Growth & Development

How and why may an organism change over it’s lifespan?

Animals often exhibit metamorphosis in their development.

Can you explain at least one advantage to this “strategy”?

GROWTH & DEVELOPMENT

• GROWTH – the increase in size of an organism

Surface to volume ratio limits how large a cell can grow

Growth in Single-Celled Organisms

In single-celled organisms growth occurs by an increase in cell size

Cell can either stay big or divide

Growth in Multi-celled Organisms

In multi-celled organisms growth occurs by production of new cells

· Increases the total number of cells in the organism

· Increases total surface to volume ratio

Living OrganismsAre capable of :-• Growth and

development• Metabolism• Homeostatis• Movement

1. Detect and react to stimuli

2. Reproduction3. Composed of cells4. Contain DNA5. Adaptation and

evolution

All Species Inventory

• in 2001– international project launched to identify and

record every species on Earth in the next 25 years

– a very challenging undertaking considering that to date 1.5 million organisms have been named

– it is estimated that anywhere from 7 – 100 million living species exist

• science of organizing organisms into groups– those with similar properties being grouped

together– similarities are due to relatedness• phylogeny is the study of evolutionary history of

organisms– organization of organisms reflect phylogeny or

evolutionary relationships

Taxonomy• three separate but interrelated disciplines

are involved in taxonomy– identification• characterizing organisms

– classification• arranging into similar groups

– nomenclature• naming organisms

Prokaryote Classification

• technologies used to characterize and ID prokaryotes– microscopic examination– culture characteristics– biochemical testing– nucleic acid analysis– combination of the

above is most accurate

Taxonomic Classification Categories• arranged in hierarchical order• species is basic unit

DomainKingdom

Phylum or DivisionClassOrderFamilyGenus

Species

Classification Systems: a short history

• In, Carl Linnaeus devised the first classification system, placing plants and animals in separate systems– Linnaeus placed all microorganism in

one genus he named Chaos