species use limited resources (like food, space, or light) in different ways, places, or times.

Character Displacement

change in a character state to favor the use of a different resource, reducing competition between two competing species

Evolutionary Arms Race

a series of reciprocal adaptations between two species that try to outcompete each other

Keystone Species

vital to the health of the community

Ecosystem Engineers

a keystone species that creates or maintains habitat for other species

Species Richness

total number of different species in the community

Relative Abundance (Eveness)

proportion of each species of the total individuals in the community

Shannon Diversity Index

Higher H values indicate more diversity; takes into account richness and eveness

Functional Diversity

the variety of functions species perform

Structural Diversity

physical arrangement, shape, and volumetric capacity of biotic components

What is the relationship between productivity and species richness

it increases but not linearly

Trophic Cascade

changes at one trophic level in an ecosystem have indirect and direct effects, affecting multiple other trophic levels

Theory of Island Biogeography

the number of species on an island represents an equilibrium between the rate at which species immigrate to the island and the rate at which resident species go locally extinct

What does species richness on an island depend on?

colonization, distance; extinction, island size

Disturbance

any event that results in changes to population size or community composition

Succession

the process by which natural communities replace one another over time

Primary Succession

the step-by-step process of ecosystem development that starts in a completely lifeless, barren area lacking soil

Secondary Succession

the process of ecosystem regrowth that occurs after a major disturbance—such as a wildfire, flood, or logging—destroys existing vegetation but leaves the soil and its nutrients intact

Destruction

less area for species to exist, reduced resource availability

Degradation

shift in conditions makes habitat less suitable

Fragmentation

edge effects, smaller population sizes may mean less genetic diversity

What conservation strategy is used to combat habitat fragmentation?

wildlife corridors

Fundamental Niche

the locations where it is physically possible for a particular species to live

Realized Niche

the locations an organism actually occupies

Native Species

species that have evolved in the habitat for a long time

Exotic Species

evolved somewhere else and introduced to an area

Invasive Species

exotic species that outcompete native species for space and other resources, in some cases taking over areas and eliminating native species entirely

Functional Group

a collection of species that have a distinctive structural or functional role in an ecosystem

Resilience

the ability to recover from disturbance

Ethology

the science of how and why animals behave

Do Plants Behave?

Yes, with growth responses and physiological responses

What are Tinbergen’s Four Questions?

Causation, Development, Function, Evolution

Proximate Questions

“how” questions, the immediate mechanisms that trigger an action, such as neurological processes, hormones, genes, and early development, rather than its evolutionary purpose

Ultimate

“why” questions, asks why a behavior exists in an evolutionary context. It focuses on the adaptive value of a behavior (how it helps the animal survive and reproduce) and its evolutionary history

Causation Question

what are the stimuli that elicit the behavioral response? How might the behavior have been modified by recent learning?

Development Question

How does the behavior change with age? What early experiences are needed for the behavior to be shown?

Function Question

How does the behavior impact the animal’s chances of survival and reproduction?

Evolution Question

How does the behavior compare with similar behavior in related species? How might it have arisen?

Innate Behavior

hardwired into the organism; not learned

Learned Behavior

results from environmental learning

Reflex

involuntary and rapid response to stimulus

Kinesis

undirected movement in response to stimulus

Taxis

directed movement towards or away from stimulus

Fixed Action Patterns

species-specific instinctive behaviors that are performed the same way each time

Habituation

learning to ignore a repetitive non-dangerous stimulus

Imprinting

rapid learning at a particular age or life stage, typically just after birth or hatching

Conditioned Behavior

a stimulus that becomes associated with a consequence

Classical Conditioning

pairs a naturally occurring, automatic reflex with a previously neutral stimulus

Operant Conditioning

alters voluntary behavior through the use of reinforcements (which encourage behavior) and punishments (which discourage behavior)

Cognitive Learning

manipulation of information using mental processes, such as thinking, problem-solving, and decision-making

Foraging

searching for good resources; optimal foraging behaviors maximize energy gain and minimize energy expenditure

Orientation

understanding your location in space; a position or path in relation to an environmental cue

Navigation

Moving towards a specific destination using information

Pheromone

chemical emitted into the environment that elicits specific behavioral responses form other members of the species

Migration

long-range, seasonal movement of animals

Direct fitness

Fitness gained through the direct production of offspring. 

Indirect fitness

Fitness gained through actions that enhance the production of non-offspring kin. 

Inclusive fitness

The combination of direct and indirect fitness. 

Kin selection

natural selection favors behaviors that benefit genetically related individuals by increasing indirect fitness benefits to altruist 

Eusociality

A form of social organization where only one or a few individuals are reproductively active and produce offspring, where most individuals in the group do not reproduce and instead help raise the young of reproductive individuals.

Social Behaviors

interactions between conspecifics

Altruism

behavior that reduces direct fitness of the actor but is beneficial to other individuals in the group

Hamilton’s Rule

rB > C

r in Hamilton’s Rule

relatedness: proportion of shared genes

B in Hamilton’s Rule

benefit to recipient: number of offspring produced

C in Hamilton’s Rule

cost to altruist

Biological Determinism

individual’s behaviors are fixed by their genetic makeup (almost never true)

Epigenetics

modifications to DNA that regulate whether a gene is expressed or not

Methylation

natural process of adding methyl groups to parts of DNA which suppress the gene

Histone Acetylation

promotes gene expression

Communication

transfer of information between individuals that affects the behavior of the receiver

Chemical Communication

a chemical signal that triggers a response in the recipient; tons of info can be communicated

Alarm Pheromones

triggers a fight or flight response in members of the same species

Trail Following Pheromone

can guide other colony members to a food source

Sex Pheromone

in insects, females can communicate location and availability for mating

Visual Signals

rapid delivery of information over a long distance

Acoustic Signals

sound signals; can be used at night or in dark environments

Mechanosensory Signals

communication by touch or vibrations