The tree of Live “Evolves” Kingdoms and Domains The tree of Live “Evolves”

Changes in the classification system New biological understanding lead to a more accurate classification system Genes show important similarities at the molecular level Linnaeu’s didn’t know about DNA DNA from organisms can be sequenced and compared to show evolutionary relationships.

Molecular Clocks DNA comparisons can be used to estimate how long 2 species have been evolving independently. Mutations in the genes accumulate at different rates The more similar mutations 2 species have the closer related they are

Effect on Classification Scientist used to believe there were just 2 groups of living things: plants and animals 2 kingdom system doesn’t adequately represent diversity of life 6 kingdom system: Eubacteria, Archaebacteria, Protista, Fungi, Plantae and Animalia

Eubacteria Prokaryote Cell wall with peptidoglycan (extra outer layer) Unicellular Autotroph or Heterotroph

Archaebacteria Prokaryote Cell wall without peptidoglycan layer Unicellular Autotroph or Heterotroph

Protista Eukaryote Cell walls of cellulose in some Some have chloroplasts Most are unicellular Autotroph or Heterotroph Made up of organisms that cannot be classified elsewhere

Fungi Eukaryote Cell wall of chitin Most are Multicellular (some unicellular) Heterotrophs Feed on dead or decaying matter Secrete digestive enzymes to break down food

Plantae Eukaryote Cell wall of cellulose Chloroplasts Multicellular Autotroph Carry out photosynthesis Non-motile (cannot move from place to place)

Animalia Eukaryote No cell wall Multicellular Heterotroph Most can move (at least at some point in there life cycle) Very diverse group Species that exist in almost every part of the planet

3 Domain System The domain is a more inclusive category than any other Molecular clock analysis allows scientists to group organisms according to how long they have been evolving independently 3 Domains: Bacteria, Archaea, and Eukarya

Bacteria Includes all organisms in the Eubacteria kingdom Unicellular/ Prokaryotes Ecologically diverse Free-living soil organisms Parsites Photosynthetic Anaerobic aerobic

Archaea Includes all organisms in the Archaebacteria kingdom Unicellular/ Prokaryotes Live in the most extreme environments Volcanic hot springs Brine pools Black organic mud (NO oxygen)

Eukarya Includes all organisms in the Protista, Fungi, Plantae and Animalia kingdom ALL organisms have cells with a nucleus (eukaryotes)

Animal Phyla

Porifera Sessile organisms- live their entire adult life attached to a single spot Multicellular, Heterotrophic, No cell walls, Have specialized cells Filter feeders- sift microscopic food particles through the water Produce toxins for protection

Cnidaria Soft-bodied Carnivorous- stinging tentacles Cnidocytes: stinging cells

Cnidaria Radially symmetrical Central mouth surrounded by tentacles Life cycle includes 2 different looking stages

Cnidaria life cycle

Platyhelminthes Flatworms Bilateral symmetry Can be free-living (marine) Most are parasitic (tapeworms) Able to regenerate

Nematoda Round worms Most are free-living Unsegmented worms Can be parasitic Unsegmented worms Depend on diffusion for movement of materials into and out of the body

Annelida Earthworms Leeches Segmented bodies Digestive tract that runs from the mouth to the anus Muscle system that aids in movement

Molluska Clam, Muscle, Squid, Octopus Soft bodied Usually protected by a hard shell Mollusks with out shell: Reduced internal shell: Squid Simple body plan: foot, mantle, shell, visceral mass

Molluska Aquatic mollusks have gills Land mollusks rely on diffusion

Arthropoda Segmented bodies Tough Exoskeleton Jointed appendages

Echinoderm Spiny skin Internal skeleton Water vascular system Suction cuplike structures called tube feet

Echinoderms Sea Urchins Sand dollars Brittle Stars Sea Cucumbers Sea Stars (star fish)

Chordata Dorsal Hallow nerve cord (notochord) Pharyngeal pouches Tail that extends beyond anus Often the tail “disappears” during development