BIO1000 - Exam 2

Macroevolution

The evolution of groups larger than an individual.

Which traits do taxonomists use to identify species?

1. Morphological traits
2. Ability tot interbreed
3. DNA sequence homologies
4. Ecological and evolutionary relationships

How are morphological traits used to identify species?

They use physical characteristics such as colors, shapes, and size.

For microorganisms, they use cellular structure and morphology.

How is reproductive isolation used to identify species?

Members of different species are unable to interbreed.

What are the limitations of using reproductive isolation to identify species?

1. It is difficult if populations don’t overlap in the geographic area.
2. It doesn’t apply to asexually reproducing species.
3. It doesn’t apply to extinct species and fossils.

How is molecular data (gene sequences) used to identify species?

You can compare sequences, gene order, structure, and number of chromosomes.

Phylogenies can be used as metrics to distinguish species.

How are ecological traits used to identify species?

Habitat preferences and natural history can be used.

What are the limitations of using ecological traits to identify species?

Many different species overlap in their preferences.

What are the most important benefits that humans derive from plants?

Food, fiber, shelter, medicine, and fuel.

What are the key characteristics of plants?

Multicellular eukaryotic, photosynthesis autotrophs, and apical meristems.

What are the names of two extant species of organisms similar to the early ancestors of land plants?

Stretophytes and bryophytes

What are the key characteristics of Streptophytes?

Distinctive type of cytokinesis plasmodesmata, sexual reproduction using egg and smaller sperm.

What are the key characteristics of embryophytes?

Stomata, apical meristems.

Cuticle

An outer layer that covers the surface of exposed tithes made of wavy material that protects plants from desiccation and block pathogens.

What is alteration of generations?

Allows for both the dynamic and volatile act of sexual reproduction and the steady and consistent act of asexual reproduction.

What are the key characteristics of Bryophytes?

They need moisture for sexual reproduction.

They lack vascular tissues that confer support, water, and nutrient transport.

What are Byrophytes?

The informal group name for mosses, liverworts, and hornworts.

Describe the life cycle of mosses.

Haploid male plants produce sperm in antheridia which travels to the an archegonia of female plants via water. Once inside the archegonia, the egg is fertilized and becomes a sporophyte which depends on the gametophyte for nutrients. As it grows, the gametophyte is pushed upwards and covers a calyptra with teeth to hold the mature spores. These spores move with the wind when the teeth open and if they land in a suitable area, the cycle starts again.

What are the advantages of a dominant sporophyte life cycle?

Fertilization and dispersal of new/next generation timed with environmental conditions.

What are the characteristics of tracheophytes?

1. Water and nutrient conducting vascular tissues
2. Stomata common on plant surfaces
3. True stems, leaves, and roots
4. ADominant sporophyte generation

What are the differences between microphylls and megaphylls

Microphylls are defined as leaves of small size, with simple venation (one vein) and associated with steles that lack leaf gaps (protosteles). By contrast, megaphylls are defined as leaves of generally larger size, with complex venation and associated with leaf gaps in the stele.

What are Lycophytes?

They are a class of spore-bearing vascular plants, comprising more than 1,200 extant species. They produce the simplest, most ancient leaves (lycophylls or microphylls.)

What are Pterophytes?

Free-sporing vascular plants that have a life cycle with alternating, free-living gametophyte and sporophyte phases that are independent at maturity.

What are the characteristics of Pterophytes?

1. Reproduction is limited by dry conditions
2. They depend on gametophytes briefly, then become independent
3. They are dominant during the Carboniferous

Describe the life cycle of ferns.

They have two different stages, namely sporophyte, and gametophyte. Sporophyte releases spores, and they are diploid, gametophyte releases gametes, and they are haploid. So ferns undergo two generations of plants to complete their life cycle, a life cycle that is called the alternation of generation.

What are Progymnosperms?

A group of woody ancestors of present gymnosperms and angiosperms. They inherited seeds from gymnosperms and angiosperms.

What are some ecological advantages of seeds over spores?

1. The embryo is enclosed in a protective cover or seed coat, which protects the seeds from physical, temperature-related, or water damage.
2. Seeds are able to remain dormant in the soil and can wait for favorable conditions.
3. Can store considerable amounts of food.

What are the characteristics of Gymnosperms?

1. They were dominant during the Mesozoic Era
2. Their dominance coincided with the emergence of dinosaurs

What is plant wood?

It’s a tissue composed of pipe-like arrays of empty and water-conducting cells.

What are Gymnosperms?

Plants with “naked seeds,” meaning seeds are not enclosed by a fruit.

What are the Cycads?

Gymnosperms that are distinguished by crowns of large pinnately compound leaves and by cones.

What are the characteristics of Cycads?

1. There are 300 species today
2. They have palm-like leaves
3. Their cones emit odors that attract beetles, which carry pollen to ovules

What is Ginkgo?

One of the oldest living tree species.

What are the characteristics of Ginkgo?

1. Has two-lobed shaped leaves
2. They are nearly extinct in the wild
3. They’re usually planted along city streets
4. They can live for more than 1,000 years and grow to 30 meters in height

What are conifers?

The most diverse lineage of gymnosperms. They are common in mountains and high-latitude forests.

Are pinecones fruits?

No, because they don’t have seeds.

What are Gnetales?

A division of plants grouped within the gymnosperms. They have broad leaves similar to tropical planes, vines, shrubs, or trees in tropical Africa or Asia.

What are key innovations in Angiosperms?

1. Broader leaves
2. Endosperm in seeds
3. Flowers
4. Fruits

Sepals

The green outer layer of a flower.

Petals

Often colorful, at the top of a flower.

Stamens

The part of the flower that produces pollen.

Carpels

The part of the flower that produces ovules.

Describe the process of double fertilization.

This is the key feature of Angiosperms.


1. One sperm cell fertilizes egg to become an embryo (diploid -- 2n)
2. Another sperm cell fuses with two nuclei of the gametophyte tissue to form endosperm (triploid -- 3n)
3. Ovule’s integument develops into a protective seed coat

What is pollination?

The process of the transfer of pollen from an anther to a stigma from flowers of the same species, usually from different individuals.

Describe the process of coevolution between flowers and pollinators?

Explains how pollinators and food-rewarding flowers involved in specialized mutualisms could, over time, develop long tongues and deep tubes, respectively. It was first mentioned by Charles Darwin. He correctly predicted a moth with a 28 cm long tongue based on a particular species of plant with long flower

What are the differences between monocots and eudicots?

1. They have different number of petals, monocot has 6, and eudicot has 5 petals
2. Monocots has a single cotyledon, euidcot has two cotyledons

What are the similarities of Animals and Fungi?

1. They are both heterotrophic (can’t produce their own food)
2. They both have absorptive nutrition
3. They both store surplus food as glycogen

What are the many uses that we, humans, have made of fungi?

1. Food, wine
2. Pest control
3. Used two break down plant materials for bio fuel
4. Antibiotics
5. Industrial products (citric acid and glycerol)

What is Mycelium?

A haploid, it can be extensive and inconspicuous

How does a fungus grow?

it is done by two coordinated mechanisms: osmosis and cytoplasmic streaming.

What is osmosis?

This occurs when molecules from the substrate pass through the fungus semipermeable cell membrane following a gradient from a less concentrated solution into a more concentrated one inside the cell (I.e., equalizes concentrations on both sides)

what is cytoplasmic streaming?

The directed flow of the cytoplasm towards a region of the cell.

What are the differences between sexual and asexual reproduction among fungi?

They usually reproduce both sexually and asexually. the asexual cycle produces mitospores, and the sexual cycle produces meiospores. Even though both types of spores are produced by the same mycelium, they are very different in form and easily distinguished

What is the relevance of fungi to the Earth’s ecosystems?

They break down organic debris such as dead organisms and waste.

They also release CO2 into the air and other minerals to soil and water.

What are some negative effects of fungi on human health?

1. Some of the fungi are responsible for food spoilage and many allergies.
2. Athlete’s foot fungus
3. Yeast infections
4. Poisoning

What are some negative effects of fungi on plant health?

1. >5,000 species of fungi can cause serious crop diseases
2. Specialized balloon-shaped cells (haustoria) aid in absorption of nutrients from

plant hosts


3. Control achieved through toxic fungicides, resistant crops and control over the import of infected plants

What are some negative effects of fungi on animal health?

1. Some fungi cause serious diseases in the wildlife.
2. Chytridiomycosis (Pandemic associated with declining frog populations)
3. White nose syndrome in bats

What is white nose syndrome?

A disease caused by the fungus Pseudogymnoascus destructans. The disease is estimated to have killed millions of bats in eastern North America since 2006 and can kill up to 100% of bats in a colony during hibernation. Bats catch the fungus from physical contact with infected bats or from the surfaces of caves. Humans can also spread the fungus on shoes, clothing, or gear.

Describe beneficial associations of fungi with insects and plants.

1. Some species of fungi are able to suppress the growth of insects and nematodes that may cause harm to agricultural crops.
2. Fungus can form symbiosis: close relationships with other species
3. The insects also patrol their garden, preying on competing fungi. Both ants and fungi benefit from the association. The fungus receives a steady supply of leaves and freedom from competition, while the ants feed on the fungi they cultivate.

What are the advantages of using biopesticides?

1. Inherently less toxic han conventional pesticides.
2. Specific, affect only the target pest (e.g., don’t affect birds or mammals)
3. Effective in small quantities and decompose quickly (avoid pollution)