learning objectives 10 Flashcards
What taxa contains most species that have been named and described?
insects (arthropods)
What are the main characteristics of arthropods?
they have a segmented body, joined appendages, and an exoskeleton
Eukarya
- Eukaryotic cells
- wide range of metabolism
- examples: humans, plants
Archaea
- prokaryotic
- extremophiles
- examples: methanogens, thermophiles
Bacteria
- prokaryotic
- diverse metabolism
- examples: E. coli, streptococcus
Photoautotrophs
- use light for energy
- use CO2 as a carbon source
- example: plants
Chemoheterotrophs
- break down glucose for energy
- use organic compounds for carbon
What unites bacteria and archaea?
both are prokaryotes with no true nucleus and are metabolically diverse
Give an example of a harmful and beneficial bacterium.
- Harmful: Streptococcus (can cause strep throat).
- Beneficial: Non-pathogenic E. coli (found in human intestines).
What are extremophiles? Provide examples from Archaea.
Organisms adapted to extreme environments, e.g., Halophiles (salty environments), Thermophiles (hot environments), Methanogens (anoxic environments).
Who are Archaea more closely related to, bacteria or eukaryotes?
Eukaryotes
What are some traits shared by all eukaryotes but not by bacteria or archaea?
Eukaryotic cells have internal membrane-bound organelles, cytoskeletons, and true nuclei.
Why are protists not considered a true clade?
They are diverse and do not have one exclusive common ancestor.
Which group of algae is most closely related to land plants?
Green algae.
What were the advantages and challenges for plants colonizing land?
- Advantages: Abundant CO2, light, nutrients, no herbivores.
- Challenges: Scarcity of water, lack of structural support.
What are the four main groups of plants?
- Non-vascular: Mosses.
- Seedless vascular: Ferns.
- Gymnosperms: Conifers.
- Angiosperms: Flowering plants.
What defines gymnosperms and angiosperms?
- Gymnosperms: No flowers, seeds exposed on cones.
- Angiosperms: Flowers, seeds protected in fruits.
Why do some angiosperms produce nectar and/or fruit?
- nectar: attracts pollinators (e.g., bees) to transfer pollen between plants
- fruit: after fertilization, fruit aids in seed dispersal by animals (e.g., birds), spreading seeds to new areas
What are the main characteristics of fungi?
Unicellular or multicellular, decomposers, parasites, more closely related to animals than plants.
What are the major shared derived characters of animals?
Chemoheterotrophs, multicellular, eukaryotes with no cell walls, and have skeletons and specialized tissues.
What are the four shared derived characters of chordates?
Notochord, dorsal hollow nerve cord, pharyngeal slits, muscular post-anal tail.
Compare vertebrates, chondrichthyans, and tetrapods.
- Vertebrates: Have a backbone.
- Chondrichthyans: Cartilaginous fish (e.g., sharks).
- Tetrapods: Four-limbed vertebrates (e.g., humans).
Porifera
- sponges; first to branch off
- radial symmetry
Cnidaria
- radial symmetry
- jellyfish
Mollusca
- shells
- octopus
- bilaterally symmetric body
Annelida
- segmented bodies
- earthworms
- bilaterally symmetric body
Nematoda
- cylindrical body shape
- roundworms
- bilaterally symmetric body
Arthropoda
- exoskeleton
- insects/crustaceans
- bilaterally symmetric body
Echinodermata
- shape is spherical, elongated, or star-like in shape
- starfish
- bilaterally symmetric body
Chordata
- notochord
-humans - bilaterally symmetric body
