236 ❯ STEP 4. Review the Knowledge You Need to Score High
- Type II:constant death rate across the age spectrum—lizards, hydra, small mammals.
- Type III:steep downward death rate for young individuals that flattens out at certain
age—fish, oysters.
Forms of Species Interaction- Parasitism:one organism benefits at another’s expense (tapeworms and humans).
- Commensalism:one organism benefits while the other is unaffected (cattle egrets and
cattle). - Mutualism:both organisms reap benefits from the interaction (acacia trees and ants,
lichen). - Competition:both species are harmed by the interaction (intraspecificvs.interspecific).
- Predation:one species, the predator, hunts the other, the prey.
Defense Mechanisms- Cryptic coloration:coloring scheme that allows organism to blend into colors of
environment. - Deceptive markings:patterns that cause an animal to appear larger or more dangerous
than it really is. - Aposematic coloration:warning coloration adopted by animals that possess a chemical
defense mechanism. - Batesian mimicry:animal that is harmless copies the appearance of an animal that is
dangerous. - Müllerian mimicry:two aposemetrically colored species have a similar coloration
pattern.
Primary succession:occurs in area devoid of life that contains no soil; pioneer speciescome
in, add nutrients, and are replaced by future species, which attract animals to the area, thus
adding more nutrients; constant changing of guards until the climax community is
reached and a steady-state equilibrium is achieved.
Secondary succession:occurs in area that once had stable life but was disturbed by major
force (fire).Biomes: The Special Facts
We recommend that you read the biome material in the chapter for more detail.- Desert:driest land biome.
- Taiga:lengthy cold, wet winters; lots of conifers.
- Temperate grasslands:most fertile soil of all.
- Tundra:permafrost, cold winters, short shrubs.
- Savanna:grasslands, home to herbivores.
- Deciduous forest:cold winters/warm summers.
- Tropical forest:greatest diversity of species.
- Water biomes:freshwater and marine biomes of earth.
Trophic levels:hierarchy of energy levels on a planet; energy level decreases from bottom
to top (Figure 18.7); primary producers (bottom) →primary consumers (herbivores) →
secondaryconsumers→tertiary consumers →decomposers.