SBI4U – Grade 12 AP Biology – Ecology Test


Thanks, Bairavi Sripalan!



Population Size = (Birth Rate + Immigration) – (Death Rate + Emigration) ÷ (n) 100

Reproductive Strategies

 Sea turtles large offspring , low survival rate

 Mammals small offspring, parental involvement high survival rate


**density dependent

Intraspecific Factors (within a species)

– diseases**, human intervention, pests* and competition** for: food, shelter, mates

Interspecific Factors

– competition**, human intervention & predators**



 a species has a number of variables that affect it and it affects

 a 3D space that includes all variables the species requires and affect


Herbivore – animals that eat vegetation

Carnivore – animals that eat other animals

Omnivore – animals that eat both vegetation and other animals

Symbiotic relationships – two species living together

 Mutualism (both benefit)

 Paratism ( 1 benefits as the other loses)

 Commensalism (one benefits as the other is unaffected)


Food Chains, Food Webs and Food Pyramids

Biotic Factors

Factors that affect the distribution of organisms include

 Interactions with other species

 Competition

 Predators



Movement of individuals away from centers of high population density or from their area of origin

Contributes to global distribution of organisms

Species transplants

Organisms that are intentionally or accidentally relocated from their original distribution

Disrupt the communities or ecosystems to which they have been introduced

 Endemic species —> local

 Transplanted species —> from another area

 Invasive —> if it spreads without predator


Behavior and Habitat Selection

Some organisms do not occupy all of their potential range

Species distribution may be limited by habitat selection behavior



Oligotrophic LakesNutrient-poor and generally oxygen-rich

Eutrophic Lakes Nutrient-rich and often depleted of oxygen if ice covered in winter Rooted and floating aquatic plants live in the shallow and well-lighted littoral zone


 A habitat that is covered by water most of the time and that supports plants adapted to water-saturated soil

 Can develop in shallow basins, along flooded river banks, or on the coasts of large lake and seas


Streams and Rivers

 Physical characteristic is current



 A transition area between river and sea

 Nutrient rich and highly productive


Intertidal Zones

 Periodically submerged and exposed by the tides

 Challenged by variations in temperature and salinity and by mechanical forces of wave action


Oceanic Pelagic Zone

 A vast kingdom of open blue water, constantly mixed by wind-driven oceanic currents

 Covers approximately 70% of Earth’s Surface


Coral Reefs

 Formed from the calcium carbonate skeletons of corals

 Phylum cnidaria

 Require a solid substrate for attachment

 Water can act like a temperature regulator in coral ecosystems


Marine Benthic Zone

 Consists of the seafloor below the surface waters of the coastal, or neritic, zone and the offshore pelagic zone

 Organisms in the abyssal, zone are adapted to continuous cold and extremely high water pressure


Terrestrial Ecosystems

 The ecotone is the area of integration between terrestrial biomes

 Canopy – the top layer of a forest, and it can have many layers


Tropical Forests

Tropical rainforests

 Rainfall is relatively constant


Tropical dry forests

 Precipitation is highly seasonal

 Vertically layered and competition for light is intense



 Precipitation- low and high variable

 May be hot or cold

 Desert plants

 Adapted for heat and drought tolerance, water storage, and reduced leaf surface area



 Precipitation and temperature are seasonal



 Climate

 Highly seasonally

 Cool and rainy winters and hot dry summers

 Dominated by shrubs, small trees, grasses, and herbs

 Adapted to fire and drought

 Animals that look for food have to search in distinctive way


Temperate Grassland

 Found on many continents

 Climate

 Winters are cold and dry

 Summers are wet and hot

 Dominated plants, grasses and shrubs

 Adapted to droughts and fire


Northern Coniferous Forest

 Extends across North America and Eurasia

 Largest terrestrial biome on Earth

 Climate

 Winters are cold and long

 Summers may be hot

 Pointed shape of conifers prevents too much snow from accumulating and breaking their branches


Temperate Broadleaf Forest

 Climate

 Winters are cool

 Summers are hot and humid

 Major precipitation falls year round as rain and snow

 Vertical layers dominated by deciduous trees in the Northern Hemisphere and ever green eucalyptus in Australia

 Mammals hibernate in the winter, Northern Hemisphere



 Expansive areas of the Arctic

 Alpine tundra exists on high mountaintops at all latitudes

 Low levels of oxygen

 Climate

 Winters are long and cold

 Summers are relatively cool

 Precipitation varies

Permafrost – permanently frozen layer of soil, prevents water infiltration

 Vegetation is herbaceous and supports birds, grazers and their predators