Evolution and biodiversity

taxonomic groups?

kingdom, phylum, class, order, family, genus, species

why do we classify organisms?

• to identify species

• to predict characteristics

• to find evolutionary links

difference between 5 and 6 kingdom system?

5 kingdom system:

• 2 domains: Eukarya and Prokaryota

• 5 kingdoms: Protoctista, Fungi, Plantae, Animalia and Prokaryotae

6 kingdom system:

• 3 domains: Bacteria, Archaea, and Eukarya

• 6 kingdoms: Eubacteria, Archaebacteria, Protoctista, Fungi, Plantae, Animalia

phylogeny

the evolutionary relationships between organisms

advantages of phylogenetic classification

• phylogeny produces a continuous tree whereas classification requires discrete taxonomical groups

• does not imply different groups within the same rank are equivalent

evidence for evolution

• paleontology

• comparative anatomy

• comparative biochemistry

paleontology evidence?

• simple algae and bacteria are in older rocks, whilst vertebrates are in more recent rocks showing that simple life gradually evolves over time

• plant fossils appear before animal fossils showing that animals needed plants to survive in the past

evidence for comparative anatomy?

• presence of homologous structures provides evidence for divergent evolution

evidence for comparative biochemistry?

• the similarities and differences in proteins or molecules such as cytochrome C or rRNA within species

• analaysis of DNA bases can find the common ancestor of two species

homologous structure

a structure that appears superficially different and may perform different functions but has the same underlying structure

divergent evolution

when different species have evolved with a different set of adaptive features from the same common ancestor

analagous structures

when two species have adapted to perform the same function but have a different genetic origin

convergent evolution

when unrelated species begin to share similar traits because they have adapted to similar environments or other selection pressures

interspecific variation

variation between members of different species

intraspecific variation

differences between organisms within a species

causes of genetic variation

• alleles

• mutations

• meiosis

causes of environmental variation

• pH

• sunlight

adaptation

characteristics that increase an organisms chance of survival and reproduction in its environment

types of adaptations

• anatomical

• behavioural

• physiological

types of anatomical adaptations

• body covering

• camouflage

• teeth

• mimicry

types of behavioural adaptations

• survival behaviours

• courtship

• seasonal behaviours

types of physiological adpatations

• poison production

• antibiotic production

natural selection

1. organism within a species show genetic variation by a mutation

2. those with the best characteristics adapted to the selection pressure have increased chance of surviving and therefore successfully reproducing

3. successful organism pass the advantageous allele to their offspring

4. process repeats over many generations with the proportion of individuals with the advantageous allele increasing

5. New species evolved

biodiversity

the variety of living organisms in an area

habitat diversity

the number of different habitats found within an area

species biodiversity

refers to the overall of species richness and species evenness

genetic biodiversity

the variety of genes that make up a species

species richness

the number of different species living in a particular area

species evenness

a comparison of the numbers of individuals of each species living in a community

factors that affect genetic biodiversity

• mutations

• interbreeding (gene flow)

ways genetic biodiversity can decrease?

• selective breeding

• captive breeding

• artificial cloning

• genetic bottlenecks

• founder effect

• genetic drift

genetic bottlenecks

when few individuals survive an event or change

founder effect

when a small number of individuals create a new colony that is geographically isolated from the original

genetic drift

when the frequency of occurence of a particular allele is reduced

factors affecting biodiversity

• deforestation

• agriculture

• human population growth

• climate change

aesthetic reasons to maintain biodiversity

• presence of different plants and animals enriches our lives

• the natural world provides inspiration to poets, musicians and writers

economic reasons to maintain biodiversity

• promotes tourism

• allows for certain industries to continue growing e.g hardwood timber

ecological reasons to maintain biodiversity

• organisms are interdependent

• keystone species maintain the structure of an ecological community

what is in situ conservation?

conservation taking place within an organism’s natural habitat

what is ex situ conservation?

conservation taking place out of the natural habitat

examples of in situ conservation

• marine conservation zones

• wildlife reserves

examples of ex situ conservation

• seed banks

• botanic gardens

• zoos

IUCN

publishes the Red List which helps countries to work together to then conserve the species

Rio Convention

• CBD - requires countries to develop national strategies for sustainable development

• UNFCCC - nations take steps to stabilise greenhouse gas concentrations in the atmosphere

• UNCCD - prevents the transformation of fertile land into desert

Countryside Stewardship Scheme (environmental now)

• sustaining the beauty and diversity of the landscape

• improving, extending and creating wildlife habitats