Wednesday, 15 March 2017

Vascular Plants

Vascular Plants (Phylum Tracheophyta)

  • Tracheids - Specialised cells for conducting water and supporting tissues (forming the xylem vessels)
  • All SPOROPHYTES in this group are larger than the gametophytes and have ROOTS, STEMS AND LEAVES.
  • can be further sub divided into the non- sees tracheophytes and the seed plants

THE SPERMATOPHYTA 'Seed Plants';


Now represented by two Phyla:

- The Gymnosperms:
 ( Cycads, Gingkos, Gneetophytes, Confiers)

- Angiosperms
 (Magnoliphyta or flowering plants)

COMMON THINGS IN ALL SEED PLANTS;

  • Seeds
  • Reduced Gametophytes
  • Heterospory: Spored of two different sizes and sexes
  • Ovules: Female gametophyte, protected by tissues of sporangium
  • Pollen: Male Gametes (Sperm cells)

THE ALTERNATION OF GERNERATION IN THE SPERMATOPHYTA;


 
  • The gametophyte generation is reduced to a very small, simple stage (only a few cells!).
  • The gametophyte develops partly or entirely whilst it is still nutritionally dependent on the sporophyte. 

Non Vascular Plants

Non Vascular Plants (Non- Tracheophytes): Bryophytes 

Main Features; 

  • The group are largely confined to damp conditions which allow the passage of sperm to the archegonia and the flow of nutrients to individual’s cells. 

  • Non- Vascular plants have recently been divided into 3 phyla which are started below (Originally one Bryophyte) and are classified according to the shape and the growth pattern of the sporophyte 

  • They DON’T PRODUCE SEEDS due to them nurturing their zygotes in the tissues of the parent plant.

  • They rely on the surface film of water to act as a transport system as tracheophytes are not huge plants therefore do not develop a transport system, so film of water transports all the nutrients which enters by diffusions. Some can tolerate very dry conditions but still relay on a moisture film for growth and reproduction.
Examples of Non vascular plants



Bryophyte (Mosses)


Formerly Class: Bryopside (musci)

First Fossil to date back 415 Mya.
Ø  Differentiated into simple leaf- like structures that can form stems

Ø  Some species with cells called hydroids which ‘die’ and become tubes through which water can pass- first origins of transport systems.

Ø  There are not lignified* but are otherwise analogous to xylem in the vascular plants.

Sporophyte is stalked with a spore capsule 


Hepatophyta (Liverworts)

Formerly class: Hepaticopsida
Thought to have been the first to evolve.
Ø  Some are leafy and prostrate, other are plate-like.

Ø  Sporophyte is not stalked (Although gametophyte which bears it may be)

Ø  Rhiziods (‘Rootlike structures’) are unicellular filaments

Anthocerophyta (Hornworts)

Formerly class: Anthocertopsida

Ø  Gametophytes always thalliod (not differenced into steam or leaf)

Ø  Sporophyte* stalked with needle like capsule- capable of indefinite growth.

Ø  Process stomata and form mutualistic relationship with cyanobacteria*

Form some of the largest non-tracheophytes- up to 20cm 


*SPOROPHYTE; is the diploid multicellular stage in the life cycle of a plant or alga. It develops from the zygote produced when a haploid egg cell is fertilized by a haploid sperm and each sporophyte cell therefore has a double set of chromosomes, one set from each parent.

*CYANOBACTERIA:  bacteria but are capable of photosynthesis. 

*LIGNIGIED: make rigid and woody by the deposition of lignin in cell walls.




LIFE CYCLE

Life Cycle Haploid/ Diploid Stage; Alternation of the generations between haploid gamete- producing Gametophyte and diploid spore-producing sporophytes, the gametophytes being the more prominent of the two

Life cycle of Non Vascular plants from Life, the science of biology


Sporophytes attached to the, and derive nourishment from, the gametophytes.
-          Male gametes (Mobile) are produced in an ANTHERIDUM
-          Female gametes are produced in an ARCHEGONIUM
Ø  The male swims in a surface film of a water and fertilise the female egg in situ. After syngamy, the sporophyte grows out of the gametophyte and derives its moistures and nutrients from it.
Remaining attached to the gametophyte throughout its life




Domain Plante (Basics)

Definition; 

‘A multicellular, Photosynthetic, eukaryotic organism (includes some algae)…which includes develops from the embryos protected by tissues of the parent plant” (all land plants)

THE LAND PLANTS; 

10 major clades;
  •           Three clades have no system of conducting fluids- calling the Non- Vascular Plants or Non Tracheophytes

  •           Seven Clades have well- developed fluid transport systems based on cells called TRACHEIDS/ TRACHEOPHYTES

Divided into:



       Non-vascular plants
       Vascular land plants:
                - Non-seed plants
                - Seed plants:
                                >Gymnosperms
                                > Angiosperms

Domain Protista

The Kingdom Protista are a ‘paraphyletic’ group!

(Paraphyletic = consists of all the descendants of the last common ancestor of the group's members)

 

The Basics;

Mobile or stationary
 Most are unicellular, some multicellular
Autotrophs or heterotrophs, or both.
 
 
A mobile Protista


Both ASEXUAL and SEXUAL reproduction
Simple plasma membrane or stiffer structure (cell wall, internal shell)
Many contain endosymbionts

CHARACTERISTICS;

  • Moist habitats
  • Many single celled, some clonal, some multicellular (or colonial)
  • Some mobile, other stationary
  • Important in nitrogen cycling and in various carbon and nitrogen cycles
  • Some important human parasites and pathogens

 

GROUPING;

Often grouped by ecological role;
  1. Algae
  2. Protozoa
  3. Fungus- like

CLASSIFICATION BY BROAD 'SUPERGROUPS'

Excavata
Archaeplastida
Euglenozoa
Rhizaria
Stramenopila
Amoebozoa
Alveolata
Opisthokonta
Chromalveolata etc.

Movement;

Attached to surfaces and mobile;
Free-floating species sometimes grouped together as the plankton

  • Ciliates: ciliated, move using cilia
  •  Flagellates: flagellated, move using flagella
  • Amoeboid: amoebae, move using pseudo-podia
  • Slide, using carbohydrate or protein slime
 

Chlorophyta

Is one of the largest groups of green algae. Most aquatic, some terrestrial.

Pediastrum boryanum

Domain: Eukaryota

Kingdom:
Protista

Division:
Chlorophyta

Class:
Chlorophyceae

Order:
Chlorococcales

Family:
Hydrodictyaceae

Genus:
Pediastrum

Species: 
Pediastrum boryanum




Origin of different morphologies and multicellular bodies.....
Pediastrum boryanum

The Eukayotic Cell

Under Eukaryotic cell comes the Animal cell and Plant cell, and in comparison to the size the prokaryotic cell, the eukaryotic cell is much larger.


ANIMAL CELL

An animal cell and plant cell does have much more in common then in difference.

Typical Features;

Animal cell with the added chloplasts which is only in plants



 

MITOCHONDRIA;
the organelle that provides energy for the entire cell, by extracting from food during oxidative metabolism.

NUCLEUS;
command centre of the cell where DNA is located

ENDOPLASMIC RETICULUM;
smooth and rough;
Smooth - System of internal membranes that aids; manufacture of carbohydrates and lipids
Rough - Internal membranes studded with ribosomes that carry out proteins synthesis

GOLGI BODY;
collects, packages and distributes molecules manufactures molecules in the cell

(PLASMA) MEMBRANE;
Lipid bilayer in which proteins are embedded

RIBOSOMES;
Some complexes of RNA and Proteins that are sites synthesis

CHLOROPLAST;
is only found in the plant cell. This is on the diagram to show the difference in the animal and plant cells, chloroplast helps the plant cell produce food as it attaches it from the sun enabling photosynthesis.



PLANT CELL




As above you have the chloroplast which looks like this;
Heterotrophs capture light energy to produce their own food., Animal and bacterial cells contain chlorophyll, but it is not bound within organelles., Animal cells are able to capture light energy through stromal lamellae.




The only difference between a plant cell and an animal is;

  1. Vacuole
  2. Chloroplast (stated above)
  3. Cell wall

VACUOLE;
 A membrane-bound organelle in the cytoplasm of most cells, especially plant cells, containing water and dissolved substances such as salts, sugars, enzymes, and amino acids.

CELL WALL;
a multi-layered structure unique to plants.
uses for this;
Strength to support the plant
Rigidity to fix cell shape
Flexibility
Porosity
Water-proofing
Barrier to pests
Protection against environmental stress 
Apoplastic transport
Signalling and sensing 


Cross section of both animal and plant cell to compare both

The prokaryotic Cell

Species definition;
"population of cells with similar characteristics"

Cell wall;
- Peptidoglycan
- Outer membrane

The DNA of Bacteria is contained in a circular chromosome, folded into many loops

Bacteria have both a plasma membrane and cell wall

Bacteria often have a small circles of additional DNA called plasmids.

SHARED CHARACTERISTICS

  1. Plasma or cell membrane
  2. Nucleoid
  3. Cytoplasm; Cytosol + Insoluble Particles
  4. Ribosomes

DISTINCTIVE CHARACTERISTICS

  1. Cell walls
  2. Capsules
  3. Internal membranes
  4. Flagella
  5. Pili
  6. Fimbriae
  7. Cytoskeleton

PLASMA MEMBRANE;
is a selective barrier enclosing the cell that separates the interior and exterior of the cell from the environment. It is semi permeable, it allows gases, nutrients and waste in and out of the cell. (Bilayer of Phospholipids with proteins attached to or embedded in it)

NUCLEIOD;
The region in the prokaryotic cell where DNA is located

CYTOPLASM;
Composed of cytosol; mostly water and soluble particles

RIBOSOMES;
complex of RNA and proteins which function as sites for proteins synthesis (RNA-PROTIENS)

CELL WALL;
Outside the plasma membrane, bacteria contains peptidoglycan that covers the entire cell:
- gives rigidity
- Support and shape

CAPSULE;
layer of polysaccharides enclosing the cell wall.
protects the bacteria from the immune function and desiccation, also helps attachment

INTERNAL MEMBRANE;
A system of folded bilayer membrane that contains molecules needed for;
- Photosynthesis
- Cell division
- energy releasing reactions

FLAGELLA;
Corkscrew- like appendage used for movement.
composed of flagellin and protein ring structures anchored in plasma membrane forming a rotor

PILI;
Hair like structure, shorter then flagella.
Made of protein projecting from the surface of many bacteria
Used for adherence.

FIMBRIAE;
Shorter then the pili.
Used for adherence to animal cells, food and protection

CYTOSKELETON;
Network of filaments structures, extends length of cell.
Inside the plasma membrane. present in rod shape Bactria (E.Coli)

The Domains

Correct me if I am wrong.... but there are 3 main domains in the 'tree of life'

  1. Eukaya
  2. Archea
  3. Bactria
As stated above this are the main 3 domains... lets go into a bit more depth.

DOMAIN EUKAYA;
This domain contains 4 more domains within it;
  1. Protista
  2. Fungi
  3. Plante
  4. Animalia
DOMAIN ARCHEA;

These are only found in the most EXTREME ENVIRONMENTS:

·         Hot springs

·         Anerobic or microaerophilic conditions

·         Sulphurous Volcanic upwellings

·         Extremely saline conditions

·         High alkalinity

·         Extremely acidic conditions
 
Phylum: EURYARCHAEOTA
·         Metgangens
·         Obligate anaerobes producing methane
·         Some are also extreme thermophiles
·         Extreme Halophiles
·         Some use Bacteriorhodopsin to photosynthesis
 
Methanobrevibacter smithii
Domain: Archaea
Kingdom: Euryarchaeota
Phylum: Euryarcheota
Class: Methanobacteria
Order: Methanobacteriales
Family: Methanobacteriaceae
Genus: Methanobrevibacter
Species: M. smithii
 
Phylum: Crenarchaeota

-          Extreme acidophilic and/or thermophiles (often found at volcanic vents)

-          E.g Thermus aquaticus= taq polymerase used DNA amplification

-          Some can survive pH 0.9 and >70 degrees


Sulfolobus acidocaldarius

Domain: Archaea
Kingdom: Crenarchaeota
Phylum: Crenarchaeota
Class: Thermoprotei
Order: Sulfolobales
Family: Sulfolobaceae
Genus: Sulfolobus
Species: Sulfolobus acidocaldarius
 
DOMAIN BACTERIA;


Phylum: Proteobacteria

·         Gram negative

-          Negatively charged cell wall:

       Helps evading Phagocytosis

       Physical Barrier

·         Largest Number of species:

-          E.coli, salmonella, vibrio, Helicobacter

-          Anaerobic, Chemoautotrophs, photoautotrophs, heterotrophs

-          Beneficial symbionts

-          Pathogens

Example;

ESCHERICHA COLI (E.COLI)

Domain: Bacteria
Phylum: Eubacteria
Class: Protebacteria
Order: Gammaprotebacteria
Family: Enterobacteriace
Genus: Escherichia
Species: E.Coli


Phylum: Firmicutes

·         Gram positive, with cell wall containing teichoid acids

·         Teichoid acids:

-          Movement of cations in/out of the cell

-          Antigenic specificity

-          Some produce extremely persistent endospore e.g. anthrax, tetanus

·         Actinomycetales are filamentous bacteria

·         Superficially resembling fungi

·         Important component of the soil microbiota

·         Some serious pathogen, e.g. Mycobacterium

·         Produce many antibiotics, e.g. Streptomycin group

STAPHYLOCOCCUS ALBUS (S.ALBUS)

Domain: Bacteria
Phylum: Firmicutes
Class: Cocci
Order: Bacillales
Family: Staphylococcaceae
Genus: Staphylococcus
Species: Staphylococcus Albus

Why is The Hardy Weinberg Equilibrum Important

The Hardy- Weinberg Equilibrium principle is very important to the scientific genetic society as;

  • It is the foundation of which almost all the theory of population genetic of sexually- reproducing organisms is based

  • It is a NULL MODEL

  • Deviations give evidence of selection, Genetic drift, gene flow, mutation or non random mating in a population
 
ASSUMPTIONS AND VIOLATIONS OF THE HARDY WEINBERG EQUILIBRUM
 
  • All individuals have equal probabilities of surviving and reproducing. Violated if NATURAL SELECTION (differential reproductive success) occurs
 
  • The population is infinitely large. Violated by GENETIC DRIFT
 
 
  • Genes are not added to or removed from the population by migration. Violated by GENE FLOW
 
 
  • There is no MUTATION
 
 
  • Mating is random. Violated e.g. by INBREEDING AND SEXUAL SELECTION
 
 
 
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The Dutch Biologist (Tinbergen) Questions' on Animal Behaviour

Animal Behaviour is how animals learn, communicate with one another, form social groups and choose mates.
In each case, animal behaviour can be considered at the individual level; individual behaviour is determined in part by a complex interplay of the nervous and endocrine systems.
Behaviour is also influenced by environment (Will explain Later)
  • Finally Behaviour like all traits are shaped by natural selection! 

Tinbergen was a Dutch Biologist that set out 4 questions to determine Animal Behaviour

TINBERGEN'S QUESTIONS
 
 
  • CAUSATION; what physiological mechanisms cause the behaviour? (Multiple Answers)
Example: A Bird sings causes hormones levels to have changed in response to changes in the day length OR Air passing through specialized singing organs.
 
  • DEVELOPMENT; how did the behaviour develop?
 
Here the focus is on the role of the genes and the environment in shaping behaviour, In birds typically the male its the learning of the song that the child will learn from its father.
 
  • ADAPTIVE FUNCTION; how does the behaviour promote the individuals ability to survive and reproduce?
The male Bird sings in order to attract a mate and then reproduce
 
  • EVOLUTIONARY HISTORY; how did the behaviour evolve over time?
Complex bird songs may have evolved from vocalizations made by ancestors that were reinforced and became increasing stereotyped and ritualized
 
 
 
The Answers to Tinbergen's questions rely on an interplay between genes and the environment.
 
the influence of genes is especially clear in innate behaviour, those that our instinctive (Ducks lining up, Turtle that are just born making there way to the sea)
 
 
A particular behaviour may also depend on an individual experience, for example fruit flies learn to avoid certain areas/ locations or substances if they associate them with unpleasant experiences
 
 
 
 
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The Hardy- Weinberg Equilibrum

For a 2 allele situation the Hardy- Weinberg Equilibrium is the best to use......

REMEMBER THIS...

p2 + 2pq + q2 = 1
 
P and Q are the frequencies of the alleles A and a
 
 
p2 + 2pq + q2 = 1
(AA)  +  (Aa)  +  (aa) = 1
 
 
At the Equilibrium, allele frequency does not change over time
 
 
EXAMPLE;
 
A particular species of fish is rarely seen, however we can find eggs and sperm in the water
(these are haploid = 1)  
 
  • The dominant allele 'R' codes for red scale colour
  • The recessive allele 'r' codes for white scale colour
80% where 0.8 had  Dominate 'R'
20% where 0.2 had recessive 'r'
 
RR (p2)- 0.8 x 0.8 = 0.64
Rr (pq)- 0.8 x 0.2 = 0.16
rR (pq)- 0.2 x 0.8 = 0.16
rr (q2) - 0.2 x 0.2 = 0.04
 
add all the numbers together the total should = 1




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Important Words in Genetics

The Most Important Words in Genetics and their definitions

FITNESS;
is the ability of an individual to survive and reproduce relative to conspecifics

ADAPTATIONS;
are traits that increase the fitness of an individual relative to individuals that lack the traits

PHENOTYPE;
the physical expression of the organisms' genes

CHARACTERS;
the features of the phenotype (eye colour)

TRAIT;
the specific form of a character heritable (brown, blue, green eyes)

GENOTYPES;
the genetic constitution of an individual

ALLELE;
Different forms of (Variants) of a gene

LOCUS;
A gene in a chromosome

GENE POOL;
Sum of all copies of all alleles at all loci in a population (A1, A2, A3 ,A4)


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Past Paper example

DESCRIBE THE MAIN BEHAVIOURAL ADAPTATIONS FOR CONSEVING HEAT IN MAMMALS.
Adaptations help organisms survive in their habitats or ecological Niche, adaptations can be behavioural or physiological.
 Behavioural adaptations can be inherited or learnt and include tool use, language and swarming behaviour. for example Heat tolerant animals and adaptations for survival in hot places. Many animals try to avoid the heat by hiding away during the hottest parts of the day in burrows and dens. Others have physical adaptations that help body heat dissipate, such as large ears. To avoid being scorched.
but animals that are Cold tolerant  have evolved various methods for coping with very low temperatures. Some animals hibernate, take shelter, or even migrate to warmer areas. Others, such as Antarctic seals, have warm fur and a thick layer of blubber for insulation. where as Arctic foxes have short noses, legs, and ears. But has a big furry tail to wrap around them to isolate them during the icy storms at night. They only hunt during they day to avoid the harsh winter night
      • HOW MIGHT A MARINE MAMMAL BALANCE IT'S CELLULAR OSMOLARITY WITH IT'S ENVIRONMENT?
      Marine Animals are osmoconformers their body fluids are similar to seawater in osmolalrity, so they gain and lose water at equal rates and have no need to expend energy expelling water or salt from the body. However, if they are placed in water more or less concentrated than seawater, their tissues shrink or swell, their organelles and cell membranes are damaged, and they die

      DESCRIBE THE RESPIRATORY PATHWAYS WHICH MIGHT BE EMPOLYED DURING THE FIRST FIVE MINUTES OF MODERATE EXERCISE CARRIED OUT BY AN ATHLETE?

       Nutrients are built upon an understanding of how nutrients such as carbohydrate, fat, and protein contribute to the fuel supply needed by the body to perform exercise. These nutrients get converted to energy in the form of Adenosine Triphosphate or ATP.

      It is from the energy released by the breakdown of ATP that allows muscle cells to contract. However, each nutrient has unique properties that determine how it gets converted to ATP. for example carbohydrates is the main nutrient that fuels exercise of a moderate to high intensity, while fat can fuel low intensity exercise for long periods of time. Proteins are generally used to maintain and repair body tissues, - not normally a power source


      • WHAT ARE THE RELATIVE COSTS AND BENEFITS OF ENDOTHERMY?
      An endotherm is an organism which maintains its body at a metabolically favourable temperature, largely by the use of heat set free by its internal bodily functions instead of relying almost purely on ambient heat.
      therefore....
      1. Endothermic animals can inhabit areas that are too cold for ectothermic animals. They also have the ability to be active even when it is cold. 

       2. Ectothermic animals need far less food. As much as 80% of the food energy acquired by an endothermic animal is used just to keep warm

      • HOW DO ENVIRONMENTAL TEMPERATURE CHANGES AFFECT CELLULAR RESPIRATION IN AN ECTOTHERM?
      An Ectotherm are so called cold blooded animals that rely on external sources such as sunlight or rock faces to heat up there internal bodies. Therefore Environmental temperature is vital to Ectotherms,  if the environment temperature lowers cellular respiration could be affected due to the enzyme structures within the body being affected meaning growth, breathing, sexual interaction, are all depleting slowly.

      • HOW MIGHT AN ECTOTHERM RESPOND TO THESE CHANGES?
      Ectotherms will respond quickly to these changes and find shade to equal there temperature to what it should be or if it needs to be higher they will find sun and bask in it to increase the temperature.

      • WHAT ARE THE MAIN FACTORS AFFECTING THE EFFICIENCY OF GAS DIFFUSION FROM THE LUNG TO THE TISSUES OF AN ANIMAL?
      Temperature (Viscosity of medium)
      Area over which exchange occur
      Concentration gradient
      Distance over which Substance diffuse









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      EXPANDING MY BLOG

      Hey, Science lovers and Readers

      This is a personal message. I am now expanding my blogs to social media.



       TWITTER. if you have twitter follow me on @Science_nerd101 you can ask me question or have a chat, it would be lovely!

      I have finally created the account, got it up and running! it will get better over time.


      I will be posting the recent blogs up there so you can keep up and also the occasional fact and just the reminder of what definitions mean etc....


      
      
      @Science_nerd101

      Negative and Positive Feedback Loops

      Negative Feedback

      Negative feedback is an important type of control that is found in homeostasis. A negative feedback control system responds when conditions change from the ideal or set point and returns conditions to this set point.

      Direction of compensation is opposite to direction of disturbance.





      To regulate these things the body needs firstly to detect the level then to respond in an appropriate way.

       For temperature, water and glucose there is a level called the 'norm' (e.g, normal body temperature is 36.9°C).
      If the level gets too high this triggers the body to lower it. If the level gets too low this triggers the body to raise it. This is the principle of negative feedback.



      Examples;
      • Control of Blood pressure
      • Blood Sugar concentration
      • Heat response
      • Cold Response

      Positive Feedback

      Compensation INCREASES the level of disturbance = amplified response.
      Positive feedback is when a high level of something triggers the body to increase it even further

      Neuron Membrane depolarization: A typical positive feedback response

      - Emptying of body cavities (defecation, urination, birth, ejaculation)
      - Filing of Body cavities
      - Sexual Behaviour
      - Muscle

      Feedforward

      Feedforward information serves to alter the set point in regulatory systems. An examples might be changes in set point due to acclimation.



      SOME SYSTEMS NEED BOTH POSITIVE AND NEGATIVE FEEDBACK RESPONSES


      for example the Human Ovarian and Uterine Cycles
      the cycle that women go through,  systems within the body are constantly changing meaning the maintaining levels of Estragon are having to keep changing, therefore both responses are needed


      Overall....
      All control Systems require:
      A sensor
      A reaction mechanism (integrator and effector)
      Communication system (E.g. hormones)



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