General Biology 2: Exam 3

Green algae

Green algae

Closest living relative to plants

Major land plant groups

Non-vascular, seedless vascular, seed, flowering/fruiting plants

Non-vascular plants

Lacks vascular tissue

Vascular tissue

Specialized groups of cells that conduct water or dissolved nutrients throughout the plant body. (Also gives support)

Moss

Type of nonvascular plant that uses spores, not seeds, for reproduction and dispersal

Seedless vascular plants

Have well developed vascular tissue but use spores for reproduction instead of seeds

Seed plants

Plants that have vascular tissue and make seeds

Seeds

An embryo and nutritive tissue, surrounded by a tough protective layer

Gymnosperms (naked seeds) and angiosperms or flowering plants (encased seeds)

Types of seed plants

Similarities between green algae and land plants

Same chloroplast structure, similar thylakoid arrangements, and similar structure and composition of cell walls, sperm, and peroxisomes

Gametophyte

Multicellular haploid phase

Sporophyte

Multicellular diploid phase

Alternation of generations

A phase all land plants undergo where they have gametophytes and sporophytes

Gametophyte-dominant life cycle

Found in nonvascular plants, which are largely dependent on gametophyte for nutrition while the sporophyte is small and short lived

Sporophyte-dominant life cycle

In ferns and other vascular plants, sporophyte is much larger and longer lived than gametophyte. The gametophytes of gymnosperms and angiosperms are microscopic

Sporophyte-dominated life cycle advantage

Diploid cells can respond to varying environmental conditions more efficiently than haploid cells can. This is especially true if individual is heterozygous at many genes

Pollen grains

Allow plants living in dry habitats to reproduce efficiently. (Tiny male gametophytes surrounded by tough coat of sporopollenin, can be exposed to air for long periods of time without drying out, carried to female gametophyte by win or animals)

Flowering plants (angiosperms)

Most diverse land plants living today. Reproductive success around the flower

Anatomy of the flower

Stamen contains anther, where microsporangia develop, carpel contains ovary where ovules are found. Ovules contain the megasporangia

Pollinators

What helps fertilization by bringing the male gamete to the female egg (Flowers with different scents, shapes, and colors attract different ones)

Fruit

Structure derived from ovary and encloses one or more seeds (tissues are nutritious and brightly colored, makes efficient seed dispersal possible)

Plant form requirements

Light, carbon dioxide, water, nutrients

Shoot system (above ground)

Harvests light and carbon dioxide from atmosphere to produce sugars

Root system (below ground)

Anchors plant and takes in water and nutrients from soil, storage

Importance of high surface area/volume

More contact with the environment meaning there is higher ability to absorb nutrients like photons (leaves) and water (roots)

Phenotypic plasticity

Changes in an organisms phenotype depending on environmental conditions

Example of phenotypic plasticity

Oak tree leaves vary depending on the amount of sunlight they are exposed to

Nitrogen fixation (Important to symbiotic bacteria)

The plant provides sugars from photosynthesis that are utilized by the nitrogen fixing microorganism. The plant provides the microorganism a place to live

Parasitic plant

Plants that live on the host, obtaining water or nutrients and reduce the host’s fitness. Make their own carbohydrates during photosynthesis using carnivory to supplement nitrogen available in the environment

Carnivorous plants

A plant that traps insects and other animals: they kill their prey and absorb the nutrients

Multicellularity

An organism that consists of more than one cell

Heterotrophs

An organism that eats plants and animals (cannot make its own food)

Motility

The ability of an organism to move or get around

Bilateral symmetry

Left and right sides

Cephalization

Concentration of sensory organs in head region. Great deal of diversity of sensory abilities and structures among the animals

Radial symmetry

Symmetry around central axis (ex: sea star)

Coelom

An enclosed, fluid-filled body cavity between the tubes: provides space for oxygen and nutrients to circulate, enables the internal organs to move independently of each other

Acoelomates

Lack body cavity

Pseudocoelomates

“False” body cavity derived from both endoderm and mesoderm, still functional

Coelomates

Arises completely within mesoderm - body cavity and internal organs aligned with mesoderm, tissue holds organs in place, allowing motion

Detritivores

Feed on dead organic matter

Herbivores

Feed on plants or algae

Carnivores

Feed on animals

Omnivores

Feed on a combination of plants, animals, fungi, protists, archaea, and/or bacteria

Diversification of feeding strategies

Suspension feeders, deposit feeders, fluid feeders, mass feeders

Asexual reproduction

New offspring are produced by one parent (budding or parthenogenesis)

External fertilization

Occurs in the environment, extremely common in aquatic species, females lay eggs onto a substrate or release them into open water, males shed swimming sperm on or near the eggs or into open water

Internal fertilization

Fertilization that occurs within the female’s body

Viviparous

“Live-bearing species”

Oviparous

“Egg-bearing species”

Ovoviviparous

“Egg-live-bearing species”

Protostomes

Mouth developed first

Adaptations in transition from water to land

High surface area/volume, cuticle, some have spiracles for gas exchange, desiccation-resistant eggs

Traits of anthropods

Most abundant animals on earth, segmented bodies, exoskeleton, jointed appendages

Traits that make insects a diverse group

Wings, eat plants, co-evolution with angiosperms (flowering plants)

Deuterostomes

Developed anus first (three phyla)

Echinoderms

Organisms with pharyngeal gill slits

Traits of vertebrates

Vertebrae and cranium

Ray-fin fish

Dominant vertebrate group

Amphibians, reptiles, mammals

Key tetrapod groups

Key adaptations for vertebrates

Jaws, lungs, lobbed fins to limbs (tetrapods), amniotic egg, scales, feathers, placenta, fur, lactation, parental care

Types of mammals

Monotremes, marsupials, eutherians (placental)

Monotremes

Five known species that lay eggs and have no teeth

Marsupials

Embryo continues development in pouch, mainly in Australia, one species in North America (opossum)

Eutherians (placental mammals)

Most mammals, after development period (gestation), embryo emerges from mother’s body

Hemichordate

Dorsal hollow nerve chord

Chordate

Notochord; muscular post-anal tail