Exam Preparation B2 C1 Lesson 12: Insects and Plants

B2/C1 Exam Preparation Course Lesson 12: Insects and Plants

Ant Plants: Cecropia Azteca Symbiosis

The Cecropia tree is one of the most abundant species found in clearings and forest gaps in tropical rain forests. In these regions of high competition amongst plants and animal species, for survival, much of this tree’s success has been attributed to a special mutualism.
Cecropia trees provide a safe, climate controlled shelter for housing a fierce ant genus, known as Azteca. In addition, these trees supply nutrients to their ant colonies through tiny grows called “mullerian food bodies” which are harvested by the ants. These serve no reproductive purpose for the plant, but are produced exclusively for the nourishment of the Azteca colonies. In return for food and shelter, the ants act as the plants nervous and defense systems. Invasive, destructive elements such as herbivores and leaf cutter ants are quickly swarmed and immobilised, and removed from the tree. The ants even help the Cecropia tree ward off competitive, encroaching vines. Also, tidy, specialised hooks coating the surface of the trunk work together with spurs on the ants legs to increase the ants grip strength and overall defensive capabilities.
Researchers at Arizona State University and Georgia Tech are working together on new digital tools for understanding biological interactions and mechanisms, such as those leading to the success of this Azteca/Cecropia ant/plant hybrid.

Information Processing in Social Insect Networks
James S. Waters /  Jennifer H. Fewell

Capturing the essence of biological networks is among the most important challenges facing modern science. Gene regulation, motor control, developmental specialization, and metabolic allometry all emerge as the result of integrated networks. These networks operate at different biological levels but all distribute and transform localized information into larger scale processes. However, not all biological networks develop or evolve around higher order function. Social networks, the broad class of networks characterizing human and animal social groups, are typically thought to exhibit global-structure consistent with the predictions of generative network models such as preferential attachment. In these systems, interactions benefit and reinforce an individual’s own role within the network, but at a potential cost to higher-level properties such as efficiency or resilience.
Although generally clustered into one category, social networks can describe many different types of complex systems from aggregations to cohesive social units. Network analyses show global similarities across social systems; they are generally decentralized and scale-free, with network structure emerging from local interactions in the absence of an external controller. However, the function of interactions within social groups should vary with the evolutionary and ecological contexts in which the group evolves. The social interactions within, for example, a pod of dolphins or extended family groups of ground squirrels, should serve very different functions than the communication networks among workers within a eusocial insect colony.
Social insect colonies are the hallmark of integrated social units, exhibiting some of the most awe-inspiring examples of complexity in the biological world. Nest architecture that promotes environmental stability, division of labor that scales with colony size, and collective decision making all take place in the absence of hierarchical control. Social insect communication systems, which include such diverse modalities as direct individual contact, trophallaxis, and broadcast pheromonal signaling, show they are highly regulated units with coordinated individual behaviors that generate emergent effects which are beneficial to the group as a whole. If network structure reflects biological function, then the structure of a social insect colony should vary distinctly from that of social networks generated from associations based on individual success.
We investigate network motif profiles of seed harvester ant colony interaction networks to determine whether their antennation patterns are predominantly random, regulatory, or social in nature. Since the purpose of antennation by ants is to obtain information, the structure of their communication networks is critical to how colonies function. Motif analysis determines the predominant local interaction patterns (3-node directed subgraph motifs) making up a network and has the potential to identify fundamental interaction signatures within networks of different size or context that may correspond to differences in functionality. Previous work by Milo and his colleagues has shown that biological regulatory networks have predominant interaction patterns that move information directionally, while social networks develop bidirectionally-connected cliques as individuals mutually strengthen associations with their neighbors. We ask whether these different types of subgraph representation allow us to differentiate between networks selected for at the individual-level and networks that emerge as a result of group-level selection.
(SOURCE: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0040337)

WRITING SKILLS

You can either:
* Complete 2 writing assignments. You have 40 minutes if you wish to complete one now. The 2nd assignment you can complete at home.
* You can also watch our Grammar VIDEO tutorials during the next 40 minutes if you prefer to complete the Writing at home.

For IELTS (Academic format), please select the ESSAY topic (250 words: in 40 minutes. Counts for 2/3 of the Writing score) and GRAPH DESCRIPTION (150 words: in 20 minutes. Counts for 1/3 of the Writing score). You will have 1h to complete both tasks on the day of the exam.

* ESSAY: Write an essay about humans relationship with plants, being used as medicines, in art etc
* GRAPH DESCRIPTION:
Percentage of Biotechnology Firms by Application: “Biomolecular engineering is the application of engineering principles and practices to the purposeful manipulation of molecules of biological origin. Biomolecular engineers integrate knowledge of biological processes with the core knowledge of chemical engineering in order to focus on molecular level solutions to issues and problems in the life sciences related to the environment, agriculture, energy, industry, food production, biotechnology and medicine.” (Source: wikipedia)
This graph shows us percentages of biotech firms by application. Summarise the  information by selecting and reporting the main features, and make comparisons where relevant.

For IELTS (General format), please select the ESSAY topic (250 words) and LETTER (150 words). You will have 1h to complete both tasks on the day of the exam.

* ESSAY: Write an essay about humans relationship with plants, being used as medicines, in art etc.
* LETTER: Write a letter to the council asking for a flower garden to be built in your neighbourhood. Discuss the benefits this could have for the community.

For FCE, please select 2 of the following: ESSAY, LETTER/EMAIL, REPORT, or REVIEW. You will have 1h20 to complete the tasks on the day of the exam.

* ESSAY: Write an essay about humans relationship with plants, being used as medicines, in art etc.
* LETTER: Write a letter to the council asking for a flower garden to be built in your neighbourhood. Discuss the benefits this could have for the community.
* REVIEW: You have just read an article on the decline of honey bees. One of the causes considered is the constant transportation of honey bees to warmer climates in order to keep them working and producing honey. Write a review of this method and how denying them hibernation is lowering the numbers.
* REPORT: Write a report on how deforestation and global warming are impacting on plant life, and affecting the environment and life on the planet…

For CAE, please select 2 of the following: ESSAY, LETTER/EMAIL, PROPOSAL, REPORT, or REVIEW. You will have 1h30 to complete the tasks on the day of the exam.
* ESSAY: Write an essay about humans relationship with plants, being used as medicines, in art etc.
* LETTER: Write a letter to the council asking for a flower garden to be built in your neighbourhood. Discuss the benefits this could have for the community.
* REVIEW: You have just read an article on the decline of honey bees. One of the causes considered is the constant transportation of honey bees to warmer climates in order to keep them working and producing honey. Write a review of this method and how denying them hibernation is lowering the numbers.
* PROPOSAL:  Write a proposal to a museum about a plant and insect exhibition. Discussing what can be gained by the public becoming more knowledgeable about insect and plant life on this planet
* REPORT:  Write a proposal to a museum about a plant and insect exhibition. Discussing what can be gained by the public becoming more knowledgeable about insect and plant life on this planet.

For TOEFL, please select the ESSAY topic and write a second essay response based on either the READING or LISTENING passage of the lesson. You will have 50 minutes to complete both essays on the day of the exam.

* ESSAY:  Write an essay about humans relationship with plants, being used as medicines, in art etc
* ESSAY: Essay response based on either the reading or listening passage of today’s lesson (Insects & Plants): Based on the reading, what are the pros and cons social insect colonies? How do these pros and cons translate to human interaction?