QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTION
What are protists? (what are they "not") - ANSWERSA paraphyletic
grouping that
includes all eukaryotes
except **the land
plants, fungi, and animals (!)**
What three lineages of Eukarya are generally excluded from the term "protist" -
ANSWERS1. Fungi
2. Animals
3. Land Plants
What is paraphyly vs monophyly? Explain why the term protist is paraphyletic -
ANSWERS- A monophyletic taxon is one that includes a group of organisms descended
from a single ancestor , whereas paraphyletic taxon is one that includes the most recent
common ancestor, but not all of its descendents.
- Protists refer to a
paraphyletic
group—they
represent some, but not all, of the
descendants of a single common ancestor.
• There is
no trait that
is found in "protists" but no other organisms.
• The common feature among protists is that
they tend to live in environments where they are surrounded by water.
Examples of the importance of studying protists - ANSWERS- medicine
- agriculture
- ecosystem
What is the distinction between phytoplankton and zooplankton? -
ANSWERSPhytoplankton depends on sunlight for making their food, they primarily live
on the surface of the water, while zooplankton lives in the darker and colder area of the
water body. Being in the category of plants, Phytoplankton releases oxygen into the
,atmosphere, whereas zooplankton does not have such function and eat the
Phytoplankton.
Why is phytoplankton so critical to the aquatic food chain? - ANSWERSPhytoplankton
are vital to marine ecosystems. They are producers, or autotrophs, that form the
foundation of most marine food webs. As photosynthetic organisms, they are able to
convert solar energy into chemical energy and store it as sugars.... Phytoplankton are
eaten by other small organisms, such as zooplankton.
Why is phytoplankton so critical to the global carbon cycle? - ANSWERSThese tiny
organisms consume carbon dioxide from the atmosphere (through photosynthesis) and
move it to marine sediments in the deep ocean in a process called "the biological
pump". Even small changes in the growth of phytoplankton may affect atmospheric
carbon dioxide concentrations, which would feed back to global surface temperatures.
• Protists play a key role in the global carbon cycle and act as
carbon sinks
that could help reduce global warming.
- A carbon sink is a long-lived carbon reservoir.
• Carbon sinks produced by protists can be either:
- Sedimentary rocks (like the Marcellus shale!)
- Petroleum
Evidence connecting green algae to modern land plants - ANSWERS• Green algae
have traditionally been
considered protists, but we study them
along with land plants for two reasons:
1. They are the closest living relatives to
land plants.
2. The transition from aquatic to terrestrial
life occurred when land plants evolved
from green algae.
Bryophytes - ANSWERS• mosses, liverworts, and hornworts
• waxy cuticle
• nonvascular
- grow in moist environments
• no flowers or seeds, flagellated
sperm
- need water for reproduction
and spores
• gametophyte dominant (1N)
- sporophyte develops from
gametophyte
,Seedless vascular - ANSWERS• like bryophytes: wet, humid places, require water for
fertilization
• unlike bryophytes: vascular tissue, sporophyte is free-
living
Seeded vascular plant (gymnosperms - naked seeds) - ANSWERS• seeds don't form
inside an ovary
• four groups:
- conifers
• woody trees, shrubs
• evergreen
- needlelike leaves
• cones:
female, woody
• strobilus:
male, not
woody
- cycads
• 130 species
- tropical or subtropical habitat
• pollen and seed bearing strobili form on separate plants
- ginkgos
• Ginkgo biloba
only surviving ginkgo species
• distinctive fan-shaped leaves
• male or female trees
• female trees produce seeds covered with a
fleshy, foul-smelling coat
- gnetophytes
• tropical trees, leathery vines and desert shrubs
• Ex) Welwitschia
and Ephedra
Seeded vascular plant (Angiosperms) - ANSWERS• flowering plants
• ovules and seeds
are enclosed in an
ovary
• three major groups:
- magnoliids
- eudicots
- monocots
, Vascular Plants - ANSWERS• majority of modern plants
• have vascular tissue
- Xylem (water transport)
- Phloem (nutrient transport)
• two groups:
- seedless vascular
• lycophytes, horsetails, ferns
- seed-bearing vascular
• gymnosperms, angiosperms
Adaptations to land - what are the major adaptations to land that have occurred over the
course of plant evolution? - ANSWERS• WATER:
- supportive medium
- plant has direct
access to water and
minerals
- photosynthesis in all
cells
- light may be limiting
• AIR:
- no supportive medium
- aerial parts of plant not in
contact with water source
(lose water to air)
- photosynthesis in aerial
parts of plant
- light not usually limiting
Adaptations to Land
Characteristics of Land Plants - ANSWERS• waxy cuticle
• roots
• shoots
• vascular tissues
• pollen grains and seeds
Plant Life Cycle Terms
Alternation of Generations - ANSWERS• Gametophyte:
haploid (1N)
make
gametes
via mitosis
• Sporophyte:
diploid (2N)
makes
spores