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