Crossword

1 M   2 D  I  S  T  U  R  B  A  N  C  E     3 E    
 A    I                     4 C    C    
 S    S         5 R  A  I  N  S  H  A  D  O  W  
 S    T     6 P                N    L    
 E    R     7 R  A  N  D  O  M      O    O    
 X    I      O           8 D    P    G    
 T   9 B  I  O  D  I  V  E  R  S  I  T  Y    Y    
 I    U      U            S            
 N    T      C   10 B  I  O  S  P  H  E 11 R  E    
12 C  L  I  M  A  T  E          E      A     13 R
 T    O      I   14 H        R   15 B  I  O  M  E
 I    N      V    A   16 C    S      N      G
 O          I    B    L    A      F      U
 N          T    I    U    L      O      L
  17 E  C  O  S  Y  S  T  E  M          R      A
               A    P          E      R
        18 W  E  A  T  H  E  R        S      
                   D          T      

Across:

2An event, such as a fire or windstorm, that kills or damages some organisms in a community, thereby creating an opportunity for other organisms to become established.
5(2 words, no space) An area on the side of a mountain facing away from moist prevailing winds where little rain or snow falls.
7A distribution pattern in which organisms tend to be positioned in an unpredictable manner throughout the environment.
9The variety of organisms on Earth or in a particular location, ranging from the genetic variation and behavioral diversity of individual organisms or species through the diversity of ecosystems.
10All living organisms on Earth, together with the environments in which they live.
12The prevailing weather conditions experienced in an area over relatively long periods of time (30 years or more).
15A major terrestrial or aquatic life zone, defined either by its vegetation (terrestrial biomes) or by the physical characteristics of the environment (aquatic biomes).
17A community of organisms, together with the physical environment in which the organisms live.
18Temperature, precipitation, wind speed, humidity, cloud cover, and other physical conditions of the lower atmosphere at a specific place over a short period of time.

Down:

1(two words, no space) A period during which large numbers of species become extinct throughout most of Earth.
2The geographic area or range over which a species is found.
3The scientific study of interactions between organisms and their environment.
4The habitat in the branches of forest trees.
6The mass of plant matter that a plot can produce from the available nutrients and sunlight.
8An act in which individuals travel relatively long distances away from other members of their species.
11A forest that receives high rainfall.
13A distribution pattern in which organisms tend to be positioned in an even or uniform manner throughout the environment.
14A characteristic place or type of environment in which an organism lives.
16A distribution pattern in which organisms tend to be clustered together throughout the environment.