angiosperms

Question 1

what are angiosperms

Answer 1

flowering plants

Question 2

what do angiosperms contribute to humans

Answer 2

• provide us and our livestock for food
• provide us with raw materials
• used for medicines and other biotech products
• important part of ecology and biodiversity on earth

Question 3

what are some special features of angiosperms

Answer 3

• flowers
• ovules enclosed in carpels
• carpels develop into fruit
• xylem with vessels
• phloem with sieve tube elements
• no antheridia or archegonia

Question 4

what are the different families of angiosperms

Answer 4

1) dicots
2) monocots

Question 5

what are the differences between monocotyledons and dicotyledons

Answer 5

mono
- once cotyledon in seed
- root xyelm and phloem in a ring
- vascular bundles scattered in a stem
- flower parts in threes or fives

dicots
- two cotyledons
root phloem between arms of xyle
vascular bundles in a distinct ring
flowrs in fours or fives

Question 6

give and example of a monocot and a dicot

Answer 6

1) palm trees = monocot
2) oak trees = dicot

Question 7

outline the generalised life cycle of an angiosperm

Answer 7

1) flowers produce stamens (male) and or carpels (females)
2) stamens produce pollen, carpels produce ovules
3) after pollination and fertilisation, seeds are produced in a fruit
4) seeds are dispersed but remain dormant

Question 8

what is the name for grouped flowers

Answer 8

an inflorescence

Question 9

where is each flower formed

Answer 9

a receptacle

Question 10

what do stamens and carpels form

Answer 10

stamens = the androecium
carpels = gynoecium

Question 11

outline the structure of a stamen

Answer 11

the stamen represents the micro sporophylls of the flower
- stamens are made up of a filament and two lobed anther
- each lobe has a pair of microsporangia (pollen sacs)

Question 12

what does each pollen grain consist of

Answer 12

3 cells
- a tube cell
- 2 sperm cells from the generative nucleus

Question 13

outline the structure of a pollen grain

Answer 13

an inner wall called the intine and an outer wall called the exine which is resistant
often packed with startch and oil

Question 14

what is the exine wall made up of

Answer 14

sporopollenin

Question 15

outline the structure of the carpel

Answer 15

represent the megasporophylls
made up of the over, style and stigma and is often compound of up to two + fused carpels

Question 16

what processes occur in the embryo sac of the megagametophyte

Answer 16

a single 2n megaspore mother cell in the nucellus undergoes meiosis producing 4 haploid megaspore cells (of which only one survives)

the surviving megaspore enlarges and the nucleus divides to produce 8 haploid nuclei
- 3 antipodals
- oosphere
- 2 syngergids
- 2 polar bodies which fuse to form a polar nuclei

Question 17

outline pollination in angiosperms

Answer 17

1) pollen reaches the stigma surface where it takes up water and germinates forming a pollen tube
2) the pollen tube grows through the stigma and style to the ovule entering via the micropyle

Question 18

outline fertilisation in angiosperms

Answer 18

1) the generative nucelus divides producing two sperm cells
2) one fuses with the egg cell forming a 2n zygote
3) one fuses with the 2 polar nuclei to form a 3n endosperm

Question 19

what happens to the ovule, ovary, zygote and integument

Answer 19

1) ovule becomes the seed
2) ovary develops into the fruit
3) zygote develops into an embryo which is nourished by the endosperm
4) integument becomes the seed coat

Question 20

outline what is needed for self pollination to occur

Answer 20

• stamens and styles should be near each other in the flower
• flowers must be self compatible
• stamens and styles should develop together or mature together

Question 21

what are the advantages and disadvantages of self pollination

Answer 21

+= pollination is assured
- = inbreeding leading to lower heterozygosity and inbreeding depression

Question 22

outline what is needed for cross pollination

Answer 22

• essential if ourbreeding is to occur
• flower must be self-incompatible
• design must prevent self pollination
• may show specific adaptations to promote transfer of pollen from one flower to another

Question 23

what is protandry

Answer 23

when stamens develop and mature before carpels have a receptive style or stigma

Question 24

what is protogyny

Answer 24

when carpels develop and mature before stamens

Question 25

what is heterostyly

Answer 25

when stamens and styles are at different positions in the flower

Question 26

what is dioecy

Answer 26

the plant is either male or female so doesnt contain both structures

Question 27

what are some pollen transfer methods

Answer 27

1) wind
2) water
3) insects
4) birds
5) bats
6) other animals

Question 28

what traits do insect pollinated flowers have

Answer 28

1) bright colours which can act as guides
2) scents which can be associated with certain flowers
3) rewards for pollinators such as pollen which is high in protein and starch or nectar which is high in sugars
4) mimicry - some plants produce pheramones which mimic the female of a species
5) morphology

Question 29

how are flowers evolved for pollination by birds

Answer 29

• production of large amounts of nectar and floral parts
• have no scent as bird smell is poor
• brightly coloured to attract
• often large and hangining

Question 30

outline how flowers are adapted for wind pollination

Answer 30

• smooth boyant pollen
• dense inflorescences
• stamens exposed
• stigmas exposed with a feathery appearence increasing SA
• lack colour
• no scent

Question 31

what are the two types of fruit

Answer 31

1) dry
2) fleshy

Question 32

what are some ways of fruit and seed dispersal

Answer 32

1) wind
2) water
3) mechanical
4) animals

Question 33

define endozoochory

Answer 33

when animals ingest fruit and seeds which are then excreted, regurgitated or discarded

Question 34

outline coevolution between fruits and animals which are specialised to eat fruit

Answer 34

• large seed
• nutritious
• high qualitiy food
• not available in abundance

Question 35

outline how coevolution between fruits and animals which are not specialsied to eat

Answer 35

• smaller seeds
• carbohydrate rich
• eaten by wide variety of species
• easily found