Curriculum Map 70 - BIOLOGY JUNCTION

Preap Cell Study Guide

Cell Structure & Function Review

1. The first Person to describe microscopic organisms and living cells was
________________________________.

2. The maximum size to which a cell may grow is limited mainly by the cell’s ___________________________ ____________________________.

3. Short, hair-like organelles that can move and may cover a unicellular organism or line the respiratory tract are called ______________________________________.

4. Some Ribosomes are free in the cytoplasm, while others line the membrane of the
_________________ __________________ __________________________.

5. Everything between the cell membrane and the nucleus, is the cell’s
____________________________________.

6. All cells, from all organisms, are surrounded by a _______________ _____________________.

7. Membranes are _______________________ and have the consistency of vegetable oil.

8. The organelle that stores DNA and synthesizes RNA _________________________.

9. The organelle that processes and packages substances produced by the cell ______________________ _________________________.

10. The ____________________________ is the control center of the cell.

11. The DNA in the form of a long strand is called ______________________________.

12. Cytoplasm consists of two main components: ____________________________ and
______________________________.

13. The cell membrane functions like a ______________________, controlling what
__________________ and _______________________ the cell.

14. A lipid is a simple form of ________________________________.

15. There are many kinds of ______________________ in cell membranes; they help to move material into and out of the cell.

16. Scientist call the modern view of the cell membrane structure the
______________________________ ____________________ _________________.

17. The nucleus is surrounded by a double layer membrane called the
__________________________ _________________________________.

18. During cell division, _________________________ strands coil and condense into thick structures called _____________________________________.

19. The nucleoli make ___________________________. Which in turn build proteins.

20. Membranes are made mostly of ___________________ and ______________________.

21. The _________________ is the smallest unit that can carry out all of the processes of life. The basic unit of life.

22. The maximum size to which a cell may grow is limited mainly by the cell’s ___________________ ____________________.

23. The discovery of cells is linked most directly the development of the __________________________.

24. Organisms whose cells never contain a membrane bound nucleus are called _____________________________________.

24. Suspended in the cell’s cytosol are tiny ___________________________________.

25. Cell membranes consist of two phospholipid layers called a ___________________.

26. The chromosomes in the nucleus contain coded _____________________ that control all cellular activity.

27. When a cell prepares to reproduce the _______________________ disappears.

28. Cytosol is a jelylike mixture that consists mostly of _____________________.

29. The nucleus is one ______________________________.

30. In Eukaryotic cells, most organelles are surrounded by a _____________________.

31. Organisms whose cells always or usually contain a nucleus or nuclei are called
____________________________________.

32. ________________________ are structures that carry out specific functions in the cell.

33. Most cells have a single ______________________; some cells have more than one.

34. Unicellular organisms such as bacteria and their relatives are ___________________________.

35. The Fluid Mosaic Model presents the modern view of a
__________________ ___________________________.

36. The “Blueprints” in a Cell that controls all its activity are the ___________________.

37. Where are poisons and waste detoxified in a cell? _________________________ _________________________________.

38. A cell synthesizes protein by using organelles called _______________________________.

39. The Mitochondria of a cell contain an inner membrane called _____________________________.

40. What are the membrane-bound sacs that package and secrete cell products?
___________________________ ___________________________.

41. Unlike animal cells, plant cells have ______________ ________________.

42. A Chloroplast can convert _________________, __________________________, and ____________________________ into ________________________.

43. What are Flagella? ___________________________________________________.

44. In animal cells, the Cytoskeleton maintains three-dimensional structure and helps the cell ___________________________.

45. The organelle that digest molecules, old organelles, and foreign substances in the cell _______________________________________.

46. A pigment that absorbs energy in sunlight ________________________________.

47. The organelle that prepares proteins for export and synthesizes steroids is ________________________ ________________________.

48. Ribosomes differ from most organelles because they have no ___________________________.

49. What type of cells would you expect to find large numbers of mitochondria? _______________________ _________________.

50. The “Powerhouse” of the cell _______________________________.

51. Short, hairlike organelles that can move and may cover a unicellular organism or line the respiratory tract are called _______________________________.

52. The first cells on Earth were likely _______________________ that did __________ make their own _________________.

53. Microfilaments and microtubules function in cell _______________________ and ____________________________.

54. What is the correct order of structures in living things, from simplest to the most complex? ______________________, __________________________, ______________________________, ______________________________.

55. The is the organelle that transfers energy in ATP _______________________________.

56. What word means “Water Fearing”? ____________________________.

57. What word means “Water Loving”? _____________________________.

58. What is cell specialization? Give an example.
59. Distinguish between the structure of rough ER and that of smooth ER.

60. Explain how ribosomes, endoplasmic reticulum, Golgi apparatus function together in protein synthesis.

61. Explain the difference between a tissue and an organ.

62. Why is the cell membrane said to be selectively permeable?

63. If a cell has a high energy requirement, would you expect it to have many or few mitochondria? Explain your answer.

64. Describe TWO differences between prokaryotic cells and eukaryotic cells.

65. How can you determine whether a unicellular organism is a prokaryote or a eukaryote?

66. Plant cells have cell walls, but animal cells do not. Why do you think that is so?

67. What are the THREE Parts of the Cell Theory?

68. Describe three differences between plant and animal cells.

69. Name the TWO different kinds of animal cells, and describe how their shape is related to their function.

70. What is the difference between chromatin and chromosomes?

71. What are the major roles of the nucleus, and what parts of the nucleus carry out these roles?

72. What is a colonial organism, and what does it have in common with multicellular organisms?

Plant Classification Study Guide

PLANT EVOLUTION AND CLASSIFICATION

1. There are more than ________________ different plant species.

2. Plants share Four Characteristics:
A._________________________________________________________________

B._________________________________________________________________

C._________________________________________________________________

D._________________________________________________________________

3. In their characteristics plants are most similar to the ________________________.

4. Plants and Green Algae Have these Characteristics in Common:
A.__________________________________________________________________

B.__________________________________________________________________

C.__________________________________________________________________

D.__________________________________________________________________

5. There are also some important Difference:
A.__________________________________________________________________

B.__________________________________________________________________

C.__________________________________________________________________

D.__________________________________________________________________

6. All plants are photosynthetic, multicellular, __________________________ organisms, and can _________________________ _________________________.

7. A ____________________ is a ripen ovary that surrounds the seeds of angiosperms.

8. All plants probably evolved from ______________________ __________________.

9. One of the greatest problems that encountered by the first land plants was the need for
___________________________.

10. How does water aid the fertilization of some organisms? ______________________
____________________________________________________________________

11. _________________________ of _______________________ means that there are TWO
phases in the life cycle of plants:

A. The first phase: ___________________ ______________________ phase that produces ________________________ and _______________________.

B. The second phase: ___________________ _____________________ phase that produces ________________________.

12. Sexual reproduction ensures there will be __________________________ ______________________ in plants.

13. The type of vascular tissue that transports organic compounds is ____________________________.

14. The _____________________ is a waxy, waterproof layer that coats the parts of a plant
exposed to air.

15. The earliest plants were probably __________________, and had NO true ___________,
____________________, or ______________________.

16. __________________ is a hard compound that strengthens cell walls, enabling cells to support additional weight.

17. The 12 Phyla of plants can be divided into two groups based on the presence of __________________________ ___________________________.

18. One adaptation that help land plants to slow the evaporation of water was a
____________________________.

19. The type of vascular tissue that transports water is _________________________.

20. This type of angiosperm has parallel leaf venation __________________________.

21. The waxy covering on plant surfaces is called _____________________________.

22. The plant material in peat bogs decomposes very ________________________ because the bogs are ____________________________.

23. How many plant phyla produce seeds? _____________________

24. What type of gymnosperm produces fleshy seeds? ____________________________

25. What is the photosynthetic phase of a moss called? ______________________________

26. Bryophytes, instead of roots, they have long, thin strands of cells called ____________________ that attach the plant to the soil.

27. Vascular plants absorb water from the soil through underground structures called
_____________________. They also provide a plant with ___________________.

28. Non-woody plants are usually called ___________________________.

29. _____________________ carries organic compounds in any direction depending on the plant’s needs.

30. In order to reproduce, a nonvascular plant must have ________________________.

31. Rhizoids are long, thin strands of cells that resemble ________________________.

32. The roots of vascular plants absorb water and _________________________ _________________________.

33. What is the non-photosynthetic phase of a moss called ____________________________.

34. Gymnosperms produce “_____________________” seeds, while angiosperms produce _______________________ protected inside a _____________________________.

35. This type of angiosperm has net leaf venation __________________________.

36. The _________________________ allow for the exchange of carbon dioxide and oxygen.

37. Sphagnum is often used to ______________________ soil and help it ____________________ __________________________.

38. A ___________________ is a protective structure that contains a plant
__________________, and _________________ __________________.

39. A __________________ is a structure that develops in plants with flowers and contains the
____________________.

40. Nonvascular plants are distinguished by the absence of ______________________ and ____________________________.

41. All nonvascular plants are collectively called _______________________________.

42. Vascular plants are classified into one of Two Types: _______________________ or
________________________________ plants.

43. What are the Four Phyla of Seedless Vascular Plants? ________________________,
________________________, ______________________, ________________________.

44. What are the Five Phyla of Seed Vascular Plants? _______________________,
_________________________, _________________________,
________________________, and ______________________________.

45. Vascular seed plants are subdivided into TWO general categories according to the type of seeds they produce: _________________________________ and
____________________________________.

46. A ____________________________ is a special reproductive structure composed of hard scales, that produces seeds without a fruit.

47. ____________________ are vascular plants that produce seeds lacking a protective
_______________________. They are often called _______________ _________.

48. A seed is a _________________________ embryo inside a __________________________ _____________________.

49. The _____________________ are vascular plants that produce seeds enclosed and
__________________ by a __________________.

50. All angiosperms produce _________________ and _________________.

51. The protective structure that contains the seed or seeds of an angiosperm is the
______________________.

52. One way of distinguishing among the many types of angiosperms is by counting the number of seed leaves or ________________________.

53. Angiosperms with only ONE cotyledon are called _______________________________ or simply _____________________.

54. An angiosperm whose embryo has TWO cotyledons are called __________________________________ or simply _______________________.

56. Plants that produce seed protected by a fruit are called _______________________________.

57. A dicot is an angiosperm whose embryo has Two _______________________.

58. Plants remove carbon dioxide from the air by the process of ________________________.

59. Bryophytes are _______________-growing plants that live in _____________________ ________________________________.

60. All vascular plants have __________________________ tissues and _____________________________ of _________________________________.

61. True roots, stems, and leaves are characteristics of all ______________________ _________________________.

62. What are the primary functions of spores and seeds?

63. In what ways do green algae differ from plants?

64. Why do nonvascular plants have to live in moist environments?

65. Name three bryophytes, and identify their common characteristics.

66. Which plant phylum contains the tallest and most massive plants? Is this a phylum of nonvascular, seedless vascular, or seed plants?

67. Conifers are often found living at high elevations in locations with cold, dry winters. What characteristic enables them to retain their leaves in these conditions?

Plant Reproduction

PLANT REPRODUCTION
All Materials © Cmassengale

PLANT LIFE CYCLES:

A life cycle includes all of the stages of an organism’s growth and development
A plant’s life cycle involves two alternating multicellular stages – a Diploid (2n) sporophyte stage and a Haploid (1n) gametophyte stage
This type of life cycle is called Alternation of Generations

Moss Characteristics:

Nonvascular (pass water cell-to-cell)
Seedless (reproduce by spores)
Low growing
Phylum Bryophyta (also includes liverworts & hornworts)
Grow on moist brick walls, in sidewalks, as thick mats on forest floors, and on the shaded side of trees

Can survive periodic dry spells, reviving when water becomes available
Require water for fertilization so sperm can swim to egg
Rhizoids (root like structures) anchor mosses
Have waxy covering called cuticle on aerial parts to prevent desiccation

Moss Life Cycle:

Dominant form of a moss is a clump of leafy green gametophytes (photosynthetic)
Moss alternates between a haploid (1n) gametophyte and diploid (2n) sporophyte
Gametophyte generation produces gametes (eggs & Sperm)
Sporophyte generation forms at the top of the gametophytes and produces spores
Stalk-like sporophytes lack chlorophyll
Capsule at the top of the sporophyte forms haploid (1n) spores

Sexual reproduction in Moss:

Moss produce 2 kinds of jacketed gametes — eggs & sperm
Egg producing organ is called the archegonium
Eggs are larger and nonmotile
Sperm producing organ is called the antheridium
Sperm are smaller, flagellated cells
Antheridia & archegonia are both part of the gametophyte plant
Fertilization can occur only during or soon after RAIN when the gametophyte is covered with Water
Sperm swim to the egg by following a trail of chemicals released by the egg in the water
Fertilization produces a zygote that becomes a sporophyte
Mature sporophytes produce homosporous spores (all the same type)
Mature capsules open & release spores spread by wind
Spores landing on moist places germinate into protonema that become new gametophytes

Asexual Moss Reproduction:

Small pieces may break off from a gametophyte & become a new plant (fragmentation)
Small buds called gemmae may be washed off by rain and develop new moss plants

Fern Characteristics & Life Cycle:

Largest group of seedless, vascular plants
Grow in moist places
Goes through alternation of generations
Sporophyte phase is the dominant stage
Fern gametophytes are small, flat plants anchored to the soil by root-like rhizoids
Antheridia & archegonia form on the underside of fern gametophytes

Sperm swim to egg through water droplets to form zygote (fertilized egg)
Zygotes form new sporophytes with roots, stems, & leaves
Spore cases called sori form on the underside of fern fronds (leaves)

Ferns are homosporous (single type of spore formed)

New fronds form from an underground stem called the rhizome
Vascular tissue carries nutrients & water between the parts of the fern
Fronds are compound leaves attached by a short stalk called the stipe to the underground stem or rhizome

Immature fronds or fiddleheads are coiled

Characteristics & Life Cycle of Conifers:

Called gymnosperms
Have naked seeds that develop on scales of the female cones
Sporophyte is the dominant stage
Adapted to cooler climates
Called evergreens (pine, cedar, spruce, fir…)
Giant Redwood is one of the Earth’s largest organisms
Bristlecone Pines are the oldest living organisms (some more than 5000 years old)


Giant Redwood	Bristlecone Pine

Produce 2 types of spores (heterosporous)
Male spores called microspores grow into male gametophytes
Female spores called megaspores grow into female gametophytes
A Pine cone is the female cone on a pine tree
Male cones on pine trees are smaller & grow in clusters at the tips of branches
Both male & female cones appear on the same tree


Female Cones	Male Cones

The pine life cycle takes 2-3 years from the formation of cones until seeds are released
Female cones have spirally-arranged scales with ovules at their base
Female cones produce sticky resin
Ovules contain an egg that will develop into a seed
Male cones produce large amounts of pollen in the spring that is spread by wind to the female cones
Resin traps the pollen so pollination can occur
A tube from the pollen grain takes a year to grow to the ovule so a sperm can fertilize the egg and form seeds

Angiosperms or Flowering Plants:

Bright colors, attractive shapes, and fragrant aromas help flowering plants attract their pollinators (insects, birds, mammals…)
Flowers without bright colors and pleasing odors are usually wind or water pollinated (grasses)
Called angiosperms
Flowers, the reproductive part of a plant, have a swollen base or receptacle to attach to the stem
Flowers have 4 whorls (modified leaves) attached to the receptacle — petals, sepals, pistils, and stamen
Pistils (innermost whorl) are the female part of the flower, while Stamens are the male part
Sepals (outermost whorl) are found below the petals and may look leaf-like (some may be the same color as petals)
Sepals enclose the flower bud before it opens
Sepals are collectively called the calyx
Petals are often colorful to attract pollinators
Petals are collectively called the corolla

Monocot flower parts are arranged in multiple of THREES, while dicots are in multiples of FOUR or FIVE
Perfect flowers have both stamens & pistils (rose)
Imperfect flowers are either a male (pistillate) or female (staminate) flower (pumpkin or melons)
Some angiosperms have both male & female flowers on the SAME plant (monoecious)
Other angiosperms have entire male OR female plants (dioecious)

Female Reproductive Structures:

Called carpals
Carpals may be fused to form the pistil
Produce eggs
Composed of 3 parts — stigma, style, and ovary
Stigma is located at the top and may be sticky or have hairs to hold pollen grains landing there
Style is a stalk-like connection between the stigma and the ovary
Ovary is the enlarged base containing ovules with eggs

Pistil

Male Reproductive organs:

Called stamens
Produce pollen
Composed of 2 parts — filament & anther (pollen sac)
Anthers produce pollen grains containing sperm
Filament is stalk-like & supports the pollen sacs

Stamen

Angiosperm Life Cycle:

Undergo alternation of generations
Sporophyte is dominant phase
Gametophytes (flowers) form male & female gametes
Anthers form pollen grains from microspores
Pollen grains contain 2 cells — tube cell & generative cell (sperm)
Two protective layers called integuments surround the megasporangium
The entire structure including the integuments is the ovule and becomes the seed
Each ovule has 4 megaspores (three disintegrate)
The remaining megaspore undergoes mitosis to produce a large cell & polar nuclei
When pollen lands on the stigma, a pollen tube grows through the style to the ovary
Two sperm travel down the pollen tube — one fertilizes the egg and the other join with polar nuclei to form endosperm (stored food for Seed)
Called Double Fertilization

After fertilization, ovule becomes the seed and the ovary & surrounding tissues form a protective fruit
A fruit is a ripened ovary with seeds (apple, melon, cocklebur…)
When seed land on moist soil, they germinate (sprout) and form new sporophyte plants

Pollination:

Wind, water, and animals help spread pollen
As pollinators drink nectar or eat the fruit, pollen gets on their bodies and is spread to other flowers
Self pollination occurs whenever pollen from a flower lands on the stigma of that SAME flower (pea plants)
Cross pollination occurs whenever pollen is spread to a different flower producing hybrids (more gene combinations)

Seeds & Fruit:

Fruits are adaptations for dispersing seeds (coconuts float, cockleburs catch onto animal fur, some seeds eaten by birds aren’t digestible…)
More energy is required to produce seeds than spores because they contain stored food
Seeds may be dormant (inactive) for weeks or years protected by their seed coat
Seeds contain a plant embryo and endosperm

Many fruits are fleshy & their seeds aren’t digested by the animals that eat them
Heavy seeds have adaptations such as wing-like structures (maple) or prickly coats (cocklebur) to help them disperse


maple seeds	Cockleburs	Coconut

Fruits may be dry or fleshy
Three types of fruits exist — simple, aggregate, & multiple
Simple fruits (apple) form from One pistil on a flower
Aggregate fruits (raspberry) form from several pistils on a flower
Multiple fruits (pineapple) form several flowers growing close together
Cotyledons are leaf-like structures of the plant embryo
Monocot seeds have one seed leaf (Cotyledon), while dicots have two cotyledons

The epicotyl is the part of the plant embryo ABOVE the cotyledon & becomes the stem
The radicle is the part of the plant embryo BELOW the cotyledon & becomes the root
The hypocotyl is the part of the plant embryo BETWEEN the cotyledon & the radicle
The hilium is a scar along the seed edge where it was attached to the ovary
In monocot seeds like corn, a sheath called the coleoptile grows out of the ground to protect the newly emerging plant

Germination:

Many seeds require environmental factors, such as Water, Oxygen, and Temperature to trigger germination
Some seeds only germinate after exposure to extreme cold or after passing through an animal’s digestive tract
Water must FIRST be absorbed by the seed to break the seed coat & activate enzymes to change starch in the endosperm or cotyledons into simple sugars for energy
The radicle emerges first

Once the seed coat opens, OXYGEN is needed for cellular respiration carried on by the embryo plant
The shoot (hypocotyl & embryonic leaves) begin to grow, synthesize chlorophyll, and carry on photosynthesis

After the stored food is used up in dicots, the cotyledons fall off

Dicot Seed Germination

In Monocots like corn, the Cotyledon remains underground and transfers nutrients to the growing Embryo.

Asexual Reproduction in Plants:

Asexual reproduction is FASTER and produces well-adapted offspring
Called vegetative reproduction
Occurs from non-reproductive parts such as roots, stem, or leaves
Runners, Rhizomes, Bulbs, and Tubers can be used to produce new plants
Cutting is taking a piece of Stem or Leaf and growing a new plant
Grafting occurs whenever 2 cut ends of plant stems are fused
Layering occurs when aerial roots touch soil & start growing new plants

Plant Analytical Questions

Plant Analytical Questions

Plant Structures and Function

Part 1: Use the following diagram of a seedling to answer these questions.

What tropisms are being exhibited by the various parts of this seedling?

What hormones are involved in these responses?

Part 2: Use the diagram below to complete lines a – f.

The diagrams represent three conditions of day & night length. A short-day plant, with a critical night length of 14 hours, and a long-day plant, with a critical night length of 8 hours, are grown under each condition. On lines a – f, indicate whether each plant will flower under each condition.

Plant Taxonomy

Overview of Plants:

All plants are multicellular & contain chlorophyll inside of chloroplasts
Plants (also called autotrophs or producers) trap energy from the sun by photosynthesis & store it in organic compounds
Heterotrophs or consumers get their energy directly or indirectly from plants
Plants also release oxygen needed by consumers
All plants are multicellular, eukaryotic organisms that reproduce sexually
Many medicines are produced by plants
Plants are very diverse & may be terrestrial or aquatic
Vary in size from 1 mm in width to more than 328 feet
May live a few weeks or some over 5000 years
Kingdom Plantae is divided into 12 phyla or Divisions
More than 270,000 plant species identified, but new species still unidentified in tropical rain forests

Terrestrial Adaptations:

Plants probably evolved from green algae

Both algae & plants have chlorophyll a & b, have cell walls made of cellulose, and store energy as starch
First land plants had to develop adaptations to scarcity of water & climate changes (air temperature changes more rapidly than water temperature)
Moving onto land allowed more sunlight, nutrients, & CO2 for photosynthesis
A support adaptation included a compound called lignin (a hard substance that strengthens cell walls so they can support additional weight)
The origin of vascular tissue (specialized tissue for carrying food , water, & minerals) was an evolutionary breakthrough in the colonization of land
Plants with vascular tissue are known as Tracheophytes
Two types of vascular tissue developed — xylem & phloem

Xylem carries water & inorganic nutrients from the roots to the stem & leaves
Phloem carries carbohydrates made by the plants to wherever they’re needed or stored in the plant

Copyright Holt, Rinehart, & Winston

Some plants formed woody tissue from xylem for extra support, while others kept a flexible, non-woody stem (herbaceous plants)
Greater amount of water lost by evaporation (transpiration) on land
A waxy covering or cuticle developed on all plant parts exposed to air which slowed transpiration (water loss)

Gases (carbon dioxide & oxygen) had to be able to move into & out of the plant
Openings in the cuticle called stomata allowed movement of gases
Two guard cells on each side of a stoma helped open & close the opening

Copyright Holt, Rinehart, & Winston

When guard cells lose water & shrink, the stoma closes (prevents water loss in the hotter times of the day)
When guard cells swell with water, the stoma opens for gas exchange

copyright McGraw-Hill

Other structural adaptations to land included roots for absorption of water and minerals leaves for gas exchange and photosynthesis

Reproductive Adaptations:

To be successful on land, plants had to develop protective seeds for their embryos with stored food or endoderm

Copyright Holt, Rinehart, & Winston

Seeds are better at dispersal than spores

Classification of Plants:

They’re are 12 Divisions of plants divided into two main groups based on the presence of vascular tissue
Nonvascular plants lack vascular tissue and do not have true roots, stems, or leaves (mosses, liverworts, & hornworts)
Most plants have vascular tissue with true roots, stems, & leaves, but may or may not produce seeds

Copyright Holt, Rinehart, & Winston

Ferns, horsetails, & club mosses are seedless vascular plants that reproduce by spores
Plants that reproduce by seeds are divided into 2 groups — gymnosperms & angiosperms
Gymnosperms have “naked” seeds usually protected by cones & includes pines, cedars, spruce, fir …

Angiosperms are flowering plants whose seeds are produced & protected within the fruit

Plant Life Cycles:

Plants have 2 phases in their life cycle called alternation of generation
The haploid gametophyte stage produces eggs & sperm, while the diploid sporophyte stage produces spores

Copyright Holt, Rinehart, & Winston

Plant gametes are not directly produced by meiosis but rather by mitosis from the haploid multicellular stage
Meiosis instead produced specialized haploid cells called spores
These spores are released by most Seedless plants, but are retained by Seed plants
In nonvascular plants, the Gametophyte stage is dominant (mosses)

In vascular plants, the Sporophyte stage is dominant
Seedless vascular plants usually have a separate, small gametophyte plant
Sexual reproduction in plants ensures that there will be genetic recombination

Seed-Bearing, Vascular Plants:

The development of seeds with their protected embryo & stored food supply increased the reproductive success of seed plants
Seeds remain dormant or inactive when conditions aren’t favorable
Moisture & warmer temperature cause seeds to germinate or sprout
Young plant embryos use their endosperm as energy for early growth

Seeds plants are divided into 2 groups based on the type of seed they produce

Gymnosperms:

Gymnosperms produce seeds that not protected within an ovary
The seeds are exposed on the upper surfaces of a spore producing structure (e.g. cone scales in conifers)
Called “naked” seeds
Gymnosperms do not produce flowers or fruit
The four phyla of gymnosperms alive today include the cycads (Cycadophyta), the ginkgo (Gingkophyta), the gnetophytes (Gnetophyta), and the conifers (Coniferophyta)


Cycad	Welwitshcia (gnetophyte)	Gingko	Fir Tree (Conifer)

All gymnosperms have vascular tissue to conduct food, water & minerals and produce woody tissue
Two types of cones are made by gymnosperms — pollen cones & seed cones
Pollen cones are small & produce pollen containing the male gametophyte which is spread by wind or insects to the female gametophyte
Seed cones are larger and contain eggs on scales that form seeds when they are fertilized

Division Cycadophyta:

Dominated earth when dinosaurs lived, but only about 100 species are alive today & are endangered
Most are slow growing, palm-like plants found mostly in tropical areas
All cycads bear cones, which are made up of seed bearing leaves (sporophylls)
They have large compound leaves, a short thick trunk, and are dioecious (either male or female plant)
Cycads bear naked seeds

Zamia (native to Georgia)

Division Gingkophyta:

Ginkgoes were common in the Mesozoic period, but today only one species of ginkgo remains (Ginkgo biloba)
Gingko trees have distinctive fan shaped leaves & are dioecious (each tree is either male or female but not both)
Commonly planted as an ornamental tree
Gingkoes are not native to North America (they are found growing wild only in China)
Deciduous tree (loses leaves in fall) with plum-shaped, fleshy seeds with a foul odor

Division Coniferophyta:

Largest group of gymnosperms
Called conifers
Found in abundance in temperate zones
Include cedars, pines, spruce, fir, juniper, & bald cypress trees
Their leaves are characteristically needle-like, but may be scale-like
Usually trees or shrubs
Evergreens (don’t lose their leaves in the fall)
Almost all conifers are monoecious, producing both male and female cones on the same tree
Female cones are larger than male cones with woody scales containing the seeds


Pollen Cone	Seed Cone

Conifers are dependent on the wind for pollination
Pollen grain has air bladders to help it stay aloft in the wind
Important source of wood, paper, turpentine, ornamental plants, Christmas trees
Redwoods and Giant Sequoia trees are the largest living organism on earth
Bristlecone pines are the oldest living organism on earth


Redwood Tree	Bristlecone pine Tree

Division Gnetophyta:

The phylum Gnetophyta consists of 3 genera that are not very closely related
Ephedra is the largest genus and consists of plants that resemble horsetails & grow in deserts
Welwitshcia is found only in the desert area of south western Africa and has 2 single, long leaves


Welwitshcia	Ephedra

Division Anthophyta (Angiosperms):

Flowering plants are the most successful group of plants today
They live in almost all possible habitats
All flowering plants produce both flowers & fruit

Fruit is a ripened ovary with its seeds (acorns, apples, dandelion seeds, etc)

Flowering plants co-evolved with their insect pollinators
May be herbaceous (grasses & snapdragons or woody (oaks & grape vines)
Rafflesia, the stinking corpse lily, is the world’s largest flower

Flowering plants have diverse lifestyles (Sundew is carnivorous on insects; Spanish moss is an epiphyte living on another host plant; some orchids are saprophytes living on soil fungi)
Subdivided into 2 classes based on the number of seed leaves or cotyledons in the plant embryo — Monocotyledons & Dicotyledons
Monocots have a single seed leaf, leaves with parallel venation, vascular tissue scattered in bundles throughout the stem, and flower parts in 3’s or multiples of 3

Dicots have a 2 seed leaf, leaves with net-veined venation, vascular tissue in rings in the stem, and flower parts in 4’s or 5’s multiples of 4 or 5

Monocots are usually herbaceous, while dicots often produce wood

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