Chapter 27: Diversification of Eukaryotes

Ways Eukaryotic Organisms Have Evolved

nuclear envelope, multicellularity, asexual/sexual reproduction, many organelles, diverse/large/extensive, cytoskeleton.

Protists

All eukaryotes (except land plants, fungi, and animals), typically found in aquatic environments.

Phytophthora Infestans (Water Mold)

caused the Irish Potato Famine

5 Species of Plasmodium

cause Malaria

Protists Ecological Importance

aquatic food chains, primary producers, global carbon cycle

Unikonta

Fungi/Animals

Bikonta

Plants

Earliest Eukaryotes Were Single-Celled Organisms With

flagellum, mitochondria, cytoskeleton, chloroplasts, no cell wall, endomembrane system

Symbiosis

when individuals of two species live in physical contrast

Endosymbiosis

organisms of one species live inside cells of another

Mitochondria

organelles that generate ATP

Endosymbiosis Theory

mitochondria and chloroplasts in eukaryotic cells evolved from free living prokaryotes.

Proof of Endosymbiosis Theory

chloroplasts - have bacteria-like characteristics. Mitochondria - replicate by fission, similar in size to alpha-proteobacteria, have double membranes, have their own genomes

Secondary Endosymbiosis Theory

Eukaryotic cell engulfs a cell that has already undergone primary endosymbiosis

Nuclear Envelope Theory

Nuclear envelope encloses the cell's nucleus, separating it from the cytoplasm regulates nuclear processes and genome organization. Derived from infoldings of the plasma membrane helping endoplasmic reticulum.

Flagellum

Enables movement, hair-like structure, long and found alone or in pairs.

Prokaryotic Flagellum

rotary movement, simple/small

Eukaryotic Flagellum

bending movement, larger/complex

Protist Structures for Support and Protection

Cell walls, hard external shells, rigid structures in plasma membrane. Ex. diatoms.

Multicellularity

Organisms with more than one cell arising independently in a wide array of eukaryotic lineages. Evolved independently at least 25 times in eukaryotes.

Phagocytosis

Ingestion of bacteria or other material by which a cell uses its plasma membrane to engulf a large particle.

Pseudopodia

Protrusion of amoeboid cell for movement/feeding

Absorptive Feeding

Absorbing organic molecules directly from environments

Amoeboid Motion

Movement by changing shape, flagella and cilia

Haploid

Single set of chromosomes

Diploid

2 sets of chromosomes

Gametes

Specialized haploid reproductive cells

Mitosis

produces identical daughter cells

Meiosis

produces genetically different daughter cells

Asexual Reproduction

Eukaryotes - mitosis/cell division. Prokaryotes - fission in bacteria/archaea (always haploid)

Sexual Reproduction

meiosis and fusion of gametes

Alternation of Generations

starts with haploid domination becoming diploid dominated around fertilization step

Amoebozoa

found in freshwater environments. Ex. cellular slime mold, plasmodial slime mold, lobose amoeba

Opisthokonta

fungi, animals, choanoflagellates (protists living as single cells or colonies)

Alveolata

flattened membrane-bound vesicles (alveoli) under plasma membranes, unicellular, emits light. Ex. ciliates, apicomplexans, dinoflagellates