Biology - Unit 1 test

Animal characteristics

* Multicellular
* Eukaryotic with no cell walls
* Heterotrophs (consumers)
* Aerobic
* Most are mobile
* Have a nervous system to respond to their environment
* Locomotion relates to ability to obtain food
* Common ancestor of animals was probably a flagellated protist, 700 million years ago.

The three types of layers

* Ectoderm


* Endoderm
* Mesoderm

Ectoderm

Outer layer, forms skin and nervous system

Endoderm

Inner layer, gut

Mesoderm

Middle layer, circulatory, reproductive, excretory, muscular systems

Types of symmetry

* Radial symmetry
* Bilateral symmetry

Radial symmetry

* Numerous lines of symmetry, i.e. starfish


* Lacks one dominant region therefore slow movement

Bilateral symmetry

True head region, these animals move in one direction (forward)

Cephalization

Anterior concentration of nerves (sense organs)

Coelom

* Fluid-filled space between body gut and body wall
* Contains and protects internal organs
* Lined by the peritoneum (covers organs & holds them in place)

Acoelomates

Animals have three cell layers with a digestive tract but no body cavities.

Pseudocoelomates

Animals with a fluid-filled body cavity partly lined with mesoderm.

Coelomates

Animals with a body cavity completely surrounded by mesoderm.

Exoskeleton

A hard covering that supports and protects the bodies of some types of animals

Endoskeleton

An internal skeleton, such as the bony or cartilaginous skeleton of animals.

Advantages of an exoskeleton

* Provides protection against predators and strength against prey
* Used as a home

Disadvantages of an exoskeleton

* Limited Movement
* Exoskeleton cannot grow

Advantages of an endoskeleton

* Provides support for the body
* Protects internal organs
* Allows for movement

Disadvantages of an endoskeleton

* Vulnerable to the external environment
* Susceptible to disease

Swim bladder

A gas-filled organ in fish. Its primary function is to float.

Metamorphosis

Changes from egg to adult form

Amniotic egg

fluid filled sac to protect embryo

Phylum Porifera

Sponges

* Asymmetrical
* Most are marine but some freshwater
* Sessile as adults but larvae is motile

Phylum Cnidaria

Sponges

* Have nematocysts – stinging cells that inject toxins into prey
* Hydras, anemones, jellyfish and coral
* Radial symmetry

Phylum Platyhelminthes

Tapeworm

Phylum Nematoda

Hookworm

Phylum Annelida

Earthworm

Phylum Mollusca

Snails

* Three main unsegmented body parts: a foot, a visceral mass, a mantle
* Soft bodies, hard Shells (may be reduced or absent)
* Most have a radula - rasping tongue like organs with hard teeth to scrape or cut food

Agnathans

Lamprey. hagfish:

* No jaws
* Parasite fish
* They have gill slits but no paired appendages

Chondrichthyes

Sharks, rays

* Their skeletons are made of cartilage
* Their fins are often thick.
* Reproduction uses internal fertilization.

Actinopterygii

Most common fish

* Their skeletons are bony.
* Most have a swim bladder


* Most species use external fertilization.

Amphibia

Frogs, salamanders

* Most have an aquatic larval stage with gills
* Adults are tetrapods having four limbs adapted for moving on land
* Most species use external fertilization

Reptilia

Snakes, lizards

* Most are terrestrial tetrapods with dry scaly skin.
* They use internal fertilization.
* They have amniotic eggs with soft shells

Aves

Birds

* They are tetrapods with forelimbs modified as wings.
* Most species are capable of flight.
* They have feathers.

Mammalia

Mammals

* They are tetrapods and have hair.
* They nurse their young with milk produced in mammary glands
* They are warm blooded (endothermic)

Phylum Echinodermata

Sand dollar

Phylum Arthropoda

Ants

Species diversity

A measure of diversity that takes into account the quantity and variety of each species present. Ex: Different breeds of dogs

Heterotroph

An organism that obtains energy by consuming other dead or living organisms.

Autotroph

An organism that uses a source of energy (sun) to produce nutrients.

Taxonomy

The scientific study of how living things are classified.

Taxon

Groups of organization into which organisms are classified.

Dichotomous Key

A method of identification when groups of organisms are divided into two categories.

Binomial nomenclature

The formal system of naming species where each species is assigned a genus name followed by a specific name.

8 major levels of classification

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species Dumb King Phillip Called Out For Good Soup

Phylogeny

The study of the evolutionary relatedness between, and among, species.

Phylogenetic tree

A branching diagram used to show evolutionary relationships between different species or groups.

Clades

A piece of a phylogeny that includes a single common ancestor and all its descendents.

Prokaryotes

* Unicellular
* Do NOT have membrane-bound organelles
* Ex: bacteria

Eukaryotes

* Unicellular and multicellular
* Have organelles

Conjugation

A temporary union of two organisms for the purpose of DNA transfer. (sexual)

* One bacterial cell passes a copy of a plasmid to a nearby bacterial cell through a hollow pilus

Binary fission

A form of asexual reproduction in single-celled organisms when one cell divides into two cells

* Parent cell splits into two daughter cells.
* Each daughter cells receive an exact copy of the genetic material
* Replicate quickly therefore many mutations occur

Budding

* In budding, the individual yeast cell acts like tiny hypha.
* The nucleus divides
* A septum forms between the two nuclei
* A small daughter cell is formed or the side of the original yeast

Bacteria structure

* DNA loose in cytoplasm - no nucleus.
* Ribosomes are also scattered in the cytoplasm.
* Many have one or more plasmids.
* Peptidoglycan - protective coating ONLY on bacteria
* Makes up its cell wall.
* Bacteria may have an outer capsule for protection

Virus structure

* Capsid
* DNA/RNA

Organisms that reproduce asexually

Some plants, some fungi, and many microorganisms.

Organisms that reproduce sexually

Animals and humans.

The three domains are

Bacteria, Archaea, Eukarya

Nonpathogens

A microorganism that is not capable of causing a disease

Pathogens

A microorganism that cause disease

Capsid

Protein coat surrounding a virus

Lysis

The bursting of a cell

Lytic cycle

* Virus is active
* Symptoms occur
* Viral reproduction occurs
* Cells burst

Lysogenic

* Virus is dormant
* No symptoms
* Reproduction does not immediately occur
* These latent viruses may remain inactive for years

Bacteriophage

Species that infect bacteria

Vaccine

* A weakened form of a virus is injected
* This triggers an immune response but not illness
* The 'antibodies' are stored in memory in case of contact with the true form of the virus

Capsule

* Covers the cell wall in prokaryotes
* Reduces water loss
* Resists high temp
* Resists antibiotics and high viruses

Endospore

* A small, rounded, thick-walled, resting cell that forms inside a bacterial cell
* Metabolically inactive
* Highly resistant to harsh conditions for long periods

Obligate aerobes

Microorganisms that need oxygen to survive

Facultative aerobe

Uses oxygen when it is present but lives anaerobically when oxygen is absent

Obligate anaerobe

Microorganisms killed by oxygen

Archaebacteria

A group of microorganisms whose cell walls do not contain peptidoglycan and that live in extremely harsh environments.

Antibiotic

A chemical that kills bacteria or slows their growth without harming body cells by stopping the cell wall from building

Plasmid

A small loop of DNA that carries genes that often provide an advantage to the cell

Cocci

Spherical

Bacilli

Rods

Spirilla

Spiral

Diplo

Double

Strepto

Chains

Staphylo

Clusters

When do we use antibiotics?

Antibiotics are only needed for treating certain infections caused by bacteria

When do we use vaccines?

When people are at risk of contracting a diseas

What are protists?

* Most diverse kingdom (odds and ends)
* Includes very small, single-celled, mobile organisms such as amoeba and very large, multicellular, stationary organisms such as large green kelp.

Protist Characteristics

* Eukaryotes
* Most unicellular, few multicellular
* Some are motile
* Some have cell walls
* NOT bacteria, fungi, plants or animals

Plant-like protists

* Spirogyra – long green strands
* Volvox – green spheres
* ==Algae== – green rods
* Diatoms – brown & shiny

Animal-like protists

* Stentor – small, greenish
* Euglena – tiny, green rods
* ==Amoeba== – larger blobs
* Paramecium – oval shaped, cilia
* Mixed protozoa – lots of neat ones!

Fungus-like protists

* Cellular slime molds
* Acellular slime molds
* Water molds

Cuticle

To reduce water loss

Stomata

To regulate gas exchange and reduce water loss

Xylem and phloem

* Specialized for the transportation of water and nutrients
* Allows plants to grow to great heights
* Lignin (in vascular tissue) provides the strength of wood

Bryophytes

* Includes mosses, liverworts and hornworts.
* Do NOT have specialized conductive tissues or true leaves, roots or seeds
* Only a few centimeters in height
* Have ‘rhizoids’ (primitive roots)

Lycophytes and Pterophytes

* Development of vascular tissue = xylem and phloem
* Seedless plants
* Simple roots
* Simple stems = rhizomes
* Fronds (a fern leaf)

Gymnosperms

* Conifers (ex. Pines, spruces, cedars, etc.)
* Produce unprotected seeds in cone-like structures
* Leaves are thin and needlelike and are covered by a hard waxy cuticle
* Roots extend over wide surface area → this anchors the tree and prevents erosion

Angiosperms

* More than 90% of all modern plant species
* Flowers produce both pollen and eggs
* In the female part of the flower, the eggs are enclosed in an ovary
* After fertilization, seeds in the ovary, and the outer tissues of the ovary become a fruit.

Rhizome

Underground plant stem capable of producing the shoot and root systems of a new plant

Frond

The leaves of ferns

Fungus structure

* Its reproductive structure grows out of the ground.
* Most of its body often remains hidden below the ground.

Hyphae

* Hyphae are often microscopically thin
* They consist of long tubes of cytoplasm containing many nuclei which may be separated into compartments by cell walls called septa.
* The cytoplasm is contained by a cell wall made of chitin – a complex chemical
* Hyphae also form the “fuzz” often associated with mold.

Mycelium

A network of fungal threads or hyphae

Chitin

A complex chemical that is used to make cell walls in fungus