10 Biodiversity

Question 1

Know that arthropods…

Answer 1

dominate the list of described species (~75%) but that most species are microbes

Question 2

Compare and contrast the 3 domains of life. Give an example of organisms in each.

Answer 2

3 Domains of Life:
1) Archaea - single-celled organisms with no organelles. Has cell walls with little peptidoglycan and found in extreme environments (ex: Thermophiles, found in hot environments)
2) Bacteria - single-celled organism with no organelles. Has cell walls with peptidoglycan and found in various habitats (ex: cocci, lives on teeth)
3) Eukarya - complex, cell with organelles (ex: humans)

Question 3

Give an example of a photoautotroph and chemoheterotroph. Explain why each organism is given that label. Explain what each part of those two words mean.

Answer 3

Photoautotroph: make their own food using light energy (ex: plants)
- given this label because they use light energy (photo) to synthesize (auto) glucose (troph)
- Photo = Light
- Auto = Self (gets its own food)
- Troph = Eat

Chemoautotroph: make their own food using chemical energy
(ex: sulfur bacteria)
- given this label because they break down chemical reactions (chemo) to gain (gain) glucose (troph)
Chemo = Breaks down glucose
Auto = Self (get its own food)
Troph = Eat

Question 4

Understand the phylogenetic relationships between Bacteria, Archaea, Animals, Plants and Fungi. Be able to interpret a phylogenetic tree to explain patterns of relationships between these groups.

Answer 4

• Eukarya and archaea are sister taxa (two groups of organisms that are each’s closest relatives in a phylogenetic tree)
• Archaea and bacteria branched from the same common ancestor
• animals are more closely related to fungi than plants
• Animals, plants and fungi are part of eukarya domain

Question 5

What important ecological roles do Bacteria play? Give an example of a harmful and a beneficial Bacteria species or genus.

Answer 5

Bacteria decomposes dead matter, recycling nutrients, forming beneficial relationships with other organisms.

Harmful: E. Coli - causes food-borne illnesses
Beneficial: Rhizobia 0 helps plants by fixing nitrogen from the air

Question 6

Define Extremophiles. Give examples of categories of Archaea that are found in different extreme environments

Answer 6

Extremophiles are organisms that thrive in extreme environments that are typically inhabitable to most organisms

Examples:
- Halophiles: live in highly saline environments (dead sea)
- Thermophiles: live in extremely hot environments (volcanic springs)
- Methanogens: archaea that release methane as a by product of their unique ways of obtaining energy

Question 7

List cellular traits shared by all eukaryotes but not by Bacteria or Archaea

Answer 7

Membrane-Bound Organelles

Question 8

Describe the main characteristics of protists

Answer 8

• Mostly unicellular
• Largely aquatic
• Tremendous phylogenetic diversity

Question 9

Explain the major challenges faced when plants established populations on land and the advantages of living on land

Answer 9

Challenges:
- Relative scarcity of water
- Lack of structural support
- Herbivores

Advantages:
- access to stronger sunlight for photosynthesis
- access to a greater concentration of carbon dioxide in the air as compared with the concentration in the water
- many possible pollinators
- many types of seed dispersal
- ability to grow taller

Question 10

Compare and contrast the 4 main groups of plants (nonvascular, seedless vascular,
gymnosperms and angiosperms). Given a description of a plant species with
relevant characteristics (e.g., “this plant has flowers,”) be able to classify the plant
into the appropriate group.

Answer 10

• nonvascular: Non-woody, occur in moist environments, form low mats, e.g. moss
• seedless vascular: occur in moist environments, e.g. ferns
• gymnosperms: no flowers, seeds exposed on modified leaves that form cones, seeds not enclosed in ovaries, e.g. pine tree
• angiosperms: seeds protected in fruits, seeds enclosed in ovaries, e.g. sunflower

Question 11

Discuss how the origin of vascular tissue provided plants with an advantage over
non-vascular plants

Answer 11

• Efficient Transport: vascular tissue efficiently moves water, nutrients and sugars throughout the plant, enabling larger growth and better distribution of resources
• Structural Support: vascular tissues gave structural support, allowing them to grow tall and get more sunlight
• Expanded Habitat Range: vascular tissue allowed plants in a wider range of environments by enhancing their ability to survive and reproduce

Question 12

Explain how the evolution of seeds provided plants with an advantage over seedless
plants. Give an example of a mechanism plants use to disperse their seeds.

Answer 12

Seeds provide plants with advantages such as protection, nutritional reserve, dormancy, and dispersal, contributing to their evolutionary success and ability to thrive in diverse environments.
(ex: Pollen - contains sperm, packaged to travel, is carried long distances by wind or animals)

Question 13

Explain why some angiosperms produce nectar and/or fruit

Answer 13

to attract pollinators like bees and birds, aiding in pollination. they produce fruit to protect and disperse seeds, which feed pollinators who can also spread the seeds to ensure its survival

Question 14

Explain what a seed consists of

Answer 14

• Embryo: young plant inside the seed that has basic structures that will develop into the mature plant
• Food: seeds contain stored food reserves to nourish the embryo during germination and early growth
• Hard Protective Coat: provides physical protection for embryo and food reserves

Question 15

List the jobs that a seed needs to accomplish when it begins to grow, along
with the structures it uses to accomplish them.

Answer 15

• Find water (roots)
• Make sugar/food via photosynthesis (photosynthesis)

Question 16

Describe the job of a leaf and
how the sugar made by leaves fuels the rest of the terrestrial food chain.

Answer 16

Job of a Leaf: make sugar through photosynthesis

Sugar made through photosynthesis fuels the rest of terrestrial food chain by serving as the main energy source for other organisms. These organisms eat the plant which gives them sugar (fuel). When organisms die, decomposers break down their bodies, returning nutrients to the soil for new plant growth

Question 17

Describe the role of mushrooms in the life of a soil fungus

Answer 17

Mushrooms are the reproductive structures of soil fungi. They release spores, which are like fungal seeds, into the environment to spread and reproduce. So, the role of mushrooms in the life of a soil fungus is reproduction and dispersal.

Question 18

Describe what soil fungi provide to plants (metals, water) and what plants
provide to soil fungi in return (sugar)

Answer 18

Soil fungi provide plants with nutrients like metals and help them absorb water. In return, plants give soil fungi sugar produced through photosynthesis.

Question 19

Describe the main characteristics of fungi, including the basic body plan of
multicellular fungi

Answer 19

• Basic body plan of multicellular fungi: thread-like structures called hyphae, which intertwine to form a network called “mycelium”. This serves as the main body of the fungus and branches out to explore and absorb nutrients from the surrounding environment
• Chitin Cell walls: provides structural support and protection for fungal cells
• Reproduction by Spores: reproduce by producing spores

Question 20

Describe the major traits that animals share.

Answer 20

• Multicellularity
• Heterotrophy
• Nervous System
• Sexual Reproduction
• Sensory Organs

Question 21

Compare and contrast the following phyla: Porifera, Cnidaria, Mollusca, Annelida,
Nematoda, Arthropoda, Echinodermata, Chordata. For each phylum in that list:
o List 2-3 major characteristics that define the phylum.
o Be able to give an example of an animal in the phylum.
o Define the kind of symmetry that animals in the phylum have.
o State whether the animals in that phylum are segmented, shed their outer
covering in order to grow, have true tissues, have a dorsal hollow nerve cord, are
bilaterally symmetric (at some life stage), have a calcium carbonate shell, or
have an exoskeleton made of chitin and protein.
(Some of this is only in the reading)

Answer 21

Porifera: Base of evolutionary tree no true tissues but they are basal animals with multiple cell types
sponges

Cnidaria: where true tissues evolve
Eumetazoa and movements

Mollusca: Mantles snails slugs octopus

Annelida: worms segmented worms-double check

Nematoda: exoskeletons not segmented

Arthropoda: segmented exoskeletons

Echinodermata: more similar to chordates, pentameral symmetry as adults

Chordata: dorsal nerve chord

Question 22

Given a picture of an animal with clearly visible features or a description of the
animal, identify which of the phyla listed above it belongs to.

Answer 22

Notes

Question 23

Given a phylogenetic tree of animals, draw the character transitions for these traits
on the tree: bilateral symmetry, having true tissues

Answer 23

Notes

Question 24

List the 4 characters that chordates share but other animals do not. Explain the
function of the notochord and dorsal hollow nerve cord and describe the forms they
take in humans. (This is in the reading.)

Answer 24

-Has true tissues
-Bilaterally symmetric in at least one life stage
-Visibly segmented
-Dorsal, hollow nerve cord
Function of Notochord: a cartilaginous skeletal rod supporting the body in all embryonic and some adult chordate animals

Hollow nerve cord: The dorsal hollow nerve cord is derived from ectoderm that rolls into a hollow tube during development. In chordates, it is located dorsally to the notochord. In contrast, the nervous system in protostome animal phyla is characterized by solid nerve cords that are located either ventrally and/or laterally to the gut

Form they take in humans: The dorsal hollow nerve cord develops into the central nervous system: the brain and spine.
A notochord is a primitive beginning to the backbone.

Question 25

Explain why the evolution of the amnion enabled reproduction on land. List the
major animal groups within the amniote taxon. (Some of this is in the reading and
some of this may have been covered in the Phylogenetics topic.)

Answer 25

reptiles, birds, and mammals
this enabled reproduction on land because…
The amniotic egg was an evolutionary invention that allowed the first reptiles to colonize dry land more than 300 million years ago. Fishes and amphibians must lay their eggs in water and therefore cannot live far from water. But thanks to the amniotic egg, reptiles can lay their eggs nearly anywhere on dry land

Question 26

Compare and contrast Vertebrates, Chondrichthyans, and Tetrapods. Know the
features that define each group, and be able to give an example of an organism in
each. Understand the evolutionary relationships between these groups.

Answer 26

• Vertebrates: Backbone composed of vertebrae, human
• Chondrichthyans: vertebrates Skeleton is predominantly cartilage, sharks and rays
• Osteicthyans: Bony (ossified) skeleton of calcium phosphate, ray-finned fish, lobe
  finned fish, tetrapods, eel actually bones!
• Tetrapods: lobe-finned ancestor developed limbs with digits, facilitating colonization of land,
  lizard
  -these are nested clades so the evolutionary relationships is that they are all vertebrates

Question 27

For each of these vertebrate groups (Mammals, Chondrichthyans, Amphibians,
Birds, Ray-finned fishes, Lobe-finned fishes, Reptiles), you should be able to:
o List 1-2 major characteristics that define the group.
o Give an example of an animal in the group.
o State whether most of the animals in that group have these traits: ability to
reproduce away from water, amnion, endothermic, jaws, external ears, hair/fur,
legs.
(Some of this is only in the reading.)