Grouping of living things ：練習問題

What is the primary purpose of using a dichotomous identification key in biological studies?

A plant is observed to have a stem with vascular bundles arranged in a ring, leaves with net-like veins, and flowers with parts in multiples of four or five. Which class of flowering plants does it most likely belong to?

Consider a simple identification key for invertebrates:
1a. Has a hard outer shell .......................... Go to 2
1b. Does not have a hard outer shell ........ Go to 3
2a. Shell is spiraled ................................ Snail
2b. Shell is bivalve (two halves) ............ Clam
3a. Has segmented body and many legs ... Centipede
3b. Soft body, no legs ......................... Earthworm

An unknown organism is found with a soft, cylindrical body, no shell, and no legs. Following this key, what is the correct classification?

A botanist observes a plant that produces seeds enclosed within a fruit. Into which major plant group would this plant be classified?

A scientist compares the body structures of a dolphin and a land mammal. Which key feature of the dolphin is the most significant adaptation for moving efficiently through its aquatic environment?

What is the primary feature used to distinguish flowering plants from non-flowering plants?

Explain one key difference between a vascular plant and a non-vascular plant, relating it to their ability to transport water.

Biodiversity is crucial for the health of ecosystems. Explain why a decrease in the diversity of plant species in an area could negatively impact the animal populations living there.

Living things are often grouped based on observable characteristics. Consider the following animals: a frog, a spider, a bird, and a jellyfish.

a) Group these four animals into two main categories: vertebrates and invertebrates. (2 points)
b) For each category, state the key distinguishing feature that separates it from the other category. (2 points)

Scientists classify plants into different groups based on their structural features and reproductive methods. Consider two broad groups: mosses (non-vascular plants) and ferns (seedless vascular plants).

a) Describe two key structural differences between mosses and ferns that are important for their classification. (2 points)
b) Explain how one of these structural differences allows ferns to grow taller and thrive in a wider range of terrestrial environments compared to mosses. (3 points)