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Some Clues to Describing and Understanding Organisms

Here are some clues to describing and understanding organisms to help focus your biodiversity research, in these three places:

  • in the classroom (as you form your questions and build hypotheses)
  • in the field (as you observe and collect data),
  • in the "lab" (back at school, as you analyze data, create graphic presentations, and review hypotheses)

(Remember: Some clues can be seen only close-up in the lab, but with practice, you'll see many in the field.) 
After noting a characteristic of the organism, always ask yourself, "Why might it be this way? What might this clue indicate?"

For all organisms, consider microhabitat: 
Does the organism always occur in the same "zone"? 

Consider:

  • temperature
  • moisture level
  • sunlight/shade
  • soil type

Plants 

Distribution:

  • Does it occur in clumps, or is it on its own, far from others of the same species?
  • If in clumps, do they seem randomly distributed, or do you see a pattern?
  • Is it always associated with the same plant species, or do you find it with a variety of other plants?

Growth Form:
How does the plant hold itself up when it doesn't have a skeleton?

  • Is it woody or herbaceous (non-woody)?
  • If it's woody, is there one main trunk (trees), or are there several (shrubs)?
  • Does the plant stand up by itself, sprawl along the ground, or use something else for support (vines)?

Leaf Type: Does the leaf look like:

  • a regular broad-leaf, with a little stem (petiole) and a flat, wide blade?
  • a long strap?
  • a needle or a tiny scale?
  • If the leaf has a petiole and blade, what shape is the blade?

Leaf Arrangement: How are the leaves arranged on a stem?

  • Are there two leaves attached to the same part of the stem (opposite)?
  • Are there more than two leaves attached to the same part of the stem (whorled)?
  • Do the leaves attach to the stem in a zigzag or spiral pattern (alternate)?

Reproduction: How does the plant produce offspring?

  • Do you see flowers on the plant?
  • Where are the male and female parts of the flower?
  • How do you suppose the male parts meet the female parts?
  • Do you see fruits or cones on the plant?
  • If so, can you find the seeds?
  • How do you think seeds get around to new locations?

Plant Defense: How do you suppose plants protect themselves from predators when they can't run away?

  • Does the plant have any spines?
  • Do the leaves look very hairy?
  • Are certain parts of the plant very tough and hard to digest?
  • Does the plant have a distinct smell?
  • Do you see anything eating the plant, or signs that something has been eating it?

Arthropods 

Behavior: Look for clues to how and where it earns its living, for example:

  • Is constantly visiting flowers?
  • Does it run around in the open?
  • Is it found only in the dark, under stones or logs?
  • Does it lie waiting in some kind of trap?

Location: Look for clues to the kind of places it prefers.

  • If on vegetation, is it chewing leaves? Piercing? Sucking?
  • Is it always on the same type of plant?
  • Does it occur in large numbers or on its own?

Occupation: What's it up to? For example:

  • Is it involved with another arthropod?
  • Is it eating? Is it being eaten?
  • Is it just "hanging out"?
  • Is it mating? Is it laying eggs?
  • Is it tending to eggs or larvae?
  • Is it carrying eggs or larvae?
  • Is it fighting? Showing off ("displaying")?

Morphology: How's it built?

  • Mouthparts: How do you think it might feed? Might it suck? Pierce? Bite? Does it have poison fangs?
  • Legs and other appendages: How long are they? How long are legs compared to other appendages? (For example, does it have huge rear legs like a grasshopper? Or a long "stinger" like an ichneumonid wasp?)
  • Eyes: How big are they? How complicated? (For example, does it have huge compound eyes like a dragonfly? Or tiny, simple eyes like many spiders?)

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