Origin and diversification of eukaryotes Flashcards
What major groups are included in Eukarya?
Protists, plants, animals, fungi
What distinguishes eukarya from prokarya
They have a nucleus and membrane-enclosed organelles.
Are eukaryotes or prokaryotes more complex?
Eukaryotes
Eukaryotes have a well-developed _____ that allows them to be change the shape they ______
Cytoskeleton, move/grow/feed.
When did multicellularity and sexual life cycles arise?
Around 1.2 billion years ago.
When did larger eukaryotes first appear in the fossil record?
Around 600 million years ago.
What is the endosymbiont theory?
The organelles distinguishing eukaryote cells evolved through symbiosis of individual single-celled prokaryotes (bacteria and archaea). The theory holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells represent formerly free-living prokaryotes taken one inside the other in endosymbiosis, around 1.5 billion years ago.
In addition to mitochondria, ______ are thought to be descendents of bacteria that were engulfed by an early eukaryote and became endosymbionts.
Plastids.
______ led to red and green algae, which further evolved into ______
Plastid-bearing organisms, photosynthetic organisms in which red and green algae were engulfed.
Describe early multicellular eukaryotes
Colonies of cells that are connected but show little to not cellular differentiation
Differentiated cell types ________ in a variety of eukaryotic groups.
Arose independently
How is the transition to multicellularity from unicellular ancestors explained in terms of novelty?
Primarily by changes in how existing genes are used, as opposed to a great deal of gene novelty.
Which cells are the most elaborate?
Unicellular protists
How do they accomplish essential biological functions?
With subcellular organelles, instead of organs like multicellular organisms.
What four types of protistan nutritional strategies exist?
Photoautotrophic, heterotrophic, and mixotrophic.
