Key Concepts in Evolution and Plant Biology

anaerobic organisms

occur in the absence of oxygen or do not require oxygen to live. For example, anaerobic bacteria produce energy from food molecules without the presence of oxygen.

analogy or homoplasy

When similar characteristics occur because of environmental constraints and not due to a close evolutionary relationship, it is an

Apical Meristems

Embryonic plant tissue in the tips of roots and in the buds of shoots that supplies cells for the plant to grow in length.

Autotrophic organisms

organisms that convert solar energy into chemical energy are called phototrophs, and they appeared within one billion years of the formation of Earth.

basal taxon

a lineage that evolved early from the root that remains unbranched

binomial nomenclature

Scientists generally refer to an organism only by its genus and species, which is its two-word scientific name.

Biofactories

produce various chemicals, including insulin and antibiotics

biofilm

A surface-coating colony of one or more species of prokaryotes that engage in metabolic cooperation.

Biological nitrogen fixation

conversion of atmospheric nitrogen into ammonia exclusively carried out by prokaryotes

Bioremediation

The use of living organisms to detoxify and restore polluted and degraded ecosystems

body plan

In animals, a set of morphological and developmental traits that are integrated into a functional whole—the living animal.

branch point

represents the divergence of two species

Cambrian explosion

A burst of evolutionary origins when most of the major body plans of animals appeared in a relatively brief time in geologic history; recorded in the fossil record about 545 to 525 million years ago.

cell wall

functions as a protective layer, and it is responsible for the organism's shape.

Characteristics of Protists

• Classified into the Domain Eukarya and the Kingdom Protista • Complexity and diversity of protists makes them difficult to classify • Most (not all) are unicellular • Protists range from microscopic, single-celled organisms to the enormous, multicellular kelps.

Charophytes

green algae that are the closest relatives of land plants

Chlorophytes

part of green algae; live in fresh water but many are marine inhabitants; some live in damp soil, other on glaciers and snowfields; some live symbiotically with fungi to form lichens

clades

A group of species that includes an ancestral species and all its descendants.

cladistics

How do scientists construct phylogenetic trees? After they sort the homologous and analogous traits, scientists often organize the homologous traits using this system.

Conidiospores

asexual, unicellular or multicellular spores that are released directly from the tip or side of the hypha.

conjugation

DNA is transferred from one prokaryote to another by means of a pilus, which brings the organisms into contact with one another, and provides a channel for transfer of DNA.

Coronacollina acula

sponge-like fossils that date back as far as 560 million years, and are believed to show the existence of hard body parts and spicules.

accessory pigments

energy absorbing plant pigments other than chlorophyll

Cretaceous period

Period from 144 million to 66 million years ago. Continents move toward their present-day positions as South America splits from Africa.

cristae

The mitochondrial inner membrane is extensive and involves substantial infoldings.

Cryogenian period

geologic period (850-630 million years ago) characterized by a very cold global climate.

cuticle

A waxy covering on the surface of stems and leaves that acts as an adaptation to prevent desiccation in terrestrial plants.

cyanobacteria

also known as 'blue-green algae,' evolved from these simple phototrophs at least one billion years later.

embryophytes

Another name for land plants, recognizing that land plants share the common derived trait of multicellular, dependent embryos.

Homothallic

Organism with both mating types present.

Heterothallic

Organism with only one mating type present.

Ordovician Period

Era when plant life first appeared on land.

Embryophytes

Common name for land plants with multicellular embryos.

Embryonic Development

Process from fertilization to recognizable fetus.

Zygote

Fertilized egg from sperm and egg fusion.

Cleavage

Cell division of zygote forming blastomeres.

Morula

Solid ball of cells formed during cleavage.

Blastulation

Formation of blastocyst with inner cell mass.

Gastrulation

Formation of three primary germ layers.

Ectoderm

Outer germ layer developing skin and nervous system.

Mesoderm

Middle germ layer forming muscles and bones.

Endoderm

Innermost germ layer developing digestive systems.

Neurulation

Formation of neural tube for central nervous system.

Organogenesis

Development of organs from germ layers.

Endospores

Protective spores formed inside bacterial cells.

Endosymbiosis

Process forming eukaryotic cells from prokaryotes.

Endosymbiotic Theory

Theory of eukaryotes evolving from prokaryotic symbiosis.

Anoxic Atmosphere

Early Earth atmosphere lacking molecular oxygen.

Colonization of Land

First land plants appeared around 470 million years ago.

Vascular Plants

Plants with xylem and phloem for transport.

Seed Plants

Gymnosperms emerged around 360 million years ago.

Angiosperms

Flowering plants evolved around 140 million years ago.

Extracellular Matrix

Substance embedding animal tissue cells.

Extremophiles

Archaea living in extreme environmental conditions.

Facultative Anaerobes

Organisms using fermentation or respiration for ATP.

Flagella

Whiplike tails aiding movement in single-celled organisms.

Fungal Nutrition

Fungi are heterotrophic decomposers or parasites.

Gametangia

Protective jacket for gametes in primitive plants.

Germ Layers

Three layers forming tissues and organs in animals.

Haplodiplontic

Life cycle alternating between haploid and diploid stages.

Haustoria

Parasitic hyphae invading living cells.

Homeobox (Hox) Genes

Genes regulating segmental organization in embryos.

Homology

Similarity due to common ancestry.

Ediacaran Biota

Early animal life evolved from protists.

Chlorarachniophytes

Organisms with chloroplasts derived from green algae.

Fungal Reproduction

Fungi reproduce sexually and/or asexually.

Growth of Fungi

Fungal growth accelerates when immune system is depressed.

Eukaryotic Chromosomes

Linear DNA coiled around histones.

Chromosome

Linear DNA molecule coiled around histones.

Cretaceous Period

Era marked by dominance of flowering plants.

Pollinating Insects

Insects that help fertilize flowering plants.

Permian Extinction

Mass extinction event leading to new plant adaptations.

Fungi Nutrient Acquisition

Release enzymes, absorb resultant nutrient molecules.

Mosses

Intermediate stage in terrestrial plant adaptation.

Kingdom Fungi

Contains approximately 80,000 species.

Hydrothermal Vent

Ocean water heated by magma, rises through cracks.

Hyphae

Branching, threadlike tubes of multicellular fungi.

Diplontic Life Cycle

Only haploid cells are gametes.

Haplontic Life Cycle

Only diploid cell is the zygote.

Prokaryotic Compartmentalization

No membrane-bounded organelles or internal compartments.

Koch's Postulates

Experimental steps linking microbe to disease.

Land Plant Adaptations

Includes cuticle, stomata, vascular tissue, roots.

Phylogenetic Trees Limitations

Branch length lacks time association.

Lycophytes

Includes club mosses, spike mosses, and quillworts.

Maximum Parsimony

Investigate simplest explanation first.

Mesozoic Era

245-144 million years ago; rise of mammals.

Metabolic Diversity

Bacteria utilize various organic/inorganic energy sources.

Microbial Mats

Multi-layered sheets of prokaryotes, mostly bacteria.

Mitochondria

Organelle for respiration and energy production.

Mixotrophs

Organisms combining photosynthesis and heterotrophy.

Molecular Systematics

Use of molecular data in taxonomy.

Monophyletic Group

Includes a single ancestral species and descendants.

Diploid Organisms

Most animals; body cells are diploid.

Mycology

Study of fungi.

Mycorrhizae

Fungus associated with plant roots.

N-acetyl-D-glucosamine

Structural component in arthropod exoskeletons.

Nitrogen Fixation Equation

N2 + 16ATP + 8e− + 8H+ → 2NH3.

Nodules

Roots bumps housing nitrogen-fixing bacteria.

Non-Vascular Plants

Plants lacking vascular tissue for transport.

Nucleoid

Non-membrane-bounded DNA region in prokaryotes.