Glossary- 17- (Evolution) Flashcards Preview

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Flashcards in Glossary- 17- (Evolution) Deck (58):
1

Gametophyte

The haploid phase of the life history. Produces the male and female gametes.

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Heteromorphic

Refers to algal or plant life histories in which the haploid gametophytic and diploid sporophytic phases are different (often very different) in size and structure.

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Phragmoplast

The mitotic process in higher-plant organisms in which the nuclear envelope is non-persistent during division, and the mitotic spindle remains intact, keeping the daughter nuclei relatively far apart during cell-plate formation.

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Phycoplast

The mitotic process in algal organisms in which the nuclear envelope is persistent throughout division, and the collapse of the mitotic spindle results in the close proximity of the daughter nuclei during cell-plate formation.

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Sporophyte

The diploid phase of the life history. Meiosis takes place here within sporangia to produce haploid spores in plants that have an alternation of generations

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Tracheids

The water-conducting cells of plants, secondarily thickened and dead when functioning. They link up to form conducting channels in the vascular cylinder.

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Vascular System

The water- and food-conducting tissues; consists of xylem and phloem

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Xylem

Water-conducting tissue consisting of tracheids and associated strengthening cells (fibres) and parenchyma

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Caenozoic Era

The time of flowering plant dominance. From 65 million years ago to the present day.

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Gondwana

An ancient land mass that comprised the continents of Australia, Antarctica, India, South America and Africa.
It began to break up during the Cretaceous and the southern conti8nents gradually moved in their current positions

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Heterosporous

A plant that produces two types of meiotic spore. The smaller microspore gives rise to the “male-” or microgametophyte that produces sperm; the larger megaspore gives rise to the “female-” or megagametophyte that produces the egg cell.

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Homosporous

A plant that produces only one type of meiotic spore. The spores germinating to produce only one type of gametophytes on which antheridia and archegonia are produced.

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Mesozoic Era

Time of cycad and conifer dominance (and dinosaurs). 250-65 million years ago.

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Carpel

A "female" part of a flower. It consists of a stigma (pollen receptive area) that is elevated on a style above the ovary (which contains ovules)

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Endosperm

Triploid tissue resulting from the fusion of a sperm cell with the two polar nuclei of the megagametophyte. It is the food reserve for the developing embryo.

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Fertilization

The fusion of sperm and egg (or polar )cells

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Pollination

The transfer of pollen from anthers to the stigma

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Stamen

A "male" part of a flower. It consists of an anther (pollen sac) borne on a sterile filament (stalk)

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Germ layer

Layer of cells in embryo that develops into body features

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Diploblastic

Two germ layers

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Triploblastic

Three germ layers

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Coelom

Body cavity within the mesoderm

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Blastopore

Opening in the blastula during initial cell development

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Protostome

Blastopore become mouth, anus either forms later or at same time as mouth

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Deuterostome

Blastopore becomes anus, mouth develops later

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Segmented

True segmentation is serial repetition of functional units in a body plan. Mesoderm and ectoderm are divided into segments; the endoderm is unsegmented.

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Exopterygotes

Develop through series of larval stages or nymphs

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Moulting = Ecdysis

Shedding the exoderm or exoskeleton between each larval or nymphal stage

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Mantle

Dorsal body wall of mollusc which often forms shell

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Mantle cavity

In molluscs, the space between mantle and main body where gills (or lungs in terrestrial snails) are found

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Radula

Specialised mouthparts in molluscs

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spicules

Spikey structures surrounding the mantle in chitons

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Pedicellariae

Modified spines with claws capable of movement in echinoderms

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Notochord

A stiff rod of mesoderm found next to the nerve chord in all chordate embryos (and some adults)

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Detrivores

Species that eat dead and/or decaying organic matter

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Tetrapod

Species with four feet or leg-like appendages

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Archosaurs

Evolutionary origin of bird species

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Prototheria

Group which the monotremes belong – egg laying mammals (echidna and platypus)

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Metatheria

Marcupials, carry developing young in a pouch

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Eutheria

Placental mammals

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Gestation

Pregnancy

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Digitigrade

Mammals that walk on the tips of the feet (on their toes)

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Plantigrade

Mammals that walk on their entire feet right up to the heel, including primates, bears and hedgehogs

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Bipedal

Walking on two legs

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Ecology

The way in which organisms interact with their environment, including other organisms

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Evolution

The change in inherited traits found in populations of individuals

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Ecosystem

The environment, its physical properties and all the organisms and communities found there

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Community

Any group of species that live in the same place and potentially (or actually) interact with each other

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Population

A group of individuals of the same species

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Symbiosis

When two species interact closely together in a way which is beneficial to one or both

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Mutualism

When two species interact closely and both species benefit

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Obligate symbiosis

Species have to live together or they will not survive

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Facultative symbiosis

Species can live together but can also survive alone for at least part of their life

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Commensalism

When two species interact closely and one species benefits; the other appears unharmed

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Ecto- and Endoparasites

Species of parasite where at least part of the lifecycle requires the parasite to live outside (ectoparasite) or inside (endoparasite) a host

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Evolutionary Arms Race

When individual evolves a trait that provides an advantage, other individuals must evolve a counter trait to survive or reproduce. Because there has been counter evolution, the first individual must further evolve to stay ahead of the survival or reproductive game. These can be likened to the biological version of weapons arms races.

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Intra-specific competition

Competition between individuals in same species

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Inter-specific competition

Competition between individuals in different species