Activity 1.3 - The science of taxonomy

• Identify living organisms in the local ecosystem
• Develop observation and interpretation skills
• Construct keys using common features of organisms
• Inquire about scientific classification –taxonomy- of organisms
• Inquire about the life cycle of a living organism
• Inquire about the role of an organism in the ecosystem
• Use genetics to identify common features of organisms
• Discuss the theory of evolution based on DNA homologies

In the field

Beating Stick and Net

Aspirator

Killing Tube

Light Trap

Keys

Camera

Container

In the lab

Dissecting Microscope

Compound Microscope

Scanning Electron Microscope

DNA Sequencing homologies

Introduce the topic: The biodiversity of planet Earth is the total variability of life forms. Currently about 1.9 million species are known, but this is thought to be a significant underestimate of the total number of species. Every year, thousands of new species are discovered. Biologists use characteristics of each newly discovered species to classify organisms having similar characteristics. A classification system is used to assign a single universal name to each organism. Biologists in the field have to use their observation and interpretation skills to make deductions about the organisms they discover. This lets them build up an accurate picture of the role of the organism in its environment, how they interact with their surroundings and what threats they may face now or in the future.

Exercise 1

• Allow a team of five students to observe the environment around them. The students must use a field notebook to sketch the organisms that they discover, and take notes on their features including shape, coloring, and behavior. The students must write down when and where they found the organism, and any interesting information about its behavior. They must learn to be as precise as possible. If you can, use a field guide or a specialist (e.g., botanist, forester, zoologist) to identify what kind of organisms they have found. Let the students know that they must keep track of any questions that occur to them.
• Discuss with the team why the organism must be kept alive. If they capture a live insect, and they want to observe it for a short while before setting it free, they must put it in a clear container with enough room for it to fly around and to breathe.
• Return the organism to its natural habitat.
• Allow the students to take a photograph of any interesting organism and to start a photo album.
• Without the right tools, insects can be tricky to catch. Ask the students to search the network for homemade bug-catching devices they can make by themselves.
• Use a stereoscope or a microscope in the laboratory to identify any relevant characteristics.
• Record the characteristics of the organism.

Possible Questions:

1. Classify the organism you have discovered into one of the five kingdoms listed below:

4. Is it likely to be active at night or during the day?

5. a) Write the taxonomy of the species that you have discovered

• kingdom
• phyla
• class
• order
• family
• genus
• species

b) Its scientific name is ……………………………………………

c) Its common name is …………………………………………….

d) Who proposed a new system of classification?

Exercise 2

Construct a dichotomous key device that can be used to easily identify an unknown organism.

Introduction; The word dichotomous comes from two Greek words that together mean, "divided in two parts."  A dichotomous key consists of a series of two part statements that describe characteristic of organisms.  At each step of a dichotomous key, the user is presented with two choices.  As the users make a choice about a particular characteristic of an organism, they are led to a new branch of the key.  Eventually the users will be led to the name of the organism that they are trying to identify.

Exercise 3

Ask the students to inquire in the website for information about the role of the organism they have identified in the ecosystem.

• Gather responses and subsequent questions from students with little comment or direction.
• Allow students to collaborate in their team
• Student teams gather data.
• Re-evaluate question based on new data from all the teams
• Students present findings as an oral presentation, a poster presentation or an evaluative write-up.

Possible questions that will help the students inquire about the role of their chosen organism are :

1. The space where an organism lives and the role an organism plays within its ecosystem is referred to as a

A)   sampling

B)   population

C)   niche

D)   biome

1. An organism that creates its own food is called

A)   a producer

B)   a consumer

C)   a scavenger

D)   a decomposer

1. A consumer is

A)   an organism that produces its own food

B)   an organism that does not need food to survive

C)   an abiotic organism

D)   an organism that cannot produce its own food

1. Herbivores, carnivores and omnivores are

A)   plants, animals and micro-organisms

B)   three types of consumers

C)   three types of producers

D)   three of British Columbia's 10 eco-provinces

1. An organism that eats decaying plants and animals is called

A)   a decomposer

B)   a parasite

C)   a carnivore

D)   a scavenger

1. Parasitism, commensalism and mutualism are

A)   three examples of producers

B)   the three main types of symbiotic relationships

C)   the three main types of ecological relationships

D)   three examples of abiotic interactions

1. Which of the following is a symbiotic relationship where one partner benefits and the other does not benefit or lose from the relationship?

A)   commensalism

B)   mutalism

C)   parasitism

D)   decomposition

1. Which of the following is a symbiotic relationship where both partners benefit?

A)   mutualism

B)   parasitism

C)   commensalism

D)   symbolism

1. Which of the following is a symbiotic relationship where one partner benefits and the other is harmed?

A)   commensalism

B)   mutualism

C)   symbolism

D)   parasitism

Study visit

Genetics as well as simple observations are used in classification today. Visit a genetic institute to investigate how DNA analysis can provide evidence in a taxonomic study.

Introduction: In modern biology, it is not considered satisfactory to consider adaptations, evolution, speciation and physiology as autonomous topics, but an appreciation of other disciplines, such as biochemistry, is essential. The study of molecular evolution by comparing protein and gene sequences can integrate biology with chemistry and Physics.

Discuss the theory of evolution based on DNA homologies