1. An example of a pioneer species is A. wheat
B. ferns
C. bees
D. buffalo
2.Primary succession in an area of Alberta today occurs because of the effects of
A. glaciation
B. clearcut logging
C. mountain formation
D. the controlled burn of a forest
3. Primary succession can be observed through aquatic succession by noting
A. changes in the numbers and types of organisms
B. the appearance of a particular organism
C. the disappearance of a particular organism
D. that no changes occurred
4. Match each description with the appropriate term listed. Place your answer in the blank space given
.i. humus
ii. primary succession
iii. pioneer species
iv. climax community
a. This stable community results from the process of succession.
b. These simple and hardy plants first colonize barren ground or rock.
c. This organic component of soil is produced from decomposed organisms.
d. This is the process of changing an environment from bare rock and a few species to a complex community with many species.

1. B (ferns)

2. A (glaciation)

3. B (the appearance of a particular organism)

4

i. C

ii. D

iii. B

iv. A

Explanation:

1. Pioneer species in succession refers to species that first colonize a barren land or rock. They include species that can adapt to the condition of the land and subsequently break it down for other organisms to grow. Pioneer species in primary succession include ferns, lichens etc.

2. Primary succession occurs as a result of effects or negative impacts on an area. Specifically, primary succession in an area of Alberta today occurs because of the effects of GLACIATION, which is the covering of land surface with ice.

3. The appearance of a particular organism such as pioneer species in an aquatic succession can be an indicator of primary succession.

4. * Humus is an organic component of soil that is produced from decomposed organisms.

* Primary succession is the process of changing an environment from bare rock and a few species to a complex community with many species.

* Pioneer species are simple and hardy plants that first colonize a barren ground or rock.

* Climax community is a stable community that results from the process of succession.

regulation of gene expression. gene expression can be regulated by various cellular processes with the aim to control the amount and nature of the expressed genes. these regulatory proteins bind to dna and send signals that indirectly control the rate of gene expression

explanation:

synovial joints are characterized by the presence of a joint cavity. the walls of this space are formed by the articular capsule, a fibrous connective tissue structure that is attached to each bone just outside the area of the bone’s articulating surface. the bones of the joint articulate with each other within the joint cavity.

friction between the bones at a synovial joint is prevented by the presence of the articular cartilage, a thin layer of hyaline cartilage that covers the entire articulating surface of each bone. however, unlike at a cartilaginous joint, the articular cartilages of each bone are not continuous with each other. instead, the articular cartilage acts like a teflon® coating over the bone surface, allowing the articulating bones to move smoothly against each other without damaging the underlying bone tissue. lining the inner surface of the articular capsule is a thin synovial membrane. the cells of this membrane secrete synovial fluid (synovia = “a thick fluid”), a thick, slimy fluid that provides lubrication to further reduce friction between the bones of the joint. this fluid also provides nourishment to the articular cartilage, which does not contain blood vessels. the ability of the bones to move smoothly against each other within the joint cavity, and the freedom of joint movement this provides, means that each synovial joint is functionally classified as a diarthrosis.

outside of their articulating surfaces, the bones are connected together by ligaments, which are strong bands of fibrous connective tissue. these strengthen and support the joint by anchoring the bones together and preventing their separation. ligaments allow for normal movements at a joint, but limit the range of these motions, thus preventing excessive or abnormal joint movements. ligaments are classified based on their relationship to the fibrous articular capsule. an extrinsic ligament is located outside of the articular capsule, an intrinsic ligament is fused to or incorporated into the wall of the articular capsule, and an intracapsular ligament is located inside of the articular capsule.

at many synovial joints, additional support is provided by the muscles and their tendons that act across the joint. a tendon is the dense connective tissue structure that attaches a muscle to bone. as forces acting on a joint increase, the body will automatically increase the overall strength of contraction of the muscles crossing that joint, thus allowing the muscle and its tendon to serve as a “dynamic ligament” to resist forces and support the joint. this type of indirect support by muscles is very important at the shoulder joint, for example, where the ligaments are relatively weak.

additional structures associated with synovial joints

a few synovial joints of the body have a fibrocartilage structure located between the articulating bones. this is called an articular disc, which is generally small and oval-shaped, or a meniscus, which is larger and c-shaped. these structures can serve several functions, depending on the specific joint. in some places, an articular disc may act to strongly unite the bones of the joint to each other. examples of this include the articular discs found at the sternoclavicular joint or between the distal ends of the radius and ulna bones. at other synovial joints, the disc can provide shock absorption and cushioning between the bones, which is the function of each meniscus within the knee joint. finally, an articular disc can serve to smooth the movements between the articulating bones, as seen at the temporomandibular joint. some synovial joints also have a fat pad, which can serve as a cushion between the bones.