biology flashcards

Taxonomy

the identification, description, naming and classification of species

Identification

differences between groups of individuals in specific characters or traits

Description

How species look physically, how they behave and how they are different from others

Nomenclature

The assignment of scientific names to organisms 

Classification

The process of grouping organisms based on their similarities and differences to create a hierarchical system of categories.

Phylogeny

also called an evolutionary tree, represents the revolutionary hypothesis about the relationships in a set of organisms

Tip (in phylogeny)

single terminal branches representing a taxon or individual

Internal node

indicates inferred common ancestor

Root (in phylogeny)

node indicating the shared common ancestor of all tips in the phylogeny

Prokaryote

organisms that lack a nuclear membrane

Eukaryote

Organisms that have a membrane bound nucleus

Chemoheterotrophs

Where energy is derived by ingesting intermediates or building blocks that is incapable of creating on its own

Major transitions

Key events in evolutionary history

Animal

Eukaryotic and multicellular

Endoderm

inner layer

Ectoderm

outer layer

Diploblastic

two layers of cells with tissues but no organs

Triploblastic

tissues developed from three germ layers forming complex organs

Cleavage patterns

There is radial and spiral patterns

Body cavities

refers to the spaces within the body that contain organs

Segmentation

the division of some animal and plant body plans into a series of repetitive segments

What are the three types of germ layers in organisms?

Monoblastic (single layer, no tissues), Diploblastic (two layers, with tissues, no organs), Triploblastic (three layers, forming complex organs).

Why do animals need food?

To function, build, and repair their bodies.

What are the key nutrients animals require?

Oxygen, Carbon, Nitrogen, Water, and trace elements (P, S, Fe).

How do nutrients pass into cells?

By diffusion, which is the movement of solute from high to low concentration until equilibrium is reached.

What adaptations can solve diffusion constraints in organisms?

Folding to increase surface area, changing shape to increase surface area to volume ratio, and having a body cavity (coelom) to increase proximity to fluid reservoirs.

What are the functions of a coelom?

Decreases diffusion distances, acts as a buffer for internal organs, serves as a storage reservoir for nutrients and wastes, and can function as a hydrostatic skeleton.

Which phyla have a coelom?

Annelida, Mollusca, Nematoda, Echinodermata, Chordata, and Arthropoda.

What are the types of transport systems in animals?

Digestive, Excretory, Respiratory, and Circulatory systems.

How do digestive systems differ among animal phyla?

Cnidarians and platyhelminths have blind-ended guts; all others have a complete gut.

What is unique about the excretory systems of platyhelminths?

They have a simple system where cilia draw coelomic fluid to the ends of blind-ended tubules.

How do molluscs and annalids differ in their circulatory systems?

They have a simple heart and an open blood system; annelids have a closed blood system with pumps.

What are the pros of marine life?

Stable environment, iso-osmotic conditions, no desiccation, support for body tissues, and abundant food.

What are the cons of marine life?

Lower oxygen concentration and challenges from wind waves and currents.

What does being sessile mean in marine organisms?

Being fixed in one place, such as sponges, corals, oysters, barnacles, and sea lilies.

What are the advantages of being sessile?

No energy required to stay still or catch food, and having an established living place.

What are the disadvantages of being sessile?

Inability to move if conditions change, being easy targets for predators, and susceptibility to disturbances.

What is the difference between suspension feeding and deposit feeding?

Suspension feeding removes particles from the water column; deposit feeding ingests food from sediment.

What are the characteristics of Porifera (sponges)?

Asymmetrical, porous, monoblastic, no tissues or organs, and hermaphroditic.

What defines Cnidaria?

Diploblastic, no organs, blind gut, and presence of cnidae with nematocysts.

What is the ecological role of Bryozoa?

Suspension feeding using a lophophore.

What are the main features of Platyhelminthes (flatworms)?

Triploblastic, acoelomate, bilateral, with a brain, nerve cords, and a blind gut.

What defines Mollusca?

Triploblastic, coelomate with a mantle cavity, and most have a shell.

What are the ecological roles of Echinodermata?

Suspension feeders, herbivores, and detritivores.

What are the two types of autotrophs in marine environments?

Photosynthetic (e.g., algae) and chemosynthetic (e.g., bacteria at hydrothermal vents).

What is mutualism in symbiosis?

A relationship where both organisms benefit, such as coral and algal cells (zooxanthellae).

What is the morphology of Nematoda?

Triploblastic, coelomate, free-living or parasitic, elongated 'round' worms with no segments.

What are the characteristics of Annelida?

Triploblastic, coelomate, segmented worms with parapodia and sensory structures on their head.

What defines the sub-phylum Chordata?

Presence of a notochord, dorsal nerve cord, and pharyngeal gill slits.

What are the defining characteristics of the phylum Chordate?

Pharyngeal gill slits, notochord, hollow dorsal nerve cord, post-anal tail, and endostyle/thyroid gland.

What does it mean for a chordate to be a deuterostome?

It refers to a developmental process where the anus forms before the mouth during embryonic development.

What distinguishes Craniata from other chordates?

They have a distinct head and a well-developed brain protected by a skull.

What are the key features of Vertebrata?

Jaws, vertebral column, paired fins, and myelinated nerves.

What are Agnatha and what is a characteristic of this group?

they are jawless fishes, characterized by having a mouth but no jaws.

What are the two classes of jawless fishes?

Class Myxini (hagfishes) and Class Petromyzontida (lampreys).

What are the main characteristics of Gnathostomes?

They are jawed fishes, which include Class Chondrichthyes (cartilaginous fish) and Class Actinopterygii (ray-finned fish).

What are the distinguishing features of Class Chondrichthyes?

They are cartilaginous fish with no true bone and teeth (denticles) that are not fused to the jaw.

What is unique about Class Actinopterygii?

They are ray-finned fish with a bony skeleton and 'true' teeth.

What are Sacropterygians and why are they significant?

They are fleshy-finned fishes, including coelacanths and lungfishes, which are closely linked to tetrapods.

What are the four classes traditionally recognized under Tetrapods?

Amphibia, Reptilia, Aves, and Mammalia.

How are Reptilia and Aves classified in modern taxonomy?

They are combined and referred to as Sauropsida.

What are the main characteristics of Amphibia?

Includes frogs, toads, mudpuppies, newts, and caecilians; most require water to reproduce and have aquatic larvae.

What are Amniotes and what are their key adaptations?

They include sauropsids and mammals, characterized by four extra-embryonic membranes and water-resistant skin.

What are the two subclasses of mammals and their reproductive traits?

Protheria (lay eggs) and Theria (bear live young, with Metatheria being marsupials and Eutheria being placentals).

What is the role of mammary glands in mammals?

they secrete milk for young, providing nutrition and antibodies.

What is endothermy in mammals?

It is the ability to regulate body temperature through metabolic heat production.

What are the various feeding strategies exhibited by vertebrates?

Suspension feeders, deposit feeders, detritivores, grazers, gatherers, predators, and parasites.

What ecosystem services do vertebrates provide?

Food source, pollination, seed dispersal, and they act as ecosystem engineers and apex predators.

What is cell metabolism?

The use of energy and the processes of catabolism (breakdown) and anabolism (synthesis) of organic molecules.

What is the significance of metabolic rate in animals?

It defines animal life, produces heat, and is the sum-total of all biochemical reactions occurring in the body.

What are the two types of metabolism and their differences?

Anaerobic metabolism produces energy without oxygen, while aerobic metabolism produces energy with oxygen.

How is metabolic rate measured?

through heat production, oxygen consumption, carbon dioxide production, energy balance, substrate utilisation, and metabolic water production.

What factors determine metabolic rate?

Activity level, body mass, cellular grade, temperature, and locomotion.

What are the three types of animal locomotion?

Aquatic (swimming), terrestrial (walking), and aerial (flying).

Sexual reproduction

uses male and female gametes produced by the gonads and joined during fertilization to form offspring.

Gametes

Male and female reproductive cells (sperm and egg) produced by the gonads and released through gonoducts.

Gonads

Primary sex organs (ovaries and testes) that produce gametes.

Meiosis

Cell division that reduces chromosome number by half (2n to n) and increases genetic diversity through recombination; occurs in the gonads.

Recombination

Exchange of DNA segments during meiosis that creates new combinations of alleles and increases genetic diversity.

Diploid

A cell with two complete sets of chromosomes (2n).

Haploid

A cell with a single set of chromosomes (n).

Mitosis

Division that duplicates DNA and splits a cell into two identical diploid daughter cells; part of the cell cycle in somatic cells.

Somatic cells

Body cells (e.g., fat, blood, skin) that undergo mitosis and are not gametes.

Cell cycle

The ordered sequence of growth and division events a cell undergoes, including interphase and mitosis.

Gametogenesis

Production of gametes in the gonads, involving mitosis and meiosis (spermatogenesis and oogenesis).

Primordial germ cells

Early germ cells that divide to form oogonia or spermatogonia, giving rise to gametes.

Oogonia

Diploid germ cells in females that proliferate by mitosis to form primary oocytes.

Spermatogonia

Diploid germ cells in males that divide by mitosis to produce primary spermatocytes.

Spermatogenesis

Production of sperm from spermatogonia through meiosis and maturation.

Oogenesis

Production of eggs (ova) in females, including formation of primary and secondary oocytes and the ovum.

Primary oocyte

Oocyte that begins meiosis I to give rise to secondary oocyte and first polar body.

Secondary oocyte

Product of meiosis I; upon fertilization completes meiosis II to form ovum and second polar body.

Ovum

Mature egg cell produced after meiosis II.

Polar body

Small byproduct cells produced during oogenesis; usually not fertilized.

Egg maturation

Growth of the oocyte with increased size, organelles, and nutritive materials prior to fertilization.

Zygote

Diploid cell formed by the fusion of haploid gametes; contains a full chromosome set.

Pronuclei

The haploid nuclei of egg and sperm that fuse to form the diploid zygote.

External fertilization

Fertilization that occurs outside the body, often requiring water and specific delivery mechanisms.

Internal fertilization

Fertilization that occurs inside the female body, often involving specialized delivery mechanisms.

Intromittent organ

An organ used to transfer sperm into the female reproductive tract.