Topic 4-Biodiversity and Natural Resources

Why do individuals of the same species vary?

Due to different alleles

What is genetic diversity?

Variety of alleles in the gene pool of a species or population.

What is the gene pool?

The complete set of alleles in a species.

What are two things you can look at to measure genetic diversity?

Phenotype and genotype

What do different alleles codes for?

Slightly different versions of the same characteristics

The larger number of phenotypes…

The greater the genetic diversity

How can the genotype be tested?

Samples of an organisms DNA can be taken and the sequence of base pairs analysed

What can you tell by sequencing the DNA of individuals of the same species?

You can see similarities and differences in the alleles within a species

What can you measure using the genotype of see genetic diversity?

The number of different alleles a species has for one characteristic

What does the heterozygosity index measure?

Genetic diversity

What does a higher heterozygosity index mean in a population?

There’s is greater genetic diversity

What is the equation for the heterozygosity index?

H=number of heterozygotes/number of individuals in the population

What is the equation for the index of diversity?

N=Total number of organisms of all species

n=Total number of organisms of one species

Sum of

What does biodiversity mean?

The variety of living organisms in an area

What is species diversity?

The number of different species and the abundance of each species in an area

What does genetic diversity mean?

The variation of alleles within a species or a population of a species

What does endemism mean?

When a species is unique to a single place

What 3 things has natural selection lead to?

-adaptation

-evolution

-increased biodiversity

What reduces species diversity?

Human activity

What helps maintain biodiversity?

Conservation

What does habitat mean?

The place an organism lives

Describe how to measure species diversity in terms of counting the number of different species in an area.

1. Count the number of different species in an area

2. This is the species richness

3. The higher the number of species the greater the species richness

What does species richness not show?

Abundance of each species

Describe how to measure species diversity in terms of also counting the number of individuals in each species.

1. Count the number of different species and the number of individuals in each species

2. Use an index of diversity to calculate species diversity

Describe the method for sampling species diversity.

1. Choose a small area within the species to sample

2. The sample should be random to avoid bias-you can use a random number generator to get coordinates for a box in the grid

3. Count the number of individuals of each species in the sample area

   -Plants= quadrat

   -Flying insects=sweepnet

   -Ground insects=pitfall trap

   -Aquatic animals=net

4. Repeat

5. Use the results to estimate the total number of individuals or the species richness in the habitat

6. When comparing habitats use the same sampling technique

What does niche mean?

The role of a species which in its habitat

What 2 groups does a niche interact with?

-living organisms

-non living environment

How many species can occupy the same niche?

1

What may happen if 2 species have the same niche?

One will always outcompete the other

What are adaptations?

Features that increase an organisms chance of survival

What are behavioural adaptations and what is one example?

-ways an organism acts that increases its chance of survival

-possums play dead to escape attack

What are physiological adaptations And what is an example of this?

-processes inside and organisms body that increase its chance of survival

-some bacteria produce antibiotics to kill other bacteria and reduce competition

What are anatomical adaptations and what is an example for this?

-structural features of an organism that increases its chance of survival

-otters have a streamlines shape making it easy to glide through the water and catch prey

Describe how evolution occurs by natural selection.

1. Every population has variation due to random mutations

2. Some variations make individuals more likely to survive

3. Selection pressures (predators, disease, competition, climate change)

4. The better adapted individuals have a selective advantage and are more likely to survive, reproduce and pass on their beneficial alleles

5. Over many generations the proportion of individuals with the advantageous allele increases and the species has evolved to adapt to its surroundings

How does evolution occur?

By natural selection

What does allele frequency mean?

How often an allele occurs in a population

What are new alleles generated by?

Mutations

What does the hardy-Weinberg principle predict?

That allele frequencies won’t change

What are the conditions needed to calculate the hardy-Weinberg principle?

-large population

-no immigration

-no emigration

-no mutations

-no natural selection

-random mating

What is the hardy-Weinberg equation that predicts allele frequency and what does each letter represent?

p+q=1

-p=frequency of the dominant allele

-q=frequency of the recessive allele

What is the hardy-Weinberg equation that predicts genotype and phenotype and what does such part mean?

p²+2pq+q²=1

-p²=frequency of the homozygous dominant genotype

-2pq=frequency of the heterozygous genotype

-q²=frequency of the homozygous recessive genotype

When does geographical isolation happen?

When a physical barrier divides a population of a species.

What may cause geographical isolation?

-Floods

-volcanic eruptions

-earthquakes

What may happen because the environment is different on each side of the barrier?

Different characteristics become more common due to natural selection because there are different selection pressures

Describe how the phenotype changes due to geographical isolation?

-different characteristics will be more advantageous on each side, allele frequency will change in each population

-mutations will take place independently in each population, also changing allele frequencies

-leading to changes in phenotype frequencies

What will each of the geographically isolated groups not be able to do as they become more genetically distinct?

They won’t be able to breed to produce fertile offspring-they’re reproductively isolated

What is taxonomy?

Science of classification

What does taxonomy involve?

Naming organisms and organising them into groups based on similarities and differences

How many taxonomic groups are there?

8

What are the groups organisms are put into?

-Domain

-Kingdom

-Phylum

-Class

-Order

-Family

-Genus

-Species

How are species named?

By using their genus and species in a binomial wording system

Why are species given a specific name?

-to minimise confusion

What is the classification of organisms based on?

Phenotypes and genotypes

-looking at DNA sequence

Describe the features of the prokaryotae kingdom and an example for it

-bacteria

-prokayotes, unicellular, no nucleus

Describe the features of the protoctista kingdom and an example for it

-algae

-eukaryotic cells, live in water, single celled/simple organisms

Describe the features of the fungi kingdom and give an example for it

-Yeasts

-eukaryotic, chitin cell wall, saprotrophic

Describe the features of the plantae kingdom and give an example for it

-moss

-eukaryotic, multicellular, cellulose cell walls, photosynthesise

Describe the features of the animalia kingdom and give an example for this

-mammals

-eukaryotic, multicellular, no cell wall

What is phylogeny?

The study of the evolutionary history of groups of organisms

What does phylogeny tell you?

Which species are related to which and how closely related they are

What does molecular phylogeny look at?

DNA and proteins to see how closely related organisms are

What are the 3 domains?

Archaea, Bacteria, Eukaryota

Describe the cell wall and its function

-rigid structure that surrounds plant cells

-made of cellulose

-supports plant cells

Describe the middle lamella and its function

-outermost layer of the cell

-acts as an adhesive p, sticks adjacent plant cells together

-provides stability

Describe the plasmodesmata and its function

-channels in the cell walls that link adjacent cells together

-allows transport of substances and communication between cells

Describe the pits and its function

-wall is very thin

-they’re arranged in pairs

-allows transport of substances between cells

Describe the chloroplast and its function

-small, flattened structure

-surrounded by a double membrane

-contains thylakoid membranes which are stacked to form grana

-grana are linked together by lamella- thin flat pieces of thylakoid membrane

-site of photosynthesis

Describe the amyloplast and its function

-small organelle enclosed by a membrane

-contain starch granules

-store starch grains and convert starch back to glucose

Describe the vacuole and tonoplast and its function

-vacuole is a compartment surrounded by a membrane called the tonoplast

-vacuole contains cell sap which keeps the cells turgid

-involved in the break down and isolation of unwanted chemicals in the cell

-tonoplast controls what enters and leaves the vacuole

How do plants store excess glucose?

As starch

What two polysaccharides of alpha glucose does starch contain?

-amylose and amylopectin

Describe amylose

-long unbranched chain of alpha glucose

-glycosidic bonds give it a coiled structure

-compact so it’s good for storage

Describe amylopectin

-long branched chain of alpha glucose

-side chains allow easy breakdown of glycosidic bonds

-glucose can be released quickly

Why doesn’t Starchaffect osmosis?

It’s insoluble

Describe the structure and formation of cellulose

-long unbranched chains of beta glucose

-joined by 1-4 glycosidic bonds where one cellulose monosaccharide is rotated by 180 degrees

-straight chain

-condensation reaction

What do the string threads in cellulose provide?

Structural support

Why are cellulose microfibrils in the cell wall strong?

-contains cellulose in a net like arrangement

-strength of microfibrils and their arrangement in the cell wall gives plant fibres strength

-cellulose embedded in a matrix

-hydrogen bonds hold cellulose chains together

-which prevents cellulose from sliding over each other.

What is the function of xylem cells?

Transports water and minerals up the plant and provides support

Describe the structure of xylem cells

• Long, tube like structures made of dead cells

• Found in bundles

• Cells are longer and they have a hollow lumen with no cytoplasm and end walls

• Walls are thickened with lumen to support the plant

• Water and mineral ions move into and out of the vessels through pits in the walls where there is no lignin

What is the function of the scleremchyma?

Provide support

Describe the structure of the sclerenchyma

-made of bundles of dead cells that run vertically

-cells are longer and have hollow lumen and have end walls

-walls thickness by lignin but dont contain pits

-have more cellulose than other plants

What is the function of the phoenix tissue?

Transports organic solutes like sugars from where they’re made in the plant to where they’re needed.

Translocation

What diffrent types of cells does phloem tissue include?

Sieve tube elements and companion cells

What are sieve tube elements?

Living cells and are joined end to end to form sieve tubes

What do the sieve tubes allow?

For solutes to pass through

What is unusual about sieve tube elements?

They have no nucleas, a very thin layer of cytoplasm and few organelles.

Cytoplasm of adjacent cells is connected through the holes in the sieve plates.

What does the lack of nucleas and other organelles in sieve tube elements mean?

They can’t survive on their own, so it has a companion cell

What do companion cells do?

Carty out the living functions fir both themselves and their sieve cells.

What do xylem vessels and phloem tissue group together to form?

Vascular bundles

What does sustainability mean?

Using resources in a way that meets the needs of the present generation without messing it up for future generations

What are renewable resources?

Resources that can be used indefinitely without running out

How is making products from plant fibres more sustainable?

Less fossil fuel is used up and crops can be regrown to maintain the supply for future generations

Other than being sustainable what are products made from plant fibres also?

They’re biodegradable-they can be broken down by microbes

What is easier to do to plants than oils?

Easier to grow and process, making them cheaper and is easier to do in developing countries as less technology and expertise is used

Where is starch found?

All plants

What are plastics made from plant based materials called?

Bioplastics

Why is making plastics from starch more sustainable?

Less fossil fuel is used up and the crops which the starch came from can be regrown

What can vehicle fuel also be made from?

Starch-bioethanol

How are water and inorganic ions absorbed by plants?

Through the roots and travel through the plant in the xylem

Why do plants need water?

-photosynthesis

-to transport minerals

-to maintain structural rigidity

-to regulate temperature