Origins Flashcards
What are the 3 main groups?
Bacteria. Archeae. Eukaryote.
What does a phylogeny tree show?
Confirms how organisms are related to each other via DNA
What are the two significant evolutionary events?
Eukaryotes acquired chloroplasts and mitochondria by endosymbiosis. Bacteria are responsible.
How many groups are there?
Definitely 7, thought to be 8
How many groups have the capacity to photosynthesis?
6
Describe endosymbiosis (first event)
- Bacteria engulfed by a prokaryotic host
- Genes transferred conversion to organelle
- Produced mitochondria
Describe endosymbiosis (second event)
- Eukaryotic like cell engulfs a prokaryotic photosynthetic cyanobacterium
- Transfer genes and conversion to organelle
- Produces a chloroplast
How did eukaryotes acquire photosynthesis?
Acquired it multiple times by repeated endosymbiosis
What were the three clades that rose from the first eukaryotic organism?
Glaucocystophyte. Green Algae. Red Algae.
How did endosymbiosis contribute to diversity on the planet?
Increased diversity. Helped evolution of multicellular organisms. Diverse groups of multicellular organisms.
What needs to be overcome for multicellularity?
Cell communication - cell signalling.
What are some key events in evolution?
Photosynthesis. Endosymbiosis. Diversification. Multicellularity.
What did green algae evolve into?
Land Plants
How did Land Plants help to change the atmosphere?
Caused a massive reduction in CO2. Falling levels of CO2 caused lower temperatures. This initiated a terrestrial ecosystem and triggered evolution. Lower temperature = plants with broader leaves = increased oxygen levels
How can evolutionary trees be used to explain diversity of life on the planet?
Show how the acquisition of photosynthesis by endosymbiosis led to radiation and diversification
Where do animal and plants originate from?
Aquatic life
What are some features of eukaryotic cells?
Nucleus, cytoskeleton
What is an Amoeba?
Engulfs. Single celled celled but still eukaryotic
What are some features of complex multicellularity?
Evolved many times. Molecular mechanisms of cell adhesion. Cell communication. Different cells and tissues. Regulatory genes. Reproduction. Internal and external environment.
What are some examples of complex response?
Cell signalling (histamine). Opsonization (phagocytosis)
What is a constraint of a multicellular organism?
Getting oxygen to all the cells.
Why was there original multicellular organisms in an aquatic environment?
Oxygen existed in the ocean so multicellular organisms evolved.
What features did sponges have?
Pores
What features did Cnidarians have?
(jellyfish and sea anemone). Two cell layers. Able to stick.
