Biology 2: Exam 3 (plants 1 and 2[nonvascular & seedlass vascular plants & vascular plants & seed plants], animal diversity, invertebrate diversity, chordates, fungi)

what are plants derived from?

charophytes

derived traits of plants

1. alternation of generations

2. multicellular, dependent embryos

3. walled spores produced in sporangia

4. multicellular gametangia

5. apical meristems

sporangia

multicellular organs present in the sporophyte (2N) stage that produce spores with walls composed of sporopollenin

apical meristems

are localized regions of cell division at the tips of roots and shoots that enable roots and shoots to elongate.

alternation of generations

1.The gametophyte produces haploid gametes by mitosis.

2.Two gametes fuse to form a zygote.

3.The zygote develops into a multicellular diploid sporophyte.

4.The sporophyte produces unicellular haploid spores by meiosis.

5.The spores develop into multicellular haploid gametophytes.

what clade are plants a part of?

embryophytes

Bryophytes are a monophyletic grouping.

T or F?

F

Vascular plants form a monophyletic grouping.

T or F?

T

seed

an embryo packaged with a supply of nutients inside a protective coat.

what type of plants are bryophytes?

nonvascular

protonema

A mass of green, branched one-cell-thick filaments produced by germinating moss spores.

rhizoids

Long tubular cells or filaments of cells that anchor nonvascular plants to the ground

gametangia

Multicellular structures that produce gametes and are covered by protective tissue.

archegonia

Female gametangia

antheridia

Male gametangia

foot

Sporophyte structure that absorbs nutrients from the gametophyte

seta

Stalk that conducts nutrients from the foot to the sporangium

capsule

Sporangium that produces spores by meiosis.

nonvascular plant cycles are dominated by___.

gametophytes

nonvascular plant cycle

1.Spores develop into protonemata.

2.The haploid protonemata produce "buds" that divide by mitosis and grown into gametophytes.

3.Sperm must swim through a film of moisture to reach the egg.

4.The zygote develops into a sporophyte embryo.

5.The sporophyte grows a seta that emerges from the archegonium.

6.The sporophyte remains attached to and nutritionally dependent on the gametophyte.

7.Meiosis occurs and haploid spores develop in the capsule. When the capsule is mature, the spores are released.

vascular plant cycles are dominated by ___.

sporophytes

seedless vascular plants

•date to 425 mya

•The evolution of vascular tissue allowed vascular plants to grow taller than the bryophytes, which gave them a competitive advantage.

•the sperm of seedless vascular plants, like bryophytes, are flagellated and must swim through a film of water to reach eggs.

•mostly found in damp environments.

life cycle of a fern

1.Sporangia release spores.

2.Each gametophyte develops sperm and egg producing organs.

3.Sperm swim toward an attractant produced by archegonia.

4.A zygote develops into a new sporophyte and the young plant grows out of a parental archegonium.

5.The underside of a sporophyte's reproductive leaves contain sori, or clusters of sporangia.

xylem

•conducts most water and minerals and includes tube-shaped cells, known as tracheids that carry water and mineral up from the roots.

•The water conducting cells of the xylem are dead at functional maturity and their cell walls are strengthened by the polymer lignin.

phloem

•cells that are arranged into tubes that distribute sugars, amino acids, and other organic compounds.

•These cells are alive at functional maturity.

roots

•are organs that absorb water and nutrients from the soil. They also anchor vascular plants in the ground.

leaves

•serve as the primary photosynthetic organ of vascular plants.

•Classified as microphylls if they are spine-shaped and supported by a single strand of vascular tissue. (Lycophytes)

•Classified as megaphylls if they have highly branched vascular systems. (all other vascular plants)

sporophylls

•modified leaves that bear sporangia.

•vary greatly in structure from the sori of ferns to the cone-like structures of gymnosperms and the flower parts of angiosperms.

•can be classified as homosporous or heterosporous.

homosporous

Referring to plants in which a single type of spore develops into a bisexual gametophyte having both male and female sex organs.

heterosporous

Referring to a plant species that has two kinds of spores: microspores, which develop into male gametophytes, and megaspores, which develop into female gametophytes.

monilophytes

•ferns, horsetails, whisk ferns, and their relatives

•More closely related to seed plants than to lycophytes.

•Have megaphyll leaves

•Vast majority are homosporous (a few ferns are not)

seed plants basics

•have reduced gametophytes

•have these characteristics: heterospory, ovules, pollen

•these adaptations help protect seeds from terrestrial environment pressures like uv radiation and drought

•these adpatations resulted from freedom from dependency on water for fertilization

integument

Layer of sporophyte tissue that envelops and protects the megasporangium. Gymnosperms generally have one integument and angiosperms have two.

ovule

•The entire structure including megasporangium, megaspore, and the integument. (egg cell)

pollen grain

Develops from a microspore and consists of a male gametophyte enclosed within the pollen wall, whose outer layer is made from molecules secreted by sporophyte cells.

pollination

Transfer of pollen to the part of a seed plant that contains the ovules.

evolutionary advantages of seeds

-They may remain dormant for days to years, until conditions are favorable for germination

-They have a supply of stored food

-They may be transported long distances by wind or animals

life cycle of a pine (gymnosperm)

1. Cone Formation - Trees produce ovulate (female) and pollen (male) cones.

2. Pollen Production & Dispersal - Microsporocytes undergo meiosis to form haploid microspores, which develop into pollen grains that are released.

3. Pollination & Pollen Tube Growth - Pollen grains reach the ovule, germinate, and form a pollen tube that penetrates the megasporangium.

4. Megaspore & Gametophyte Development - The megasporocyte undergoes meiosis, forming a megaspore that develops into a female gametophyte containing egg cells.

5. Fertilization & Seed Formation - Sperm cells travel through the pollen tube to fertilize the egg, leading to seed development, completing the cycle.

Gymnosperm Diversity: Cycadophyta

•There are 350 of living cycads.

•Cycads have large cones and palmlike leaves.

•Like seedless vascular plants, cycads have flagellated sperm.

•Cycads are among the most endangered of all plant groups and ~ 75% of their species are threatened by habitat loss.

Gymnosperm Diversity: Ginkgophyta

•Ginkgo biloba is the only extant species from this phylum.

•Like cycads, they have flagellated sperm.

•Its fanlike leaves turn gold in Autumn and G. biloba is a popular ornamental in cities.

Gymnosperm Diversity: Gnetophyta

•Consists of three genera.

-Welwitschia, Gnetum Ephedra

•Some species are tropical, whereas others live in deserts.

Members of this group vary widely in appearance and are grouped together based on molecular data

Gymnosperm Diversity: Coniferophyta

•Largest phylum of gymnosperms that consists of approximately 600 species, many of which are large trees.

•Most species have woody cones, but there are a few with fleshy cones.

•Most conifers are evergreens; however, some species, such as the tamarack, are deciduous.

•Dominate vast expanses of northern forests sometimes referred to as boreal forests or taiga.

angiosperm basics

•Commonly referred to as "flowering plants".

•Angiosperms are the dominant plant group alive today and there are over 290,000 (about 90% of all extant plant species) species, all of which are in the phylum Anthophyta.

•The defining feature of angiosperms is the presence of reproductive structures known as flowers and fruits.

sepals

at the base of the flower, usually green, and enclose the flower before it opens.

petals

usually brightly colored and can aid in attracting pollinators.

stamen

microsporophylls that produce microspores that develop into pollen grains containing male gametophytes.

filament

the stalk of a stamen

anther

terminal sac of a stamen where pollen is produced.

carpels (pistil)

megasporophylls that produce megaspores that give rise to female gametophytes.

stigma

sticky tip of carpel that receives pollen

style

connects stigma to ovary

ovary

base of carpel that contains one or more ovules

fruit

•the mature ovary of a flower that protects dormant seeds and often functions in their dispersal.

•Some fruits are fleshy, and some fruits are dry.

•Some dry fruits split open at maturity to release seeds, while others remained closed.

•The dry, wind-dispersed fruits of grasses, are a major food source for humans.

fruit adaptations that enhance dispersal

•Many seeds have evolved to be dispersed by the wind.

•Many seeds within fruits eaten by animals are still viable after passing through the digestive tract of the animal.

•Other fruits can adhere to animals, which allows for a different mechanism of animal-mediated dispersal.

angiosperm lifecycle

1. Spore Formation - Megasporangia produce megaspores (female) and microsporocytes produce microspores (male).

2. Pollen Development - Microspores develop into pollen grains.

3. Pollination & Pollen Tube Growth - Pollen grains travel through the style, forming a pollen tube that reaches the ovule.

4. Double Fertilization - One sperm fertilizes the egg (zygote), and the other fertilizes the central cell, forming the endosperm (food supply).

5. Seed & Sporophyte Development - The zygote develops into an embryo inside a seed, which later germinates into a mature sporophyte.

embryo sac

The female gametophyte.

micropyle

A pore in the integument of the ovule that the pollen tube penetrates.

double fertilization

One fertilization event leads to zygote and the other produces a triploid cell known as endosperm (food source); unique to angiosperms

cotyledons

initial seed leaves of the zygote

Angiosperm Diversity: Basal Angioperms

•Extant basal angiosperms consist of 3 lineages of which are only about 100 species.

•The most basal lineage is represented by a single species, Amborella trichopoda, which only occurs on the South Pacific island of New Caledonia.

•The next most basal lineage consists of water lilies.

•The final basal lineage consists of star anise and its relatives.

Angiosperm Diversity: Magnoliids

•There are about 8,500 species in this group including magnolias, laurels, and black pepper plants.

•More closely related to monocots and eudicots than to basal angiosperms.

•Includes both woody and herbaceous species.

Angiosperm Diversity: Monocots

•About 25% of angiosperm species are monocots (~ 72,000 species)

•Large groups include orchids, grasses, and palms.

•Grasses, such as corn, rice, and wheat are important food sources for humans.

Angiosperm Diversity: Eudicots

•More than two-thirds of angiosperms are eudicots (~ 210,000 species).

•The legume family, which includes, peas and beans, is the largest group.

•Other well-known eudicots include roses, strawberries, apples, and pears, as well as oak, walnut, maple, willow, and birch.

animal basics

•heterotrophs

•typically ingest their food and digest it internally using enzymes produced within the body.

•Most animals have cells that are organized into tissues, or groups of similar cells that act as a unit.

•Most animals reproduce sexually and have life cycles that are dominated by the diploid stage.

What is the mesohyl in a sponge?

A gelatinous matrix between two layers of cells; acts like connective tissue.

What is the epidermis in a sponge?

The outer layer of tightly packed cells that protects the sponge.

What are pores (ostia) in a sponge?

Small openings that allow water to enter the sponge's body.

What is the spongocoel?

The central cavity where water collects after passing through pores.

What are choanocytes (collar cells)?

Flagellated cells lining the spongocoel; they trap food particles with their collars.

What is the osculum?

A large opening at the top of the sponge where water exits.

What are amoebocytes?

Mobile cells that transport nutrients, make skeletal fibers, and can become other sponge cells.

What type of symmetry do cnidarians have?

Radial symmetry.

What are the two body forms of cnidarians?

Polyp (sessile) and Medusa (mobile).

What are cnidocytes?

Specialized stinging cells used to capture prey.

What are nematocysts?

Organelles inside cnidocytes that inject venom into prey.

Which cnidarians produce a medusa?

Medusozoans like jellies and box jellies.

What body form do anthozoans have?

Polyps only.

What builds coral reefs?

Coral polyps that secrete calcium carbonate exoskeletons.

What type of body symmetry do lophotrochozoans have?

Bilateral symmetry.

Name three major lophotrochozoan groups.

Flatworms, molluscs, annelids.

Why are flatworms flat?

Their flat shape increases surface area for gas exchange.

Do flatworms have a body cavity?

No, they are acoelomates.

What are the three main body parts of molluscs?

Foot, mantle, visceral mass.

What group of molluscs includes snails and slugs?

Gastropods.

What group of molluscs includes clams and oysters?

Bivalves.

What group of molluscs includes octopuses and squids?

Cephalopods.

What type of body plan do annelids have?

Segmented body plan.

What are the two major clades of annelids?

Errantia and Sedentaria.

What is molting in ecdysozoans?

Shedding of the exoskeleton to grow.

Do nematodes have a circulatory system?

No, they lack a circulatory system.

What is a famous model nematode organism?

Caenorhabditis elegans (C. elegans).

What covers the body of arthropods?

A tough cuticle (exoskeleton).

What groups are included in arthropods?

Chelicerates, myriapods, crustaceans, and insects.

What is the difference between holometabolous and hemimetabolous insects?

Holometabolous insects have complete metamorphosis; hemimetabolous insects have incomplete metamorphosis.

What clade do insects and crustaceans form?

Pancrustacea.

What type of symmetry do echinoderm larvae have?

Bilateral symmetry.

What system helps echinoderms move?

Water vascular system.

What are lancelets?

Fish-like filter feeders that are mostly benthic.

What are sea squirts?

Sessile marine filter feeders that produce free-swimming larvae.

What are key characteristics of seed plants?

Reduced gametophytes, heterospory, ovules, pollen.