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Yr 1 Sem 1 > Biodiversity (plants) > Flashcards

Biodiversity (plants) Flashcards

1
Q

Define being alive

A

Need to capture resources from environment, grow + reproduce yourself

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2
Q

Which kingdoms are contained within Eukarya?

A

Protista, Chromista, Plantae, Fungi, Animalia

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3
Q

LUCA

A

Last universal common ancestor
- possesses characteristics shared by all living organisms today
- has DNA, RNA, proteins, cell mem., systems for capturing light energy, carbs + enzymes

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4
Q

2nd law of thermodynamics

A

Total entropy of isolated system can only increase over time (order->disorder) so life uses energy to maintain + reproduce itself in orderly fashion

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5
Q

Stanley miller experiment

A

1953 heating cooling mimicked conditions Earths est. 4 billion years ago.
Methane, hydrogen, ammonium -> organic matter (glycine produced)
so simple chemicals need energy to form complex structures

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6
Q

Chemotrophs

A

Harness energy from chemicals (use ATP), reactions all exothermic

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7
Q

Peter Mitchell Nobel prize 1978

A

Chemiosmotic hypothesis - energy harnessed by ETC + used for H+ pump to set up pH conc. gradient so h+ diffuse through F type ATPase
feature of LUCA + found in Archaea +Bacteria
- needs oxidants + reductants

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8
Q

Archaean photosynthesis

A

Bacteriorhodopsin (retinal) has red colour + used to store photons (energy), cis-trans isomerisation driven by light moves 2H per photon

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9
Q

Bacterial photosynthesis

A

Uses chlorophyll, has photosynthetic reaction centres which absorb light resulting in e transfer along ETC

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10
Q

What are the two types of bacterial reaction centres?

A

Fe-S (found in green sulphur bacteria + heliobacteria)
Fe (cytochrome) can bind to H2S (found in purple sulphur + green non-sulphur bacteria)

*cyanobacteria only bacteria to have both types of reaction centres

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11
Q

How did oxygen evolving complex form?

A

Lateral gene transfer -> reaction centres combined + began to work together
allowed oxidation of water

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12
Q

Evidence for oxygen production in cyanobacteria

A

Fossils - stromatolites formed by growth of microbial mats w/ bands of iron oxides
Oxidation of metals -> O2 in atmosphere
Huronian Ice age after oxygen, as CO2 formed + is weaker than methane (CH4)

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13
Q

Pros and cons of oxygen

A

Pros - ozone layer forms preventing UV reaching surface allowing life outside of water

Cons - superoxide (free unpaired e), hydrogen peroxide (reactive, used in bleach, hydroxyl radical (very reactive) - Fenton reaction

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14
Q

Phagocytosis (1st heterotrophs)

A

aerobic respiration more efficient so allows cells to evolve + engulf smaller ones

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15
Q

When did complex structures appear in eukaryotes?

A

2 billion yrs ago, from Archaea
- Lokiarchaeota possess traits of eukaryotes including phagocytosis

Mitochondria + chloroplasts result of single endosymbiotic event
archaea consumed aerobic proteobacterium + cyanobacterium

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16
Q

Sexual reproduction green alga (Chlamydomonas reinhardtii)

A

Haploid most of the time, mitosis gives 4 daughter cells, reproduce sexually when stressed
Two types of gametophytes (mt+ and mt-)
Forms persistent zygospore - diploid, inactive

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17
Q

First land plants (pros and cons)

A

Coincided w/ increased O2, followed Cambrian explosion
Pros - new spaces, higher pCO2
Cons - lack of water, no current to aid reproduction

18
Q

Give examples of bryophytes

A

Liverworts - dominant gametophyte, rhizoids grow down + absorb water, sperm swim form male to female gametophores so sporophyte grows on gametophore

Stomata + vascular tissue in mosses + hornworts

Moss - more complex leaf structure , simple water conducting tissues, ombotrophic (absorbs nutrients from water), sporophyte grows well above gametophyte

Hornworts - presence of cyanobacteria in clefts, symbiosis w/ nitrogen fixer

19
Q

Problems with bryophyte

A

Poor ability to capture + retain water, poor water transport + limited uptake of nutrients, limited height so needs to be near surface

19
Q

Rhynie Chert

A

410 Mya, fossils studied by Lang
preserved fossils of different species
features include vascular bundles, mycorrhizal associations (symbiotic relationship)

20
Q

Lycopodiophyta

A

inc. spike moss, quillwort, clubmoss (not mosses)
-> reproduce by spores, alternation of generations, sporophyte dominant + photosynthetic
*increasing development of larger more dominant sporophyte

21
Q

Tracheids

A

Type of water conducting cell in xylem, found in vascular plants
1’ growth cell division at tip - cell elongation
2’ growth cell division at cambia, structures become thicker eg. lycophytes evolved thick stems w/ lignin

22
Q

Carboniferous forests

A

360-300 Mya formation of Pangaea extensive lycopod forests
Changing atmosphere as CO2 levels dropped
led to rise of megaphylls (leafy plants)

23
Q

Horsetail innovations

A

Ring of xylem - better water transport + branching
Extensive roots (rhizomes) - better water uptake, vegetative spread, deciduous
Reproductive structures - strobili cone like structure produces spores

24
Q

Ferns (pteridophyta)

A

Have rhizomes + vascular tissues, megaphylls
During reproduction, archegonium contains egg and antheridium encapsulates sperms

25
Q

Progymnosperms e.g Archaeopteris

A

reproduce by spores/gametophytes like ferns but has ring of vascular cambium - wood

26
Q

What caused fall of lycopods

A

Replaced by gymnosperms (naked seed) in the Permian due to new drying climate w/ Pangea formation opposed to warm wet tropical carboniferous

27
Q

How do cones and seeds work?

A

Cones - seed matures in female cone + pollen released from male cone, controlled seed release leads to embryo
Seed- nucellus from mother feeds embryo + protected by seed coat

28
Q

Cycads

A

1st dominant gymnosperms, dioicous, drought tolerant, slow wood production

29
Q

Ginkgophyta

A

Dioecious, deciduous, fleshy seed wall, branching

29
Q

Pinophyta (conifers)

A

often monoecious, single extant order (pinales), long lived, grow fast + big, woody branched trees

30
Q

Gnetophyta

A

3 families v. different to one another, share feature w/ flowering plants

31
Q

Angiosperms

A

cased seeds protected by ovary, endosperm acts as storage tissue that feeds embryo, flowers innovated, capable of double fertilisation

have xylem which are wider but prone to embolisms

male + female organs found together

32
Q

Most primitive angiosperm

A

Amborella - has flowers but no vessels (only tracheids), dioecious, females have staminodes (infertile stamens)

33
Q

Evolution of fruit

A

resistant seeds tolerate gut environment so are spread + germinate w/ fertiliser, not exclusively angiosperm but mainly

34
Q

3 plants that have developed different methods to reach canopy?

A

Epiphytes, climbers, hemiparasites (root into stem of host + connect to xylem)

35
Q

Plants with short life span

A

Ruderals - weed species (short-lived) that exploit gaps in ecosystem/disturbance e.g. poppies

Ephemerals - annual/perennial, grow following rain, persist as seeds or bulbs/roots

36
Q

Adaptation to manage low water in deserts

A

Biochemical convergence - CAM photosynthesis prevents water loss by closing stomata during day

37
Q

What are cotyledons?

A

‘seed leaves’ produced in embryo w/ different structure to actual leaves
angiosperms - monocots, dicots

38
Q

Key fungi features

A

Hyphae - tubular filaments divided by septae into separate cells, cell walls contain chitin, growth from tips

Mycelium - mass of hyphae, denser mycelium forms mushrooms, large SA:V increases absorption

39
Q

Saprotrophs

A

secreted enzymes decompose dead organic material

40
Q

Mutualism-parasitism continuum

A

Fungi are both:
Mutualists - arbuscules exchange phosphate for assimilated carbon at root cell plasma membranes
Parasites - hyphae grow into hosts + manipulate to yield more nutrients (biotrophs) or kill it and live off of remains (necrotrophs)

Yr 1 Sem 1 (3 decks)

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