TOPIC 4: BIODIVERSITY AND NATURAL RESOURCES

Define 'Species'

Organisms with similar morphology, physiology and behaviour that are able to interbreed together to produce fertile offspring.

They are reproductively isolated from other species.

Define 'Habitat'

Where an organism lives.

Each habitat has a particular set of conditions that supports a distinctive combination of organisms.

Within a habitat there may be many populations of an organism.

Define 'Population'

A group of interbreeding individuals of the same species found within an area

The various populations of a habitat make up a community

Define 'Community'

Various species living in a common location

Define 'Niche'

The role of a species within its habitat. This refers to the way an organism exploits its environment. This is unique to each species

If 2 species in a habitat have the same niche what happens?

The 2 species will compete with each other. The better adapted organism will outcompete the other and exclude it from the habitat.

What is the Competitive Exclusion Principle?

2 species competing for the same limiting resource cannot coexist.

What is an adaptation?

The way an organism is specialised in its features ie anatomy, physiology, behaviour to suit their and environment and allow them to uniquely exploit their particular niches and survive to reproduce.

Define 'Behavioural Adaptation'

How an animal acts/behaves to survive and reproduce

Define 'Physiological Adaptation'

Features of the internal mechanisms of an organism that helps them to survive ie. their biochemistry, enzymes

Define 'Anatomical Adaptations'

Physical adaptations in an organisms structure

Define 'Coadaptation'

When 2 species undergo adaptation together and become closely adapted as they are dependent on eachother

Define 'Natural Selection'

a process by which species of animals and plants that are best adapted to their environment survive and reproduce, while those that are less well adapted die out.

Outline the process of natural selection.

1) A population has genetic variation with new alleles created due to mutations

2) A change in the environment causes a change in selection pressures amongst the population.

3) An allele that was selectively neutral now becomes advantageous

4) Organisms with this advantageous allele are more likely to survive to adulthood, reproduce and produce offspring

5) Their offspring is more likely to have the allele and it becomes more common in the population. The allele frequency increases.

Define 'Selection Pressures'

External influences which affect an organisms ability to survive in the environment - they may make certain alleles advantageous and others not

Define ' Selectively Neutral Allele'

An allele which has no particular advantage or disadvantage

Define 'Evolution'

A change in allele frequency in a population over time/generations

Define 'Directional Selection'

A type of natural selection where the population trait distribution shifts from one end of the extreme to the other due to selection pressures.

ie. giraffes had short necks but couldn't reach leaves in trees. as a result the distribution of neck lengths shifted to favour giraffes with long heads.

Define 'Stabilising Selection'

A type of natural selection where selection pressures act against the 2 extremes of a trait.

ie. if a plant is too short it can't compete with other plants for sunlight but if it's too tall it is more susceptible to damage. Therefore the advantageous allele would be for medium height

Define ' Disruptive Selection'

A type of natural selection where selection pressures act against individuals in the middle of the trait distribution.

What 3 things does the ability of a population to adapt to new conditions depend on?

1) The strength of the selection pressure
2) The size of the gene pool
3) The reproductive rate of the organism

Define Speciation

A process where populations evolve to become distinct species

Outline the process of Speciation.

The population becomes isolated.

The population, now split into 2 groups, will become less similar as they respond to the different selection pressures of their environment.

Eventually the difference becomes so large that they are now reproductively isolated and can't breed to make fertile offspring.

Define Geographic Isolation

When a population becomes physically separated ie. by a mountain or an earthquake

Define Temporal Isolation

Isolation due to time differences ie. different mating times

Define 'Mechanical Isolation'

Isolation reproductive sex organs are incompatible in terms of size or location.

Define 'Behavioural Isolation'

Isolation due to differences in behaviour ie. mating behaviour

Define 'Gametic Isolation'

Isolation as gametes are incomplete.

Define 'Endemic Species'

Species that are specific to a location / Species that is restricted in it's distribution

Define 'Inbreeding Depression'

The reduced biological fitness of a population as a result of inbreeding between closely related individuals

Define 'Genetic Drift'

Variation in frequency of alleles over generations due to sampling errors.
ie. loss of alleles due to inbreeding

What does the 'P' represent in the Hardy-Weinberg Equation?

The dominant allele

What does the 'Q' represent in the Hardy-Weinberg Equation

The recessive allele

Define 'Gene Pool'

All of the alleles of all the genes in a population

What does the Hardy Weinberg Equation help us calculate?

Allele Frequencies

What are the 2 equations in the Hardy Weinberg Equation?

P + Q = 1

P² + 2PQ + Q² = 1

What does P² represent in the Hardy Weinberg Equation?

The frequency of homozygous dominant indivudals

What does 2PQ represent in the Hardy Weinberg Equation?

The frequency of heterozygous individuals

What does Q² represent in the Hardy Weinberg Equations?

The frequency of homozygous recessive individuals

What 5 conditions are needed for the Hardy Weinberg Equation to work?

A population that is large enough for genetic drift not to occur

No mutations

Random mating with respect to genotype

No natural selection

No immigration or emigration

What is the role of the golgi apparatus in a plant cell?

To package and modify proteins

What is the role of the amyloplast in a plant cell?

It contains starch grains.
It converts starch into sugar when the plant needs energy

What is the role of the cell wall in a plant cell?

Helps maintain shape and protects cells.

What is the role of the cell surface membrane in a plant cell?

Controls the movement of substances in and out of a cell

What is the role of the mitochondrian in a plant cell?

Produces ATP and is the site of aerobic respiration

What is the role of the nuclear envelope in a plant cell?

A double lipid bilayer with pores to allow things to move in and out of the nucleus

What is the role of the nucleolus in a plant cell?

Makes ribosomes

What is the role of chromatin in the plant cell?

A mass of genetic material composed of DNA and proteins which condense to form chromosomes during mitosis.
It is made up of histones and DNA and has the primary purpose of compressing DNA into a compact unit

What is the role of the rough endoplasmic reticulum in a plant cell?

Has ribosomes on it.
Site of translation during protein synthesis

What is the role of the plasmodesmata (sing. plasmodesma) in a plant cell?

A channel of cytoplasm that passes through the cell walls of adjacent plant cells and allows communication between them

What is the pit and what is the role of the pit in a plant cell?

Thin portions of the cell wall where the secondary wall is interrupted, exposing the underlying primary cell wall.
allows adjacent cells to communicate and exchange fluids

What is the role of the middle lamella in a plant cell?

A layer of calcium pectate which cements the cell walls of adjacent cells together

What is the role of the smooth endoplasmic reticulum in a plant cell?

Involved in the creation and storage of lipids and steroids

What is the role of the tonoplast in a plant cell?

The tonoplast aka the vacuolar membrane separate vacuolar contents from the cytoplasm

What is the role of the vacuole in a plant cell?

Contributes to the rigidity of the plants. It store nutrients and waste (which is then releases)

What is the role of the chloroplast in a plant cell?

Contains chlorophyll which uses the energy of the sun to convert CO2 and H20 to Glucose and O2

What is the role of the ribosome in a plant cell?

The site of translation within photosynthesis

What is the role of the cytoplasm in a plant cell?

The liquid that fills a cell made out of mostly salt and water.
It helps a cell keep its shape
Important enzymes may also be kept here

Do plant cells have centrioles?

No

In the binomial system of classification what is the first part of the name? What does it mean? How is it written?

Genus.
It is shared by all closely related species.
Is written in italics with a capital letter

In the binomial system of classification what does the second part of the name mean? How is it written?

It defines the particular species in the genus
It is written in italics and doesn't have a capital letter

What is a dichotomous key?

A tool that aids in the classification of an unknown organism by offering 2 alternatives at each stage to determine the identity of the organism

Define 'Classification'

Organising the variety of life based on relationships between organism using differences and similarities in the phenotypes and genotyprs of organism

Define 'Taxanomic Hierarchy' and give an example of one.

A series of categories in biological classification in successive levels of decreasing or increasing order - introduced by Linnaeus. Organisms are placed in groups based on them having similar characteristics

It is made up of a series of taxa

Define 'Taxa'

A group within biological classification

What is the taxonomic rank (in order)

Phyllum

Class

Order

Family

Genus

Species

please can oranges find good seeds

How many kingdoms are there?

5

Define 'Heterotroph'

Organisms that are unable to synthesise organic materials from inorganic sources and hence feeds on organic matter from other organisms

Define 'Autotroph'

An organism that is able to make organic material from inorganic sources
ie. via photosynthesis

Define 'Kingdom Animalia'

Multicellular eukaryotes that are heterotrophs

Define 'Kingdom Plantae'

Multicellular eukaryotes which are autotrophs

Define 'Kingdom Fungi'

(not always multicellular) eukaryotes which are heterotrophs
They absorb nutrient from decaying matter after external digestion and the cell wall is made up of chitin

Define 'Kingdom Protoctista'

Eukaryotes that photosynthesise or feed on organic matter from other sources but aren't included in other kingdoms.

Can be multicellular or unicellular

Define 'Kingdom Prokaryote'

Prokaryote organisms ie. bacteria

What further kingdom has been introduced?

Kingdom Chromista

Define 'Molecular Phylogeny'

Using molecular similarities and differences in DNA/RNA sequences and amino acids in proteins to show evolutionary relationships

What is suggested by organisms having similar/shared characteristics?

They may share a common ancestor or have an evolutionary link

What did Carl Woese find when trying to define the evolutionary relationships of prokaryotes using molecular phylogeny?

A group of 'bacteria' which lacked sequences characteristic of bacteria + had no peptidoglycans in their walls and had differing membrane lipids from eukaryotes and other bacteria.

He proposed these 'bacteria' belonged to a new category called 'archaea' which were distinct from both the bacteria and the eukaryote

Are archaea more closely related to bacteria or eukaryotes?

Eukaryotes

due to their lack of peptidoglycan in their walls + a similar number of protein molecules in RNA polymerase than bacteria

How do the scientific community evaluate and communicate ideas? 3

Peer review: evaluation of scientific work by others working in the same field. They carefully check the data and the interpretations of it. May repeat experiment to confirm/validate findings

Scientific Journals / Magazines + Conferences/Presentations

Media/ Newspapers/Internet

Define 'Genetic Diversity'

The different types of alleles in the genet pool of a species

Where is the vascular bundle found?

The stem of a plant

Write the components of the vascular bundle from innermost to outermost?

Xylem, Phloem Sieve Tubes, Sclerenchyma fibres

What is the role of xylem vessels? 3

Transport of water + inorganic ions

They play a role in transpiration.

Their stiffened cell wall helps support the plant.

Define 'Transpiration'

The process where moisture is carried through plants from the roots to stomata on the underside of leaves where it evaporates from

What is the role of phloem sieve tubes?

They form long tubes for transport of products of photosynthesis (ie. glucose in the form of sucrose and amino acids)

They do not play a role in supporting the plant

They are involved in translocation

Define 'Translocation'

The movement of sucrose and amino acids produced from photosynthesis from leaves to other tissues (ie source to sink) throughout the plant.

T/F: Sclerenchyma have a chisel shaped end of fibre

True

T/F: Sclerenchyma have transport functions in the plant

False!

Sclerenchyma do not have a transport function in the plant

T/F: Sclerenchyma have lignin in them and support the plant

True.
They have lignin in them meaning they are hollow fibres made up of dead cels that support the plant

Why is nitrogen an important mineral in plants?

It is an essential component of amino acids which make up proteins + important in chlorophyll

Is Nitrogen mobile in the plant? If so what does this mean?

Nitrogen is mobile in the plant meaning it can be moved from older tissues to newer tissues in a plant.

This means signs of mineral deficiencies are first seen in older leaves

What are signs of nitrogen deficiency?

stunted growth, chlorosis and a purple stem

Define 'Chlorosis'

When plants leaves produced insufficient chlorophyll - turning them yellow

Why is calcium an important nutrient in plants?

It is a component of calcium pectate in the middle lamella that sticks adjacent plant cell walls together + regulates transport of other nutrients in the plant + is involved in the activation of certain enzymes

Is calcium mobile in the plant? What does this mean for the plant?

Calcium is immobile in the plant. This means if there's a deficiency in one tissue the tissue is unable to remobilise itself using nutrients from older tissues.

This means calcium deficiency is first seen in newer leaves

What are the sign of calcium deficiency?

Rolling/downward curling of new leaves
Necrotic (dead) areas developed at tips and edges of leaves
Stunted growth

Why is magnesium an important mineral for plants?

Important for chlorophyll production

What is chlorophyll?

A green pigment in plants that is critical in photosynthesis to allow plants to absorb energy from sunlight

What is an enzyme co-factor?

Non-protein molecules that aid enzymes in the catalysis of reactions