CCEA AS 2 Biology - biodiversity

biodiversity

gives a range of species in a habitat and how evenly balanced the number of individuals are across the species

why is biodiversity not the same as species richness

a habitat can be species rich but not have much biodiversity

Simpson's Index

measure of biodiversity takes into account both the number of species and the number of individuals of each species

Simpson's index equation

D = E ni(ni-1)/N(N-1)

what does ni stand for

total number of organisms of each species

what does N stand for

total number of organisms of all species

what value does D range from

0-1

what does a value of 0 mean

infinite biodiversity

what does a value of 1 mean

no biodiversity

the lower the value of D...

greater the diversity

ecosystem diversity

represents the diversity of ecosystems within the biosphere

biosphere

part of the earth and its atmosphere inhabited by living organisms

habitat

place where organisms live

environment

conditions that affect organisms in a habitat. determines the type of habitat that develops and the species that can live there

abiotic

physical and non living environments

abiotic factors examples

light intensity, temperature, soil conditions

biotic

living environment

biotic examples

food supply, predators, competition

ecosystem

community of organisms interacting with one another and the associated environment

what do ecosystems form

balanced self sufficient ecological unit with its own characteristic pattern of energy flow and nutrient cycle

population

all members of the same species that occur in a particular area at the same time

community

group of species that occur in the same place at the same time

genetic diversity

genetic variability of the species

what factors impact genetic variability

length of existence since it has evolved, degree of directional selection that has taken place in different populations

genetic variability

variation of DNA and genes

when does genetic variability tend to be greater

in species that have become adapted to a wide range of environments, and are subject to higher rates of mutation in DNA

why is it desirable that species are genetically diverse

more subject to directional selection and more likely to remain adapted if environment changes

classification

placing living organisms into groups, not a random process

what is the basic unit of classification

species

what is a species

group of individuals of common ancestry that closely resemble each other and are normally capable of interbreeding to produce fertile offspring

binomial system

gives species two names

what is the first name in the binomial system

generic name indicating the genus to which the species belongs

what is the second name in the binomial system

specific or species name, identifies the species the organism belongs

what to remember when writing the binomial name

first name = capital letter

taxonomy

science or study of all classification

what are groups organised into

hierarchical power

what is each group called

a taxon

taxon groups

1- genus

2- family

3-order

4-class

5-phylum

6-kingdom

genus

group of similar and closely related species

family

group of related genera

order

group of related families

class

group of related orders

phylum

group of related classes

kingdom

group of related phyla

nomenclature

scientific naming of organisms using the binomial system

systematics

placing of organisms into groups based on their similarities and differences

phylogenetic taxonomy

process of the classification of species and larger groups according to their ancestral relations

why is phylogenetic taxonomy more scientific now

due to greater understanding of the evolutionary development of life on earth

what techniques are used to establish phylogeny

morphology and anatomy, cell structure and biochemistry

morphology

external features of an organism

anatomy

internal features of an organism

morphology example similarity

pentadactyl limb = unit in vertebrae's shows that all vertebrae's are related and have common ancestry even though they have evolved

morphology example difference

wings of bats and birds may appear similar but are very different, birds wings have feathers, bats wings are an extension of skin, similar morphologies but different ancestries

cell structure

whether organism is a prokaryote or eukaryote. cells were originally prokaryote but not most are eukaryotic, 4/5 kingdoms have eukaryotic cells

biochemistry

analyses the genomes of species. all basis of life contain carbs, lipids, nucleic acids and proteins

the more similar species are..

more similar DNA,RNA and protein sequences will be

what happens when two or more species evolve from ancestral species

mutations can occur in DNA of one of the species but not always in the other

What are the 3 levels of organisms?

Prokaryotic

Eukaryotic unicellular

Eukaryotic mulitcellular

What are the 5 kingdoms?

Prokaryote, Protoctista, Fungi, Animalia and Plantae

Do prokaryote cells have a nucleus?

No

What are the cell walls of prokaryotes made of?

Peptidoglycans

Are microtubules present in prokaryotes?

No

How do prokaryotes divide?

By fission ( splitting into two without mitosis)

Where is DNA in prokaryote cells?

Free in the cytoplasm

Are protoctistans eukaryotic multicellular or unicellular?

Either if multicellular they have limited differentiation into different tissues

What are protoctistan cell walls made of?

Cellulose or non-cellulose

Some protoctistans have no cell wall - what characteristic do they have?

Motile

Can protoctistans be autotrophic or heterotrophic?

Either

Are fungi multicellular?

Yes but a few unicellular

What are fungi most often organised as?

Hyphae

What are the hyphen cells?

Multinucleate

What are fungal cell walls made of?

Chitin

How do fungi feed?

They are lysotrophs

What is the lysotrophic method of digestion?

The fungi secrete hydrolytic enzymes into the soil by exocytosis and absorb the products of digestion

What do fungi do?

Decompose organic matter

What are carbohydrates and lipids stored as in fungi?

Glycogen and oils

Are plants unicellular?

No - multicellular

How do plants feed?

Autotrophic method of digestion

How do plants store carbohydrates and lipids?

Starch and oils

Are animals multicellular?

Yes

How do animals feed?

They have a heterotrophic method of digestion

Do animals have a cell wall?

No

What is the alternative method of classification?

3 Super Kingdoms or domains

What are the 3 domains?

Archaea, bacteria and eukaryotes