APES TEST 2

  1. Compare primary and secondary succession.  Include an example of each.

    1. Primary- the process of recreating a climax community after a disturbance that removes the all vegetation and soil (ex: glacial retreat, lava flow, development of new roads)

  1. Secondary- the process of recreating a climax community after a disturbance that removes all the vegetation but leaves the soil intact (ex: forest fire, hurricane, agriculture)



  1. Describe the characteristics of the following species:

  1. Pioneer species- first to colonize an area after a disturbance, usually tolerant of poor soil fertility, and long periods of time indirect sunlight

    1. Terrestrial - lichen/moss (initiate soil formation by breakdown of rock)

    2. Aquatic - algae

  2. Niche generalists- species adapted to eat a variety of food and/orlive in a variety of habitats.  Less susceptible to extinction after a disturbance

  3. Niche specialists- species adapted to eat only one particular food and/or live in one particular habitat.  More susceptible to extinction after a disturbance


  1. Identify 2 examples of pioneer species and late successional species after primary and secondary succession.

    1. Pioneer species- lichens and mosses

    2. Late successional species- Beech, Maple, Hickory trees


  1. Define species richness and species evenness.

    1. Richness- refers to the number of different species living in an ecosystem

    2. Evenness- refers to how similar the distribution of individuals is among various species in an ecosystem


  1. Explain the theory of island biogeography

    1.  is the study of the ecological relationships and distribution of organisms on islands, and of these organisms community structures


  1. Compare the biodiversity of small islands vs. large islands, and nearby islands vs. distant islands 

    1. Large islands will have more species diversity than smaller islands because they are more likely to have more habitat diversity, and are easier for colonizing species to find.  Islands nearer to a source of species will have more species diversity than islands that are farther away because they are easier to get to and locate.  As new species adapt to island ecosystems, new species will often evolve (speciation) because of the geographic and reproductive isolation from other individuals outside of the island


  1. Describe conditions that could lead a species to go extinct

    1. Lack of a favorable environment close enough to which a species can move

    2. New environment may already be occupied by other species against which the moving populations cannot successfully compete

    3. Environmental change may occur so rapidly that the species does not have time to evolve new adaptations


  1. Identify 2 terrestrial biomes with high biodiversity and 2 terrestrial biomes with low biodiversity

    1. High- wetlands and tropical rainforests

    2. Low- desert and tundra


  1. Describe selective pressure:

    1. The environmental condition that kills individuals without the adaptation


  1.  Describe the bottleneck effect

    1. Bottleneck effect- a reduction in the genetic diversity of a population caused by a reduction in its size


  1. Describe each of the ecosystem services

    1. Provisioning- provides goods that humans can use directly

      1. Includes food, drinking water, timber, wood fuel, natural gas, oils, plants that can be made into cloths and other material, and medicinal benefits

    2. Regulating- natural ecosystems help regulate environmental conditions

      1. Ex: Forests removing CO2 from the atmosphere

    3. Cultural- People willing to pay to see the aesthetic beauty of an ecosystem.  There can also be intellectual gain in studying these ecosystems

    4. Supporting- includes pollination of food crops, natural pest control services, and filtering harmful chemicals and pathogens from water


  1. Describe the effects of low genetic diversity on a population

    1. Can cause genetic abnormalities to be passed on where in populations with high genetic diversity can usually breed those mutations out

      1. Founders effect



"Range of tolerance" refers to the range of environmental conditions, like temperature, pH, or salinity, within which an organism can survive and thrive, with the upper limit being the maximum tolerable level and the lower limit being the minimum tolerable level; essentially, it's the "sweet spot" where an organism performs best without experiencing stress or harm from environmental factors.



Selective pressure is an evolutionary force that influences the reproduction and survival of a population, and is a driver of natural selection. It occurs when certain phenotypes, or observable traits, are more favorable in a given environment. This can lead to adaptations, which are body plans or lifestyles that give an advantage in a specific environment.



Keystone species: an organism that plays a vital role in the survival of other species in its ecosystem. Keystone species are often a key part of the local food web, and their absence can lead to the collapse of an ecosystem. Here are some examples of keystone species: