Brief-Constructed Response
Biotic and Abiotic Factors
Teacher Guide
Biotic and Abiotic Factors
Objectives assessed: The student will be able to demonstrate understanding that:
• An environment is composed of interconnected biotic and abiotic factors.
• Both organisms and populations depend on biotic and abiotic factors.
• Organisms of the same species compete for biotic and abiotic factors.
• Different populations compete for biotic and abiotic factors.
Students will need about 15–20 minutes to complete this brief constructed response.
In a tropical rain forest, tall trees crowd together, blocking the path of sunlight to the wet forest floor.
Among the plants adapted to these conditions are climbers, such as vines that grow up along the
tree trunks. Other plants, such as orchids, grow attached to tree branches and are not rooted in the
ground. Even a small area of forest provides various habitats for vast numbers of animal and plant
species. Many insects and birds are plant pollinators. Fruit-eating animals, such as birds and bats,
spread seeds. Insects, fungi, and bacteria break down plant and animal matter, releasing nutrients
into the soil. Predators, such as jaguars and snakes, feed on smaller animals.
Directions:
Describe how organisms and populations in the tropical rain forest both depend on and compete for
biotic and abiotic factors. In your answer, identify which factors are biotic and which are abiotic.
Sample correct response:
Abiotic factors in a tropical rain forest include water, a warm climate, sunlight, and soil nutrients. All
organisms and populations in the tropical rain forest depend on water and warm temperatures.
Plants depend directly on sunlight and soil nutrients.
Biotic factors in a tropical rain forest include all of the organisms that live there. Vines and orchids
depend on the trees as a way to reach the light. Some plants depend on insects or birds for
pollination, or birds or bats to spread their seeds. Indirectly the plants depend on organisms that
release nutrients into the soil. Animals depend on the other animals or plants that they eat.
Individual organisms of all types compete for space in a tropical rain forest. Space is an abiotic
factor that is influenced by the plant life, a biotic factor. Plants also compete for sunlight and
nutrients. Animals may compete against one another for food and mates.
Populations also compete for space in a tropical rain forest. Plant populations compete for sunlight,
nutrients, and possibly pollinators. Animal populations may compete for prey animals or fruit.
Brief Constructed Response: Biotic and Abiotic Factors
© Discovery Communications, LLC
Page 1 of 2
Brief-Constructed Response
Biotic and Abiotic Factors
Teacher Guide
Response scoring tool:
Score Content
3
Student response has at least three of the following:
• Demonstrates an understanding of the interdependence
among different biotic and abiotic factors.
• Demonstrates an understanding of how organisms
compete for biotic and abiotic factors.
• Demonstrates an understanding of how populations
compete for biotic and abiotic factors.
2
Student response has at least two of the following:
• Demonstrates an understanding of the interdependence
among different biotic and abiotic factors.
• Demonstrates an understanding of how organisms
compete for biotic and abiotic factors.
• Demonstrates an understanding of how populations
compete for biotic and abiotic factors.
1
Student response has at least one of the following:
• Demonstrates an understanding of the interdependence
among different biotic and abiotic factors.
• Demonstrates an understanding of how organisms
compete for biotic and abiotic factors.
• Demonstrates an understanding of how populations
compete for biotic and abiotic factors.
0
No response or response not appropriate to the question.
Brief Constructed Response: Biotic and Abiotic Factors
© Discovery Communications, LLC
Page 2 of 2