Chapter 30 Plant Diversity 2 Flashcards
What is a seed?
Consists of an embryo and nutrients surrounded by a protective coat
What do all seeded plants have? (4 things)
- Reduced gametophytes
- Heterospory
- Ovules
- Pollen
What is reduced gametophytes?
Development within the walls of spores that are retained within tissues of the parent sporophyte
What is heterospory?
It is the rule among seed plants: modern seed plants are heterosporous but ancestors of seed plants are homosporous
What does megasporangia and microsporangia produce?
Megasporangia -> produces megaspores -> produces female gametophytes
Microsporangia -> Produces microspores -> Produces male gametophytes
What does the ovule consist of?
Consists of megasporangium, megaspore, and one or more protective integuments
- integuments are a protective layer
What is the difference b/w gymnosperm and angiosperm in terms of integuments?
Gymnosperm: Has one integument
Angiosperm: Has two integuments
What are pollen grains?
It contains the male gametophytes and is developed from microspores
What is pollination?
Transfer of pollen to the part of a seed plant containing the ovules
What are some advantages of seeds over spores?
- Remains dormant until there’s favorable conditions
- Seeds have a supply of stored food
- May be transported long distance by wind or animals
What are gymnosperms?
Naked seeds typically found on cones, i.e., conifers
- seeds are exposed on sporophylls
What are angiosperms?
Seeds found in fruit, also known as mature ovaries
What are 3 key features of Gymnosperm life cycle?
- miniaturization of their gametophytes
- development of seeds from fertilized ovules
- transfer of sperm to ovules by pollen
When did gymnosperm appear?
During the Mesozoic era cause they thrived in drier conditions
What does a seed develop from?
Develops from a whole ovule
What are the 4 types of gymnosperm phyla?
- Cycadophyta
- Ginkgophyta
- Gnetophyta
- Coniferophyta
What are 3 things of the Cycadophyta?
- large cones and palmlike leaves
- flagellated sperm
- surviving species are endangered
What are 3 things to remember for Ginkgophyta?
- consists of a single living species, Ginkgo Biloba
- Like the Cycads, this group also has flagellated sperm
- Has a high tolerance to air pollution and is a popular ornamental tree
What are 2 things to remember for Gnetophyta?
- Has 3 genera: Gnetum, Ephedra, and Welwitschia
- Species vary in appearance, and some live in tropical areas while other live in deserts.
What are 2 things to remember for Coniferophyta?
- Largest of the gymnosperm phyla
- Most conifers are evergreen and can carry out photosynthesis year round
What is the most widespread and diverse of all the plants?
Angiosperm
What are the 2 key adaptations of angiosperms?
- flowers
- fruit
What is a flower?
Angiosperm structure specialized for sexual reproduction, i.e., pollination
What are the 4 organs of a flower?
- sepals
- petals
- stamens
- carpels
What are the 5 structures of a flower?
- filament
- anther
- ovary
- style
- stigma
What does the sepal do?
encloses the flower
What does the petals do?
are brightly colored and attracts the pollinators
What do the stamen do?
Produce pollen
What does the carpels do?
Produce ovules
What is a filament?
A stalk in the stamen
What is an anther?
A sac where pollen is produced in the filament in the stamen
What is an ovary?
The base of the carpel that covers the ovules
What is a style?
A structure that leads up to all 4 organs
What is a stigma?
A structure where pollen is received
Difference b/w complete and incomplete flowers?
Flowers has all 4 organs vs Flower is missing one or more organs
Difference between radial and bilateral symmetry?
Imaginary lines in a flower that goes thru the central axis and divides into two equal parts vs a singular imaginary line that divides that flower into two equal parts
What is a fruit?
Angiosperm formed when the ovary wall thickens and matures
What are 3 things to remember about fruit?
- can be fleshy or dry
- can be dispersed via water, wind, or animals
- protects seeds and aid in dispersal
What is the breakdown of the angiosperm life cycle?
- The sporophyte has both male and female gametophytes. Male gametophyte is in the pollen grain while the female gametophyte is in the ovule at base of stigma.
- Most of the flowers have a mechanism that allows for cross-pollination b/w different plants of the same species
- A pollen grain lands on a stigma, germinates it, and the pollen tube of the male gametophyte goes down to the ovary.
- One sperm fertilizes the eggs while the other sperm combines with 2 nuclei in the central cell to initiate the development of food-storing endosperm.
What is double fertilization?
Occurs when the pollen tube discharges two sperms into the female gametophyte within an ovule
What is a micropyle?
Ovule is entered by a pore
What is a cotyledon?
A root and two seeds in the embryo within a seed
When did angiosperm and gymnosperms diverge?
About 305 MYA
How does bilateral symmetry affect angiosperms?
By affecting the movement of pollinators and reducing gene flow in diverging populations
- Gives rise to increased rates of speciation
What is the breakdown of the evolutionary history of angiosperms (4 things)?
- Monocots
- Eudicot
- Basal angiosperms
- Magnoliids
What are some characteristics of Monocots? (6 things)
- Embryos: one cotyledon
- Leaf venation: Veins usually parallel
- Stems: Vascular tissue scattered
- Roots: Root system usually fibrous (no main root)
- Pollen: Pollen grain with one opening
- Flowers: Floral organs usually in multiples of 3
What are some characteristics of eudicots?
- Embryos: two cotyledon
- Leaf venation: Veins usually netlike
- Stems: Vascular tissue arranged in a ring
- Roots: Root system has a main root (taproot)
- Pollen: Pollen grain with 3 opening
- Flowers: Floral organs usually in multiples of4 or 5
What are 3 things to remember about basal angiosperms?
- Amborella trichopoda
- water lilies
- star anise
What are 4 things to remember about magnoliids?
- closely related to monocots and eudicots
- Magnolias
- Laurels
- Black Pepper Plants
What are 4 things to remember about monocots?
- More than 1/4 of angiosperm are monocots
- Orchids
- Grasses
- Palms
What are 3 things to remember about eudicots?
- More than 2/3 of angiosperm are eudicots
- Large legume family
- Rose family
What are seed plants key sources of?
- Food
- Fuel
- Wood products
- medicine
What are the 6 crops that yield 80% of our calories?
- wheat
- rice
- maize
- potatoes
- sweet potatoes
- cassava
What are some threats to plant diversity?
Destruction of habitat leads to a reduction in plant population
which further leads to a reduction of animal species and atmospheric CO2 absorption.
