Chordata and Ecology

Chordata Key Traits

Dorsal hollow nerve cord, notochord, pharyngeal slits, and post-anal tail at some life stage.

Tunicate

Sessile marine filter feeder that retains chordate features (esp. notochord, nerve cord) in larval stage.

Cartilaginous Fish

Sharks, rays; differ from bony fish by having a cartilaginous skeleton and lack of swim bladder.

Bony Fish Groups

Ray-finned and lobe-finned; lobe-fins are pivotal for tetrapod evolution.

Amphibian Land Adaptations

Limbs with digits, lungs, cutaneous respiration, and reproduction tied to water (eggs without shell).

Reptile Land Adaptations

Amniotic egg, keratinized scales, lungs with expandable rib cage, internal fertilization.

Bird (Aves) Adaptations

Feathers, hollow bones, endothermy, four-chambered heart, and high metabolic rate for flight.

Three groups of mammals

Monotremes, marsupials, placentals.

Monotremes

are egg-laying mammals, such as the platypus and echidna, that nurse their young with milk.

Marsupials

are mammals that give birth to underdeveloped young, which typically continue to develop in a pouch, such as kangaroos and koalas.

Placentals

are mammals that nourish their young in the womb through a placenta, allowing for more advanced development before birth, including species like humans and elephants.

How does development challenges differ between marsupials and placentals?

Marsupials are mammals that give birth to underdeveloped young, which typically continue to develop in a pouch, while placentals are mammals that nourish their young in the womb through a placenta, allowing for more advanced development before birth.

Adaptations of placentals (eutherians)

longer gestation periods, and more developed offspring at birth compared to marsupials, fur for endothermy, and mammary glandsfor milk production.

Ecology

Scientific study of interactions between organisms and their environment.

Community

Assemblage of populations living in a common area.

Population

Group of individuals of the same species in a defined area.

Organismal Ecology

Study of how an individual’s structure, physiology, and behavior meet environmental challenges.

Population Ecology

Examination of factors affecting population size and change.

Community Ecology

Study of interactions among species in a community.

Ecosystem Ecology

Analysis of energy flow and nutrient cycling among organisms and abiotic factors.

Landscape Ecology

Study of exchanges of energy and materials across multiple ecosystems.

Global Ecology

Examination of planet-wide interactions influencing life and climate.

Climate

Long-term prevailing weather conditions of an area.

Macroclimate

Large-scale climate patterns at regional or global levels.

Microclimate

Localized, fine-scale climate conditions, often differing from the surrounding area.

Thermocline

Stratified water layer where temperature changes rapidly with depth.

Turnover

Seasonal mixing of lake waters that redistributes oxygen and nutrients.

Rain Shadow Effect

Dry region on leeward side of mountains due to moisture loss on windward slopes.

Big Six Elements

Carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur—essential for life.

Carbon Cycle

Global movement of carbon through photosynthesis, respiration, combustion, and decomposition.

Greenhouse Effect

Warming caused by atmospheric gases trapping infrared radiation.

Nitrogen Fixation

Conversion of atmospheric N₂ to ammonia by bacteria, making nitrogen bioavailable.

Eutrophication

Nutrient over-enrichment leading to algal blooms and oxygen depletion in water bodies.

Water Cycle

Continuous movement of water through evaporation, condensation, precipitation, and runoff.

Aquatic Biome

Large water-based ecosystem categorized as marine or freshwater by salinity.

Photic Zone

Upper aquatic layer that receives sufficient light for photosynthesis.

Benthic Zone

Aquatic bottom substrate, including sediment and organisms living on or in it.

Primary Succession

Community development on bare substrate lacking soil, such as after volcanic activity.

Secondary Succession

Recovery sequence in areas where soil remains after disturbance (e.g., fire).

Intermediate Disturbance Hypothesis

Concept that species diversity peaks at moderate levels of disturbance.

Predation

Interaction where one organism (predator) kills and eats another (prey).

Aposematic Coloration

Bright warning coloration signaling toxicity or danger to predators.

Batesian Mimicry

Harmless species mimics warning signals of a harmful species to deter predators.

Competition

Interaction where organisms vie for the same limited resource.

Competitive Exclusion

Principle that two species sharing the same niche cannot coexist indefinitely.

Resource Partitioning

Differentiation of niches enabling similar species to coexist.

Parasitism

Symbiosis where one organism benefits at the expense of the host (+/−).

Mutualism

Symbiotic relationship where both species benefit (+/+).

Commensalism

Symbiosis where one species benefits and the other is unaffected (+/0).

Ecological Niche

Sum of a species’ use of biotic and abiotic resources in its environment.

Fundamental Niche

Entire set of conditions a species can theoretically occupy without competition.

Realized Niche

Actual conditions a species occupies in the presence of competitors.

Species Richness

Number of different species present in a community.

Relative Abundance

Proportion each species represents of total individuals in the community.

Trophic Structure

Pattern of feeding relationships and energy flow in an ecosystem.

10% Rule

Approximate proportion of energy transferred from one trophic level to the next.

Keystone Species

Species that exerts a disproportionate influence on community structure relative to its abundance.

Species Transplant

Relocation of a species outside its native range, often leading to invasive impacts.