Biology Evolution: Systematics, Life History, and Plant Diversity

What is systematics?

A discipline that tries to understand the history of ancestor-descendant relationships through the reconstruction and study of evolutionary relationships.

What does taxonomy describe?

How we organize organisms.

What is binomial nomenclature?

A naming system developed by Linnaeus in the 1700s, using the format 'Genus species'.

What is phylogeny?

A hypothesis of evolutionary relationships among species.

What do closely related species share?

More similar traits and a more recent common ancestor.

What is convergent evolution?

The evolution of similar traits in different species due to similar habitats.

What are synapomorphies?

Derived characters shared by a clade.

What is a cladogram?

A diagram that depicts the relationships among species based on recent common ancestors.

What is the principle of parsimony?

A hypothesis that suggests the simplest explanation with the fewest assumptions is preferred.

What is a monophyletic group?

A group that includes the most recent common ancestor of the group and all of its descendants.

What is a paraphyletic group?

A group that includes the most recent common ancestor but not all of its descendants.

What is a polyphyletic group?

A group that does not include the most recent common ancestor of all its members.

What are homologous characters?

Characters that are similar because they are inherited from a common ancestor.

What are analogous characters?

Characters that have separate evolutionary origins but serve similar functions.

What is homoplasy?

A character shared by species but not inherited from a common ancestor.

What is the biological species concept (BSC)?

Defines species as groups of interbreeding populations that are reproductively isolated.

What is the phylogenetic species concept (PSC)?

Defines species as a population or set of populations characterized by one or more shared derived characters.

What is the significance of DNA sequence data in systematics?

It allows for the construction of phylogenies due to the large number of characters that can be obtained.

What is the molecular clock?

A concept that DNA and protein sequences evolve at a relatively constant rate over time and among different organisms.

What is the Hadean Eon?

The earliest eon in Earth's history, from 4.6 to 3.8 billion years ago, characterized by the formation of the Earth and the creation of oceans.

How did early oceans form?

From torrential rains that occurred after the Earth's surface cooled and lost capacity to hold water vapor.

What organic molecules were formed in early oceans?

Simple organic, carbon-based molecules like nucleotides and amino acids, energized by lightning and UV radiation.

What are the two hypotheses regarding the origins of life?

1) Extraterrestrial origins (meteors, comets) 2) Reducing atmosphere (high availability of hydrogen gas)

What experiment tested how organic molecules formed in a reducing atmosphere?

The Miller-Urey Experiment

What did the Miller-Urey Experiment simulate to provide energy?

Simulated lightning

When did early life first appear on Earth?

Approximately 3.8 to 4 billion years ago during the Archean eon

What type of organisms were the earliest forms of life?

Prokaryotes, specifically Bacteria and Archaea

What significant event occurred during the Proterozoic Eon?

The Oxygen Revolution, marked by the spread of cyanobacteria

What is endosymbiosis?

A relationship where one organism lives inside another, leading to the origin of mitochondria and chloroplasts

What key evolutionary development occurred around 2 billion years ago?

The first eukaryotic life forms appeared

What major evolutionary event is known as the Cambrian Explosion?

A rapid diversification of life forms that occurred around 500 million years ago

What are the key characteristics of chordates?

Notochord, post-anal tail, gill-like openings, and dorsal hollow nerve cord

What significant evolutionary development occurred during the Devonian period?

The evolution of land animals, specifically tetrapods

What challenges did tetrapods face when moving to land?

Movement, gravity, breathing, desiccation, and reproduction

What important reproductive advancement occurred during the Carboniferous period?

The evolution of amniotic eggs, allowing embryos to survive in a terrestrial environment

What was the primary cause of the mass extinction event at the end of the Permian period?

Volcanic activity leading to drastic environmental changes

What characterized the Mesozoic Era?

The dominance of dinosaurs and the evolution of flowering plants

What significant event occurred at the end of the Cretaceous period?

A mass extinction event that wiped out 60-80% of species, including the dinosaurs

What are the three primary groups of reptiles based on temporal fenestra?

Anapsids (no skull opening), Synapsids (single pair of temporal fenestra), Diapsids (two pairs of temporal fenestra)

What is the significance of the Cenozoic Era?

It marks the era of modern mammals and the evolution of primates and humans

What is a virus?

An infectious microbe consisting of nucleic acid surrounded by a protein coat that cannot replicate alone

What are the two types of genetic material that viruses can have?

DNA or RNA, but not both

What is the function of a virus's capsid?

To protect the viral genetic material

What are retroviruses?

RNA viruses that use reverse transcriptase to convert their RNA into DNA inside the host cell

What are the three main shapes of viruses?

1) Helical capsid 2) Icosahedral capsid 3) Icosahedral head with a helical tail

What is the importance of the amniotic egg?

It allows embryos to develop in a protective environment, facilitating reproduction on land

What major evolutionary transition occurred in the Jurassic period?

The diversification of mammals and the evolution of birds from small bipedal theropods

What significant event marked the transition from the Paleozoic to the Mesozoic Era?

The mass extinction event at the end of the Permian period

What is a helical capsid?

A type of protein structure that encases the genetic material of some viruses.

What surrounds the capsid of a virus?

A phospholipid and protein layer known as the envelope.

What are the stages of virus replication?

Attachment, Penetration, Replication and Transcription, Assembly, Release.

What occurs during the attachment stage of virus replication?

The virus attaches to a specific receptor on the surface of the host cell.

How do viruses penetrate host cells?

By direct fusion with the cell membrane or by being engulfed.

What is the role of the host cell in virus replication?

The host cell's machinery is used to replicate the viral genome.

What happens during the release stage of virus replication?

Newly formed viruses exit the host cell, often killing it in the process.

What are obligate intracellular parasites?

Organisms that can only replicate inside host cells, such as viruses.

What is tissue tropism?

The specificity of a virus for certain types of host cells based on surface receptors.

What is epidemiology in relation to viruses?

The study of viruses in populations.

What is pathogenicity?

The process by which a virus causes disease.

What are the three types of viral infections?

Persistent (latent and chronic), Acute.

What is horizontal gene transfer (HGT)?

The non-sexual movement of genetic information between genomes.

What are the three mechanisms of HGT?

Transformation, Transduction, Conjugation.

What is transformation in HGT?

The uptake of DNA from the environment by a bacterium.

What is transduction in HGT?

The transfer of genetic material mediated by viruses.

What is conjugation in HGT?

The transfer of genetic material from one bacterium to another through direct contact.

What are the main shapes of prokaryotes?

Bacillus (rod-shaped), Coccus (spherical), Spirillum (helix-shaped).

What is the function of the cell envelope in prokaryotes?

Provides shape and protection to the cell.

What is binary fission?

A form of asexual reproduction in prokaryotes where the cell divides into two new cells.

What is the difference between Gram-positive and Gram-negative bacteria?

Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin layer and an outer membrane.

What is the significance of plasmids in prokaryotes?

Plasmids are circular pieces of DNA that can carry genes, such as those for antibiotic resistance.

What are the beneficial roles of prokaryotes?

Fermentation, decomposition, carbon and nitrogen cycling, digestion, and bioremediation.

What are some diseases caused by prokaryotes?

Tuberculosis, Gonorrhea, Chlamydia, Syphilis.

What distinguishes eukaryotes from prokaryotes?

Eukaryotes have complex cell organization, including a nucleus and membrane-bound organelles.

What are protists?

A diverse group of eukaryotes that can be unicellular, colonial, or multicellular.

What forms of locomotion do protists exhibit?

Flagella, cilia, and pseudopodia.

What are the two main types of nutrition in protists?

Heterotrophic (consuming organic material) and autotrophic (producing own food through photosynthesis).

What is a protist?

A single-celled organism that can be either autotrophic or heterotrophic.

What are the characteristics of Excavata protists?

Single-celled organisms with an asymmetric cell shape and a feeding groove.

What are Euglenozoa?

A group of protists that possess mitochondria and include both autotrophic and heterotrophic species.

What defines Diplomonads?

Unicellular protists with two nuclei.

What is the role of Parabasalids?

They have a symbiotic relationship with cellulose and include species like Trichomonas vaginalis.

What are Alveolates?

A group of Chromalveolates characterized by flattened vesicles called alveoli for structural support.

What are Ciliates?

Protists that feature large numbers of cilia arranged in longitudinal rows or spirals around the cell.

What are Dinoflagellates known for?

Photosynthetic protists that can be luminescent and live in aquatic environments.

What is unique about Diatoms?

Photosynthetic, unicellular organisms with unique double shells made of silica.

What adaptations do plants have for terrestrial life?

Adaptations include a waxy cuticle, stomata for gas exchange, and vascular tissues for support.

What is the function of stomata in plants?

Pores on leaves that allow for gas exchange, controlled by guard cells.

What are the two types of vascular tissue in plants?

Xylem, which conducts water and minerals, and phloem, which conducts sucrose and hormones.

What is alternation of generations in plants?

A life cycle that alternates between a multicellular haploid stage (gametophyte) and a multicellular diploid stage (sporophyte).

What are Bryophytes?

Non-tracheophyte plants that lack tracheids and have a dominant gametophyte stage.

What distinguishes Pterophytes?

They are vascular plants with a dominant sporophyte stage and true leaves.

What are Gymnosperms?

Plants with 'naked seeds' that often have needle-like leaves and include four living groups.

What defines Angiosperms?

Plants with ovules enclosed within carpels, which develop into fruit after fertilization.

What is double fertilization in angiosperms?

A process where one sperm fuses with the egg to form a zygote, and another fuses with polar nuclei to form endosperm.

What are the three layers of a fruit's pericarp?

Exocarp, mesocarp, and endocarp.

What is the significance of vascular tissue in plants?

It allows for efficient transport of water and nutrients, enabling larger plant growth.

What is the role of guard cells?

They control the opening and closing of stomata to regulate gas exchange.

What is the main function of the cuticle in plants?

To prevent water loss (desiccation).

What are the two main types of gametangia in Bryophytes?

Archegonia (female) and antheridia (male).

What is the significance of the sporophyte stage in plant evolution?

It became more dominant over time, allowing for increased complexity and protection of the embryo.