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Which is actually more ancient, the Bacteria or the Archaea?
Bacteria: Archaea is actually more similar to Eukarya/ "younger" evolutionarily.
What makes bacteria so important to the planet?
- Major decomposers of organic matter - Nitrogen-fixing bacteria increase the efficiency of plant growth - Cyanobacteria are major producers of atmospheric oxygen Bacteria can break down environmental toxins, create life-saving drugs, and manufacture vitamins
Why is the diversity of bacteria so high in the soil?
It has plenty of niches for organisms to live.
What factors in the soil make biodiversity differ from location to location?
- Moisture level - pH - Nutrients - Soil texture - Presence or absence of plants - Oxygen level
How is soil biodiversity sampled? Why has this not led to an accurate picture of what bacteria live in the soil?
- Soil is collected and cultured in a lab by growing it in media in a petri plate - Different types of media or growth conditions will favor the growth of some species and not others.
Before DNA technology, how were bacteria identified?
Through cellular and colony morphology and through gram stains.
Even with DNA technology, what makes identification of bacteria difficult?
The high rate of mutation of bacteria.
How are community diversities compared?
By the species composition and distribution of individuals.
species richness
Total number of species in a region.
Simpson's Reciprocal Index of Diversity
measures probability that two individuals randomly selected from a sample will belong to the same species --high value= greater diversity -- Actually takes into account both richness and abundance of a species --D=1/(n(E)i=1 * p2i
Keystone Species
A species with a large effect on its ecosystem.
Explain the Theory of Evolution by Natural Selection. How does it result in adaptations?
- Heritable variation in phenotypes. Produce more offspring than can be supported. Some traits are better for survival. - Over time, the population has more individuals with the favorable traits.
How does sexual selection differ from natural selection?
- Sexual selection is an organism's ability to obtain a mate - While, natural selection is about an organism's survival traits. - One trait could help an organism's mating (sexual selection), but hurt its fitness (natural selection).
What are examples of adaptations?
- Are inherited characteristics (traits) that help an organism survive and reproduce. - Examples: A peacock's feathers, polar bear's white, thick fur, or a lizard's chameleon.
Can an Adaptation Lose its Fit?
Yes; environments are constantly changing. Therefore, what is beneficial at one time could become needless as an organism's niche evolves.
How can an adaptation also be a trade-off?
One trait may be great for survival, but it may be less beneficial for reproduction and vise-versa.
How is dentition important to a mammal?
It is what determines the type of food an organism can obtain and consume.
What are the four types of mammal teeth?
- Incisors: biting or cutting - Canines: piercing or tearing - Premolars: grinding and crushing - Molars: grinding and crushing
What are the four different feeding groups of animals?
1. Carnivores 2. Herbivores 3. Insectivores 4. Omnivores
What skull traits might be different among different groups of animals?
- Dentition - Jaw size - Eye placement - Hearing abilities
Two limitations scientists face when studying soil biodiversity?
1. Only 1% of bacteria can be sustained in the lab 2. We do not have the technology to study smaller bacteria
What is the feeding strategy of fungi?
They absorb nutrients from living and dead organisms on which they usually live (soil, leaf litter, leaf tissue, or even between human toes).
What are the implications of this feeding strategy on a fungus's morphology?
Their cells are long and filamentous and often form chains called hyphae.
How are fungi different from plants?
- They have chitin in their cell wall and not cellulose. - No chlorophyll or other photosynthetic pigments - Do not make their own food like plants
How do fungi reproduce?
Fruiting body: Produces millions of spores
In what ways are fungi critical to life on the planet?
- Important decomposers - Antibiotics - Can be used to make bread and brew beer - Mutualistic with plants
How do mycorrhizae help plants grow?
Mycorrhizae live with plant roots and in exchange for protection and sugars help the plant absorb water and nutrients.
What is a secondary compound?
Are a diverse array of chemicals that plants have evolved to help their defense.
In what ways are fungi detrimental to organisms on the planet?
They cause diseases on both living crop plants or forest species, harvested grains, and humans.
Why are fungal infections difficult to treat?
-because fungal cells are eukaryotic like human cells and medications targeting fungal cells can damage our own cells
How do plants defend themselves from attack by other organisms?
"Stand and Deliver" defense: By using secondary compounds, they can kill bacteria, inhibit fungal growth, and make their tissue taste noxious to insects.
Why don't plant defenses against organisms always work?
- Altering the environment changes the utility of adaptations. - New fungi can show up that they don't have defenses for - Monocultures make the dispersal of fungi extremely fast and intense
What is capsaicin?
Capsaicin is a great product of evolution, allowing peppers to appear hotter and therefore, be less of a victim to fungi or other predators.
What is behavior, and what types of organisms exhibit behavior?
Behavior is any action that is a response to stimuli; all organisms exhibit behavior.
How is innate behavior different from learned behavior?
- Innate behavior is genetically-based, inherited, and often involuntary. - Learned behavior is a change in behavior due to a specific experience in the organism's life.
How are ultimate causes of behavior different from proximate causes?
- Ultimate causes are the factors that have caused the behavior to evolve over time. - Proximate causes are the immediate environmental stimuli causing the reaction.
What are five questions that may drive behavior?
1. What should I eat 2. Who should I mate with 3. Where should I live 4. How should I communicate 5. When should I cooperate
What type of animal is a flour beetle?
Group of Arthropods known as insects.
How long is the life cycle of a flour beetle?
5 weeks
What environmental factors may affect the behavior of flour beetles?
- Temperature - Food source - Stress - Genetics - Life history - Density
What are some examples of behavior that flour beetles demonstrate?
- "play dead" - Canabilistic behaviors
What are some examples of behavior that flour beetles demonstrate?
- "play dead" - Canabilistic behaviors

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