the recovery of the black robin from near extinction is an internationally renowned conservation...
TRANSCRIPT
DO NOW Exam 2006
The recovery of the black robin from near extinction is an internationally renowned conservation success story
In 1980 there were only 5 black robins in NZ, with just a single breeding pair left. Today the population is over 250. This has caused changes in the black robin gene pool.
a) Define the term gene poolb) Discuss how this near-extinction affected the
gene pool of the black robin and why it is still classified as endangered
Homework
Explain how enzymes function as catalysts
Enzyme activity may be affected by › Temperature› pH› Co-factor/co-enzymes› InhibitorsDiscuss how enzyme activity is affected by these factors
DO NOW Exam 2004
Describe the structure of the cell membrane. You may use labelled diagrams in your answer
Discuss the importance of the cell membrane in maintaining a constant internal environment for the cell
Do NOW
Name two organelles that plants have that animals do not and their function
Define founder effect
Plant DiversityMAH – Year 12 Biology
What you need to know...
How three taxonomic groups of plants reproduce
Compare and contrast the three types
Describe how the plants are adapted for their environment in relation to reproduction
Kingdom Plantae
Plant reproduction
Vegetative reproduction (asexual)› Low metabolic cost to the plant› Allows efficient exploitation of the resources in the
environment› Does not promote genetic diversity› Environmental change and pathogens present risks
Sexual reproduction:› Promotes genetic diversity in a population› Involves the alternation of generations› High metabolic cost to the plant› Allows species survival in changing environment
REPRODUCTION
…is the biological process by which new individual organisms are produced. Genes are passed on to the next generation, which ensures continuation of the species
Alternation of Generations
Variation in plants exists from sexual reproduction› INVOLVES AN ALTERNATION OF
GENERATIONS
Involves a haploid stage (n) called gametophyte (gamete producing plant)
Involves a diploid stage (2n) called a sporophyte (spore-producing plant)
Alternation of generations
Sexual reproduction occurs in all types of plants Involves the “alternation of generations”
Definitions:› Sporophyte = diploid or 2n stage, produces spores
by meiosis› Gametophyte = haploid or n stage, produces
gametes by mitosis› Spore = haploid structure that develops directly
into an organism (the gametophyte)› Gamete = haploid structure that fuses through
fertilisation to produce a diploid zygote (the sporophyte)
that develop directly into an organism (the gametophyte)
fuses through fertilisation to produce a diploid zygote
Alternation of generations
To do: Stick in the handout and fill in the words
Explain in your own words what is happening
A Spore – some definitions…
A minute, typically one-celled, reproductive unit capable of giving rise to a new individual without sexual fusion, characteristic of lower plants, fungi, and protozoans
(in a plant exhibiting alternation of generations) A haploid reproductive cell that gives rise to a gametophyte
Kingdom Plantae1. Bryophytes Mosses, liverworts and hornworts.
moss
liverwort
hornwort
moss
The Bryophytes
Bryophytes
Lack water gathering roots and specialised vascular tissues for transport
Usually less than 15cm in height but may sprawl over a considerable area
Absorb moisture and minerals through above ground structures via diffusion and therefore grow in moist environments
They do not have roots as such however they are anchored to the substrate they grow in by rhizoids
They have small leaf like structures however they lack the specialised tissues of the true leaf and are only one to a few cells thick.
The body of the plant is designed for storage and support
Bryophyte reproduction
The gametophyte phase dominates
Gametes are produced by mitosis in structures called the antheridium (male) and archegonium (female)
Bi-flagellate sperm are released by the antheridium that swim to the archegonium in the process of fertilisation [No water = No reproduction]
The zygote develops into a sporophyte phase that is often totally dependent on the gametophyte for nutrition
The sporophyte consists of a foot, stalk and single sporangium that produces and spreads spores by meiosis
Bryophyte reproduction
Bryophyte reproduction – bi-flagellate sperm
To watch...
DO NOW
What is the name of the structure that produces sperm on the male gametophyte of mosses?
Describe two ways in which bryophytes are dependent on liquid water
If you looked at the chromosome numbers of what looked like a complete small moss plant, which part would be diploid and which part haploid?
Structures and functions - Bryophytes
Structure Function
Bi-flagellate sperm Allows sperm to swim from antheridium to archegonium to achieve fertilisation
Sporangia of sporophyte raised into the air
Archegonia produce chemical signals for sperm
Sporangia explosively discharge spores
Sporophyte grows on the gametophyte
Structure Function
Bi-flagellate sperm Allows sperm to swim from antheridium to archegonium to achieve fertilisation
Sporangia of sporophyte raised into the air
Ensures efficient dispersal of spores
Archegonia produce chemical signals for sperm
Allows sperm to home in on the correct location for fertilisation
Sporangia explosively discharge spores
Ensures efficient dispersal of spores
Sporophyte grows on the gametophyte
Sporophyte does not need to be independent or photosynthesise
TO DO
In groups of 3 › Use the play dough to ‘model’ the
bryophyte life cycle› You will need to be able to explain it to
another group Include the structures etc..
DO NOW
What is a bryophyte?
Define gametophyte and sporophyte?
What is the cytoplasm?
Plant Group 2 – the Ferns
Ferns are vascular plants that can grow much larger than bryophytes
Presence of vascular system allows internal transport of water and food
Leaves (fronds) are made up of leaflets (pinnae), efficiently capturing light, ferns are often found in lower levels of a forest
Leaves are composed of a variety of different cell types
The Ferns
Reproduction
Spores give rise to bisexual gametophytes. The spores develop into a flat membranous type
structure with rhizoids. The antheridia and archegonia grow on the underside.
The gametophyte contains both the male and female parts (The male part = the antheridia and the female part = archegonia). (ie male and female parts on the same gametophyte)
The antheridia and archegonia mature at different times ensuring cross fertilisation.
Flagellated sperm are produced by the antheridia and therefore requiring water for fertilisation
Fertilisation occurs in the archegonia and development of the sporophyte also occurs here.
Initially the sporophyte receives nutrients form the gametophyte however, it soon becomes photosynthetically independent.
Once the sporophyte is independent, the gametophyte disintegrates
Copy diagram from Board
Diagram also pg. 298 (Bayley) Once finished you will need to collect a
rearrange sentences sheet from Mrs H
Then draw a table that outlines similarities and differences between the reproduction of moss and ferns
Similarities and Differences between fern and moss
Similar Different
Require moist environmentWater for fertilisation has to be present
Ferns more complexGrow larger - Have vascular tissues
Rhizoids present Bryophytes: Sporophyte is dependent on gametophyte for nutrientsGametophyte is dominant stage
Alternation of generationsSpores are produced
Ferns: Sporophyte not dependent on gametophyte Sporophyte is the dominant stage
Separate male and female gametophytes
Dioecious refers to a plant population having separate male and female plants.
Monoecious, an individual that has both male and female reproductive units on the same plant;
Angiosperms
What are they? Flower Structure Male and Female Gametes Reproductive cycle
Plant group 3 – The Angiosperms
Angiosperms (flowering plants) are the most abundant and successful plant group
300,000 different species counted so far
Vascular plants with a wide range of sizes, adaptations and habitats
Angiosperms
Angiosperms are the final improvement on plant reproduction;
They grow their seeds inside an ovary;
The ovary is embedded inside a flower;
After fertilisation the flower falls away and the ovary swells to become a fruit.
Reproduction and Development
Flowers
Angiosperm sporophytes produce unique reproductive structures called flowers
Flowers consist of four types of highly modified leaves› Sepals› Petals› Stamen› Pistil (or carpel)
Their site of attachment to the stem is the receptacle
Reproduction and Development
Flower Structure
Flower Structure
Flower Structure
Wind Pollinated Flowers
Copy diagram on the board and reasons for the changes
Reproduction and Development
Flower Anatomy
Sepals and petals are nonreproductive organs› Sepals – protect the other three, the floral
bud› Petals – attract pollinators and act as
“landing pads”
Reproduction and Development
Flower Anatomy
Anthers and carpels are male and female reproductive organs, respectively› Anther – consists of filament (long, thin) and
anther (pollen)› Carpel – consists of stigma (sticky opening),
style (long tube connecting stigma to ovary), ovary (houses ovules; becomes fruit), and ovules (develops female gametes; become seeds)
› COPY DIAGRAMS ON BOARD
Reproduction and Development
Flower Anatomy
Complete flowers – have all four floral organs› Ex: Trillium
Incomplete flowers – missing one or more of the four floral organs
Reproduction and Development
Flower Anatomy
Bisexual flower (perfect flower) is equipped with both stamens and carpals› All complete and many incomplete flowers
are bisexual A unisexual flower is missing either
stamens (carpellate flower) or carpels (staminate flower)
Reproduction and Development
Unisexual Flowers
Monoecious plants: staminate and carpellate flowers at separate locations on the same individual plant› Ex: corn ears derived from clusters of
carpellate flowers; tassels consist of staminate flowers
Reproduction and Development
Unisexual Flowers
Dioecious plants: staminate and carpellate flowers on separate plants› Ex: Date palms and Sagittaria (below) have
carpellate individuals that produce dates and staminate individuals that produce pollen
Diagram on board of angiosperm reproduction
Video
http://www.youtube.com/watch?v=bUjVHUf4d1I
Diagram on board of angiosperm reproduction
Need more help?
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Angiosperm.html
Angiosperm reproduction
Sporophyte generation dominates Reproduction is independent of water Reproduction requires pollen transfer to
the stigma, usually by wind or animal pollinators
Reproduction involves a “double fertilisation”
Reproduction is made more effective by using seeds to distribute embryonic plants
Gametophyte generation reduced to small number of cells that are dependent on the sporophyte
Pollination can be done by...
Pollination can be done by...
Insects Birds Snails Wasps Bats Wind
Self vs cross pollination
Seed dispersal (page 258)
Seed dispersal occurs by:› Wind (e.g. dandelion, sycamore)› Water› Animals (e.g. succulent fruit, hooked fruit)› Explosive methods (e.g. legumes)
Complete the exercises on page 258, Biozone
Pollination
Pollination is the transfer of pollen from the anther to the stigma, usually by wind or animals
Use pages 292-294 to answer these questions:› What are the major differences between wind and
animal pollinated flowers?› How do flowering plants ensure they do not self
fertilise?› What is the difference between pollination and
fertilisation?› Describe the events between pollination and
fertilisation, what has to happen? What is the “double fertilisation?”
Seed formation and fruit (pages 294-297)
The new sporophyte in angiosperms is packaged into a seed for dispersal
Use pages 294-297 to answer these questions:› What is a fruit? What part of the flower develops into the
fruit and the seed?› What is the difference between a monocotyledon seed and a
dicotyledon seed?› Draw a labelled diagram of a typical seed, along with the
labels and their functions› What are the main mechanisms for dispersing seeds?› What are the factors required for seed germination?› What advantage do angiosperms have over mosses and
ferns by producing fruit and seeds?
Germination
Germination requires the following factors:
› Oxygen› Water› Correct temperature
Germination involves re-starting the metabolism of the seed
Photosynthesis only occurs when chlorophyll is produced in new leaves in the emerging shoot
Comparing the different plants
Prepare a table comparing mosses, ferns and angiosperms for the following features:› Dominant generation› Which generation is dependent on the other› Requirements for water in reproduction› Environments that the plant can live in› Methods to avoid self-fertilisation
Prepare simple diagrams, with labels, showing the reproductive cycles of the three plant groups
Begin linking structures and functions to the plant and its lifestyle that can be used in an essay question