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EXAM 1

  1. Short Answer/Define- choose 10 (4 pts each=40 pts)

Adaptation-The process whereby living organisms change over time to fit into their surroundings.
Birthrate-The annual overall live births out of 1,000 births in a particular population.
Community-A group of people, small or large, who practice a common way of life such as religion or identity, among others.
Crop Rotation-the practice of farming more than one type of crop in the same land with the intention of making maximum utilization of the soil nutrients, preventing soil erosion, and controlling weeds.
Ecology-The study of how organisms interact with each other and their environment.
Ecosystem– A network of living things, their surroundings, and their interactions in a unit area.
Emigration-Moving from one’s residential country to a nation with the intention to settle there permanently.
Foodweb-A visual representation of the various food chains and preys and predators in an ecosystem.
Predation-The act of preying or attacking and eating other creatures
Primary Consumer-An animal that feeds on plants in a food chain, also referred to as a herbivore.

  1. List and describe our six terrestrial biomes. (15 pts)

Desert-An area that receives a precipitation of less than 25 cm annually, exhibits extremely high temperatures and powerful sunlight, and cold nights. Plants and animals in this biome are adapted to dry weather.
Grasslands-land distinguished by extensive growth of grass and few trees mostly in arid areas. Yearly amount of rain is normally between 25.4 cm-88.9cm
Tropical rain forests-areas mostly located in the equatorial regions with temperature ranges of 20oC to 34oC, consistent sunlight, and between 125cm-660 cm of rainfall annually. Trees are often crowded since this biome is highly productive.
Temperate forests-Biomes found mainly in mid-latitude regions characterized by 22oF to 86oF temperatures and 75 cm to 150 cm annually. The common plant in these forests are the deciduous trees.
Tundra-A biome that experiences –34°C and 3°C–12°C average temperatures during the winter and summer seasons respectively. The annual amount of rainfall is often 15-25 cm, and mostly found in the arctic regions.
Taiga/boreal forest-Distinguished by approximately 55° temperatures and between 40 cm to 100 cm precipitation.

  1. Draw/label/explain the biomass pyramid. (10 pts)

The biomass pyramid is a representation of the quantity of biomass in each trophic level in a given area of an ecological system. Energy capacity is the highest at the bottom and decreases as one moves up the ladder (Bar-On, Yinon, Rob, and Ron 6507). It consists of primary producers, primary and secondary consumers, and tertiary consumers which occupy the top levels of the pyramid.

  1. Explain why there are fewer lions than mice in an African system. Draw graphs if needed.  Think hard before you answer this question! (20 pts)

In an African system, there are fewer lions than mice. The rationale behind this is that mice have plenty of seeds, grains, and fruits that grow in those areas as well as primary consumers such as insects that feed on plants. Besides, they have a shorter gestation period which increases their abundance. On the other hand, lions only eat mice only as supplementary food but their main source of food includes animals such as antelopes, zebras, and buffaloes, among others. Since lions cannot rely on mice, this explains why they are few.

  1. “Shorter” Essays (15 pts each = 30 pts)
    1. Who is Gause? Georgy Gause was a Russian-based biologist.

What did he do? He came up with the competitive exclusion principle, also known as Gause’s law which is vital in ecological science. The theory implies that two organisms that compete for limited food cannot coexist.

  1. Why are falling birth rates NOT necessarily a reliable indicator of future population growth trends?

Birth rate is not reliable tor predicting future population trends since it only focuses only on the current live births. Besides, other indicators such as fertility rates are more suitable for forecasting how the population will be in the coming years.

  1. “Longer” Essays.  Pick 3 (25 pts each = 75 pts total)
    1. Explain why climatic factors are so important in the distribution/abundance of plant/animal species. Refer to notes and text.

Changes in climate are vital as they can determine whether animal or plant species will survive and hence, reproduce. For instance, dry weather can hinder plant growth, making it difficult for primary producers to survive and most likely, die. As such, there can be a reduced number of animals that feed on plants if it is limited as a result of whether alterations.

  • Compare/contrast exploitative competition and interference competition. Use examples. Refer to textbook and other sources.

Exploitative competition is seen when animals compete for a resource they all need, which is limited. For instance, when species occupy an entire space, making it difficult for other organisms to live there. On the other hand, interference competition is assumed when species obstruct the availability of something through aggression or fighting. For example, when two male deers fight for a female during mating. These two types of competition are similar in the sense that both exhibit the need to survive.

  1. How can a predator influence a prey’s population? Use examples from the text and from lab.

Predators feed on preys, reducing their population. For instance, lions eat gazelles. As such, the number of gazelles reduces with time.

  1. Using your Field Guide, describe the Natural History of a rock dove or pigeon. (10 pts)

Rock doves, also known as pigeons have had a close relationship with humans. For centuries, man has used them as a symbols, food, sacrifices, and messengers. This is because they have high adaptability to domestic lime and easily tamable.
 
Works Cited
Bar-On, Yinon M., Rob Phillips, and Ron Milo. “The biomass distribution on Earth.” Proceedings of the National Academy of Sciences 115.25 (2018): 6506-6511.