B1

Question 1

What are plants roles?

Answer 1

All terrestrial life is dependent on plants, they are primary producers, provide us with oxygen, food, raw materials, energy, medicines, recreation. They make up landscapes

Question 2

What are global ecosystems classified into?

Answer 2

Biomes

Question 3

What is biome classification based on?

Answer 3

Plants

Question 4

What do plants consume?

Answer 4

Global consumers of CO2, understanding role of plants in global carbon cycle is essential if we wish to mitigate climate change.

Question 5

What impact had forest fires had?

Answer 5

Result in habitat loss and are exacerbated by climate change.

Question 6

What are plants?

Answer 6

Eukaryotes organisms, contain cells with plasmids, photoautotrophic (carry out photosynthesis), have cells with cell wall outside cell membrane, exhibit great diversity of structure on land.

Question 7

What is plant evolution associated with?

Answer 7

Evolution of structures and physiological strategies to obtain water and minimise water loss. Without compromising the uptake and light dependent assimilation of CO2. At the same time, support and strengthening systems evolved at the anatomical level.

Question 8

What are some key plant adaptations to terrestrial life in higher plants?

Answer 8

Root system - absorption of nutrient and anchorage
Vascular system - plumbing system for the transport of water, minerals, sugars and hormones, made up of xylem and phloem.
Waterproofing covering - cuticle
Stomata - pores through which gases enter and leave the plant by diffusion

Question 9

What do plants cells contain to provide support and strength?

Answer 9

Lignin and cellulose in cell walls. Very tough polymer. This allows plants to reach great heights. Strategic anatomical positioning of lignified cells aids support. Earliest plants may have only been able to stand erect by turgor pressure. Xylem is lignified and performs dual function of water transport and support.

Question 10

What gamete producing structures for plants contain?

Answer 10

Gametangia called antheridia (male) and archegonia (female), which have a protective, sterile jacket of cells. Zygote develops into a multicellular embryo which is retained within the archegonium.

Question 11

What does the embryo develop into?

Answer 11

Multicellular diploid sporophyte generation which produces multicellular sporangia. Sporangia produce spores with walls containing sporopollenin which is one of the most resistant substances known.

Question 12

What are reproductive structures like in plants?

Answer 12

Complex and multicellular, only inner cells become reproductive, outer cells constitute a protective layer and persist after reproductive cells released

Question 13

What do all land plants show?

Answer 13

Heteromorphic alternation of generations. There are two generations ; gametophyte (n) generation and the sporophyte (2n) generation. Both are morphologically and genetically very different.

Question 14

What are bryophytes?

Answer 14

Liverworts, hornworts, mosses. Small plants which are either leafy or thalloid. The earliest terrestrial plants were similar to bryophytes. Modern bryophytes are transitional between charophytes and the vascular plants.

Question 15

What was evolution of extant charophyte algae?

Answer 15

Extant charophyte algae -> extinct early land plants -> extant bryophytes moss.

Question 16

What are leafy and thalloid liverworts?

Answer 16

Leafy and thallose

Question 17

What is marchantia?

Answer 17

Liverwort with a thallose life form

Question 18

What are the leafy mosses? What is dicranium?

Answer 18

Acrocarpous and pleurocarpous. Moss showing leafy life form

Question 19

What environments do bryophytes grow in?

Answer 19

Many situations, usually wet, often dry dessicating environments. Some are aquatic. Dominate certain ecosystems

Question 20

What is bryophytes role in ecosystems?

Answer 20

Primary producers

Question 21

What are bryophytes home to?

Answer 21

Specialised animals e.g. water bears. 16,000 species, mostly mosses (10,000), liverworts (6,000), 100 hornworts. UK has 1,000 species. Uk has 70% of europes brythophytes.

Question 22

What happens in the bryophytes life cycle?

Answer 22

Life cycle exhibits an alternation of 2 distinct generations. Gametophyte and sporophyte. Gametophyte (n), sporophyte (2n). Gametophyte generation is dominant generation. Sporophyte is dependent on gametophyte

Question 23

What happens in the gametophyte generation?

Answer 23

Dominant, haploid generation produces gametangia called antheridia (male) and archegonia (female). If gametophyte is bisexual, then both are produced on the same individual plant. If gametophyte is dioecious, an individual will either be male or female. The antheridia produces lots of haploid, motile sperm. Archegonia produce haploid egg.

Question 24

What happens in the sporophyte generation?

Answer 24

Fertilisation of egg cell (n) by a sperm (n) results in production of a diploid zygote (2n) which develops into a diploid multicellular embryo within the archegonium (on the gametophyte). The embryo grows and differentiates to produce the diploid sporophyte. At maturity, the sporophyte consists of an absorptive foot, a seta and capsule. Inside the capsule, diploid cells undergo meiosis to produce tetras of haploid spores.

Question 25

What is the sporophyte capsule?

Answer 25

At first it has a calyptra derived from the archegonium. The capsule has a lid (operculum) which breaks off to reveal the peristome teeth which regulate the release of the spores by opening and closing in response to humidity. Also presence of stomata

Question 26

Why do sperm require water?

Answer 26

To swim from antheridium to archegonium

Question 27

How do bryophytes absorb nutrients?

Answer 27

Over their whole surface.

Question 28

Why do bryophytes produce rhizoids?

Answer 28

To help anchor the plant and absorb nutrients in abscence of roots.

Question 29

What do mosses not contain?

Answer 29

Xylem and phloem, some mosses have a simple conducting system in their stems.

Question 30

What are sphagnum moss?

Answer 30

Carpet the ground with colour on marshes, heaths, moors. Bog mosses. They play a vital role in the creation of peat bogs, store water in their spongy forms, preventing decay of dead plant material. Eventually from peat. Uk peatlands threatened by habitat loss/drainage for agriculture and forestry.