Biology Midterm

According to Darwin, what was the mechanism by which adaptation occurred?

Natural selection

Contrast analogous and homologous structures.

Homologous are inherited from a common ancestor. Analogous serve the same function and are inherited independently.

Structures or organs that are no longer functional.

Vestigial Structures

Examples of biochemical evidence that supports the hypothesis of common descent.

Use of the same DNA triplet code and the same 20 amino acids in the protein of all organisms.

Who developed the 2-name system?

Carolus (Carl) Linnaeus

How are Eukarya domain cells different from other domains?

Consists of organisms whose cells have a nucleus.

Describe distinguishing characteristics between Fungi, Plantae, and Animalia.

Fungi: heterotrophs, chitin cell wall, yeast/molds. Plantae: autotrophs, cell wall, conifers. Animalia: heterotrophs, no cell wall, lion/elephant.

What is the fruiting body of a sac fungi called?

The ascocarp.

Which fungi is the source of penicillin?

Penicillium

How do cell walls in fungi differ from plants?

Fungal cell walls lack chloroplasts and are made of chitin instead of cellulose.

Explain Mycorrhizal symbiosis.

Mutualistic relationship between soil and fungi and the roots. Fungus gives plant minerals while plant gives fungus carbs.

What is the name given to the tangled mass of hyphae filaments that make up the vegetative body of a fungus?

The thallus, composed of mycelium.

What is meant by alternation of generations?

2 alternating forms (sexual & asexual) in the life cycle of a plant.

List several adaptations plant made for life on land.

\-waxy cuticle -tracheids -3d tissues -haploid & diploid generations

What is the function of the xylem?

Transports water and nutrients to leaves and provides mechanical support and storage.

What is the function of the phloem?

Transports carbs from source to sinks through sieve elements.

What is the dominant “generation” in mosses?

Haploid generation.

During modern times, what plants are considered the dominant plants?

Angiosperms.

What are the main vegetative organs of a plant?

Root, stem, leaf.

What are the main reproductive organs of a plant?

Stamen and pistil.

What is the main function of root hairs?

Uptake water and nutrients from rhizosphere.

What is the main function of the stem?

Support leaves, conduct water and minerals to leaves.

Which organ of the plant is the main photosynthetic organ?

The leaves.

Thigmotropism

Directional growth in response to touch.

Gravitropism

Directional response to environment, shoots go up & roots go down.

Phototropism

Directional response to light.

What is abscission?

Natural detachment of parts of a plant

What is the function of ethylene?

Ripens fruit, brings abscission

What is the function of cytokinin?

Cell division, prevents senescene. Prolongs shelf life.

What is the function of auxins?

Promotes growth, prevents loss of leaves. Herbicide.

What is the function of abscisic acid?

Maintains seed and bud dormancy. Thinner.

Male reproductive structure of a plant

Stamen: pollen sac, anther, filament

Female reproductive structure of a plant

Pistils: ovary, ovules, egg, stigma, style

Where are the ovules contained?

In the ovary.

From what structure do seeds develop?

The ovules.

What would be the purpose of brightly colored petals on a plant.

To attract pollinators.

Describe seed dispersal method of seeds with wings or plumes.

Wind, use of tiny “parachute”, can travel up to 10km

Describe seed dispersal method of seeds with wooly hairs.

Wind, use of tiny “parachute”, can travel up to 10km

Describe seed dispersal method of seeds within a fleshy fruit.

Disperse from parent plant or wind / animals, do not compete with parent plant for nutrients.

What is the function of auxins

Promotes growth, prevents loss of leaves. Herbicide.