Unit 7 Gymnosperms Student Guided Notes
Vascular Plants with Seeds
General Characteristics of Seed Plants
There are two main groups of seed plants, ___________________________________.
The ______________ in both _____________________________________________
______________________________________________________________. The
advantage to having a seed is that the ______________________________________
______________________________________________________________________
________________________________ in comparison to those of the angiosperms.
They are ______________________________________________________________
______________________________________________________________________
______________________________________________________________________
_____________________________.
The following structures are found in seed plants and are very important in their
adaptation to living on land.
_________________
_________________
_________________
_________________
These structures and their functions will be the topics of the lessons to follow.
Seeds and Roots
The seeds ______________________________________________________. The
_______________ within these seeds is ____________________________________
_________________________ The seeds are diploid and _______________________
____________________________________________________________
In Douglas-fir, the seed is filled with 60% lipids, 16% proteins, and 2% sugars, making it
a high-energy and nutritious tissue.
Roots have three primary functions.
First, ___________________________
________________________________
_____________. They are the principle
water-absorbing organs of a plant.
________________________________
___________________________________________________ of the root and have
greater contact with soil particles. Secondly, __________________________________
_________________________________________________________________. This
prevents it from blowing away or falling over. Finally, ___________________________
_______________________________________________________.
This _________________________________________________________________.
Some roots may become specialized below-ground storage organs (example: carrot!).
This storage of energy is an
important strategy for surviving stress
and dormancy.
To the right is an image of the crosssection of a root.
__________________
_____________________________
_____________________________.
Roots grow by increasing in length
through cell division. The root tip
elongates and matures. The
structures in the root cross-section
are described below.
Epidermis (outer cells).
Cortex (loosely packed parenchyma cells).
Endodermis (inner cells).
The endodermis contains a layer of a waterproof substance that stops further
movement of water into cells. For water to get into the root it must pass through a
selectively permeable membrane. The innermost tissues are vascular tissues that
transport water, minerals and food. The outermost layer is the pericycle. Lateral roots
are formed by the division of pericyle cells.
Stems
_____________________________________
_____________________________________. They hold up leaves and flowers to the
light. Stems also ________________________________________________________
___________________________________________________________.
Cactus stores water.
Sugar cane stores large amounts of sugar.
The diagram above illustrates how sugars made in the leaves move into the phloem and
how water from the roots is moved up into the stem by xylem.
Leaves
______________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________.
Most leaves are thin and flat. Others are more needle like in appearance.
Leaf Structure
______________________________________________________________________
_________________________________________________. Spongy mesophyll
allows oxygen, carbon dioxide and water to diffuse in/out of the leaf. Notice the
location of the stomata and guard cells in this diagram.
Stomata
______________________________
______________________________
____________________ two kidneyshaped _______________________
______________________________
______________________________.
Stomata are ____________________
______________________________
_______________. This opening and
closing is regulated by the amount of
water in the guard cells. When guard
cells are ‘full’ of water they swell, making them spread apart to create an opening. The
______________________ necessary for photosynthesis can enter the leaf through the
stomata and the _________________ produced by photosynthesis can pass out of the
leaf through the same opening. _______________________________ is also lost in the
process of transpiration.
Cottonwood trees lose 100 gallons of water on a hot day.
Gymnosperms
Diversity of Gymnosperms
Gymnosperms includes four divisions of plants: _______________________________
__________________________________________________. The Pinophyta or
conifers are the most widely studied. They are the largest group and are the base of the
________________________________________________. All conifers have no
protecting ovary wall around the seed. In fact, ________________________________
______________________________________________________________________
______________________.
_______________________________ adaptations that allow them to live on land
include;
-Alternation of generations.
-______________________________________________________.
-Seeds contain fully formed plant embryo.
-Gymnosperms can store food.
-_______________________________________________________________
________________________________________________________________.
-________________________________________________________________
____________________.
-Contain Vascular tissue
that allows plants to grow
to great heights giving an
advantage in the fight for
sunlight.
Here's an image of the vascular
tissue within the trunk of a tree
that moves water and nutrients. It
is like a circulatory system for a
tree.
Cycads - Division Cycadophyta
The cycads are __________________
______________________________
than they are as a living species with
most of the fossils dating to the time of
the dinosaurs in the Mesozoic era.
Most cycads resemble palms and are
very slow growing. In cycads, _______
______________________________
______________________________
are formed.
Ginkgo - Division Ginkgophyta
Ginkgo biloba is____________________________
_________________________________________
______________________. There are male and
female trees which could easily be mistaken for
angiosperms. The trees have small flat leaves and
produce seeds that look like fruit. However, like
gymnosperms pollination is by wind and ciliated
sperm swim from the pollen tube to the egg in the
archegonium. They are ______________________
_________________________________________
______________________ but only the males are
planted typically because the females have a pungent smell when they produce seed.
Gnetophytes - Division Gnetophyta
There are three groups within
Gnetophyta and all three are fairly
strange shrubs. They are the most
closely related to angiosperms of all of
the living gymnosperms and they
even undergo double fertilization
which is a defining characteristic of
angiosperms.
Conifers - Division Pinophyta
Conifers received this name due to their _____________________________________.
Well known conifers include the cone bearing _________________________________
______________________________________ Their ___________________________
___________________________________ and don't bear much resemblance to
leaves macroscopically which is why ________________________________________
______________________________________________________________________
______________________________________ and most conifers retain their needles
in winter and continue to photosynthesize with a reduction in activity.
Here is an image of pine needles. The needles are in bundles of two so it could be a
lodgepole or jack pine.
Life Cycle of Gymnosperms
_____________________________________, as in other seed plants, ____________
___________________________________________________________. However,
is____________________________________________________________________
_____________________________________________________________________.
The seed of a gymnosperm _______________________________________________
______________________ to keep it from drying out so that the embryo can survive
long periods before growing. ______________________________________________
__________________________________________. When the seed lands on the
ground it will grow into the dominant
sporophyte tree. Once mature, this
tree will bear male or female cones.
On trees that have both male and
female cones, the male cones are
located on lower branches near the
tips to avoid self-fertilization. This
allows the pollen (n) of the male
cones to float to another tree on a
windy day giving cross-fertilization.
When a pollen grain lands on an
ovule of a female cone (n), ______
____________________________
____________________________
____________________________
______________________________________________________________________
There are two sperm produced by each pollen grain. One sperm eventually fertilizes the
egg and the other degenerates. Once the egg is fertilized forming a zygote (2n), it will
grow into a seed ready to become a new sporophyte tree.
Economic Importance
In first world countries the primary woods used for construction are gymnosperms. The
gymnosperms are known in the ___________________________________________.
The softwood lumber industry is ________________
_________________________________________
with most of the wood going to the USA. __________
_______________________________________ are
all examples of conifers used around the world for
__________________________________________
__________________________________________.
This is the primary economic importance of
gymnosperms as most do not produce edible fruits or
roots and the stem tissue is too woody for
consumption. However, there are a few examples of gymnosperms that are consumed.
______________________________________________________________________
________________________, due to its colour and hardiness, but its blossoms are
also used for the production of gin. Many other gymnosperms are used in landscaping
gardens but it is usually to provide a backdrop or contrast to the beauty of an
angiosperm.
Pine beetle infestations have been of particular concern to the logging industry in the
past decade.