Life History
This theory predicts how an organism allocates energy to growth, reproduction, and survival across its life.
Life History
The basic unit of ecological study; individual survival and behavior drive population changes. Name this unit.
Natural Selection
Which plant feature acts as a waxy barrier to reduce water loss?
Cuticle
In Life History Theory, a "trade-off" means energy invested in one function cannot be used for another. Give a simple example.
Example: Energy put into many seeds reduces the energy available for each seed (size/quality)
A life history trait commonly found in species with short lifespans: reproduce ______ and produce ______ offspring.
Quickly, Many
Give one clear example of how a single organism can directly affect an ecosystem process
Beavers, Wolves, Elephants
Name a leaf shape or structure that helps plants capture more light in low-light environments.
Large broad leaf
Limited resources force organisms to make trade-offs. Name two life processes that commonly compete for those resources.
Growth vs reproduction; reproduction vs survival (maintenance).
Name two contrasting life history strategies using r-selected and K-selected terminology (one short-lived, one long-lived).
Elephants vs. Bacteria
Explain how individual behavior can change population size in one complete sentence.
Answers Vary
Describe one root adaptation that helps a plant access water or nutrients better than its neighbors.
Deep taproots access groundwater; widespread shallow roots capture surface water quickly.
Explain how producing many offspring with low parental care is adaptive in unpredictable environments. Use two supporting points.
Producing many offspring increases chance at least some survive when environment is unpredictable; low investment per offspring reduces parental cost and allows more reproductive events.
Give an ecological reason why an organism might delay reproduction until later in life.
Lack of food/ resources
A plant closes its stomata during drought. Classify this as (a) evolution, (b) individual physiological response, or (c) population-level change — then justify your choice
(b) individual physiological response
The behavior is occurring with an individual organism, and it is happening in response to stimuli which may change several times daily
A plant in salty soil often accumulates salts inside cells or excretes them. Explain how this adaptation improves survival in flooded or saline environments.
Salt excretion or compartmentalization prevents cellular damage from osmotic stress; it helps maintain water uptake and metabolic function in saline/flooded conditions.
Choose one plant adaptation (e.g., thick cuticle) and explain how it represents a trade-off between survival and growth or reproduction.
thick cuticle conserves water (survival) but requires energy and materials to build, potentially reducing resources for growth or seed production.
Describe a real-world example (species) that shows a trade-off between reproduction number and parental care; explain the trade-off.
answers vary
Describe how studying individuals helps scientists predict carrying capacity for a population (include one factor that individuals reveal which informs carrying capacity).
A review of an animal's ecological role helps us to understand the space and nutritional needs of the species
Predict and explain one anatomical or physiological adaptation a plant might evolve if its habitat experiences frequent flooding.
Adaptation: aerenchyma (air-filled tissues) or adventitious roots to tolerate low-oxygen soils and prevent root rot.
Using Life History Theory, analyze how climate change (e.g., more frequent droughts) might shift the life history strategy of a small mammal species over several generations. Include at least two mechanisms (selection pressures, trade-offs, reproductive timing).
Climate change could favor earlier reproduction and smaller body size (selection for earlier maturity), increased reproductive rate but lower offspring size/quality; mechanisms: higher juvenile mortality selecting for earlier reproduction, limited resources forcing trade-off toward more but smaller offspring.