Bio 125 CH 27

The opisthokonts share the possession of . . .

a single posterior flagellum in flagellated cells like sperm cells

Archaeplastida

the plants arose within this domain

Opisthokonta

the animals and fungi arose within this domain

Define heterotrophic

organisms that require a source of food, ingesting other living or dead organisms

Define autotrophic

organisms that synthesize their own nutrients through photosynthesis

The typical life cycle in animals is . . .

diplontic, you, the diploid state is multicellular, whereas the haploid state is gametic, such as sperm or egg

In animals whose life histories include several to multiple body forms . . .

all body forms are diploid

Define body plan

the morphology of an animal, determined by developmental cues

How does movement happen?

muscle tissue attached to supportive structures like bone or chitin, and is coordinated by neural communication

How does animal senses’ work?

nerve tissues and muscle tissues has resulted in animals’ unique ability to rapidly sense and respond to changes in their environment, this allows animals to survive in environments where they must compete with other species to meet their nutritional demands

How do animals differ from other major multicellular eukaryotes, plants and fungi?

cells don't have cell walls, cells of animal tissues may be embedded in an extracellular matrix, mature bone cells reside within a mineralized organic matrix secreted by the cells

Define extracellular matrix

also called the intercellular matrix, is a network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells

In vertebrates what does bone tissue do?

it is a type of connective tissue that supports the entire body structure, the complex bodies and activities of vertebrates demand such supportive tissues

Define epithelial tissue

a thin, continuous, protective layer of cells with little extracellular matrix, also includes the epidermis of the integument, the lining of the digestive tract and trachea, as well as the layers of cells that make up the ducts of the liver and glands of advanced animals

What does epithelial tissue do?

both covers and protects external and internal body surfaces, and may also have secretory functions

What allows animal diversity?

the differentiation and specialization of tissues

What are the monophyletic clades of the animal kingdom?

Parazoa or Porifera, Placozoa, Cnidaria, Ctenophora, and Bilateria

What are porifera/ parazoa?

sponges, have nearly two dozen cell types

What are placozoa?

tiny parasitic creatures that resemble multicellular amoebae, only have four cell types

What clades do not have specialized tissues derived from germ layers of the embryo although they do possess specialized cells that act functionally like tissues?

placozoa and parazoa

Ctenophores are only distantly related to the . . .

cnidarians

What are the eumetazoa?

basal animal clade as a sister group of the porifera, also known as the true animals

What does it mean to be a diploid organism?

their body, somatic, cells are diploid and haploid reproductive, gamete, cells are produced through meiosis

Which organisms undergo asexual reproduction?

cnidarians, flatworms, roundworms, sea stars and sea anemones

What happens during sexual reproduction?

the haploid gametes of the male and female individuals of a species combine in a process called fertilization, typically both male and female gametes are required with the small, motile male sperm fertilizes the typically much larger, sessile female egg, this process produces a diploid fertilized egg called a zygote

Define fragmentation and budding

part of a parent individual can separate and grow into a new individual, produces genetically identical offspring, which would appear to be disadvantageous from the perspective of evolutionary adaptability, simply because of the potential buildup of deleterious mutations

Define parthenogenesis and what it does

asexual reproduction without fertilization where the embryo develops directly, the development of an embryo from an unfertilized egg cell, only females produce parthenogenetic offspring

Define haplodiploidy

a sex-determination system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid

Define diploid

both maternal and paternal chromosomes

Define haploid

only maternal chromosomes

What is the process when a zygote progresses?

the primary germ layers ectoderm, endoderm, and mesoderm are established and reorganize to form an embryo, animal tissues begin to specialize and organize into organs and organ systems, determining their future morphology and physiology

Define cleavage

the division of cells in the early development of the embryo, following fertilization but before amniogenesis, contains no cell growth

Define blastomere

a type of cell produced by cell division, resulting from subdivision of the material of the egg

Define blastula

an early embryonic stage characterized by a hollow, spherical structure, only hollow in invertebrates whose eggs have relatively small amounts of yolk

What happens to the yolky egg of a vertebrate?

the yolk remains undivided, with most cells forming an embryonic layer on the surface of the yolk which serve as food for the developing embryo

Define gastrulation

an early developmental process in which an embryo transforms from a one-dimensional layer of epithelial cells, a blastula, and reorganizes into a structure called a gastrula

What does gastrulation result in?

the formation of the primitive gut, archenteron or digestive cavity, and the formation of the embryonic germ layers

Define archenteron

also called the gastrocoel, is the internal cavity formed in the gastrulation stage in early embryonic development that becomes the cavity of the primitive gut

Define organogenesis

germ layers are programmed to develop into certain tissue types, organs, and organ systems during this process

How many layers does a diploblastic organism have?

two germ layers, endoderm and ectoderm

What does the endoderm do?

forms the wall of the digestive tract

What does the ectoderm do?

covers the surface of the animal

Define incomplete metamorphosis

the young resemble wingless adults, but gradually produce larger and larger wing buds during successive molts, until finally producing functional wings and sex organs during the last molt

Define complete metamorphosis

the embryo develops into one or more feeding larval stages that may differ greatly in structure and function from the adult, the adult body then develops from one or more regions of larval tissue, the larva and the adult may have different diets, limiting competition for food between them

What do incomplete and complete metamorphosis have in common?

the series of developmental stages of the embryo remains largely the same for most members of the animal kingdom

Define homeotic genes

genes that determine animal structure and they contain DNA sequences called homeoboxes

Who were Christiane Nüsslein-Volhard and Eric Wieschaus?

introduced mutated genes into fruit flies and observed changes to the flies' bodies under microscopes, they were able to identify specific changes, such as different numbers of body segments, based on mutations of specific genes, therefore showing which genes controlled aspects of development

Define homeoboxes

a DNA sequence, around 180 base pairs long, that regulates large-scale anatomical features in the early stages of embryonic development

What could a homeobox change?

large-scale anatomical features of the full-grown organism

Define hox genes

a subset of homeobox genes, is responsible for determining the general body plan, such as the number of body segments of an animal, the number and placement of appendages, and animal head-tail directionality, the order of the genes reflects the anterior-posterior axis of the animal's body

Why are hox genes so important?

they serve as master control genes that can turn on or off large numbers of other genes, they do this by encoding transcription factors that control the expression of numerous other genes, are remarkably similar across most animals because of their presence in a common ancestor

Why has animal body complexity increased?

hox genes have undergone at least two and perhaps as many as four duplication events during animal evolution, with the additional genes allowing for more complex body types to evolve

How many sets of hox genes do vertebrates have?

four or more

How many sets of hox genes do invertebrates have?

one set

How are animals classified?

body plan and developmental pathway

What is the major feature of a body plan?

its symmetry, how the body parts are distributed along the major body axis, symmetrical animals can be divided into roughly equivalent halves along at least one axis

What are the developmental characteristics?

the number of germ tissue layers formed during development, the origin of the mouth and anus, the presence or absence of an internal body cavity, and other features of embryological development, such as larval types or whether or not periods of growth are interspersed with molting

Asymmetry is seen in which clades?

parazoa and placozoa, the ancestral fossils of the parazoa apparently exhibited bilateral symmetry

Radial or biradial symmetry is seen in which clades?

cnidaria

Rotational symmetry is seen in which clades?

ctenophores

Bilateral symmetry is seen in which clades?

bilateria however the Echinodermata are bilateral as larvae and metamorphose secondarily into radial adults

Define radial symmetry and how it is determined

the arrangement of body parts around a central axis, results in animals having top and bottom surfaces but no left and right sides, nor front or back with the sides being mirror images of each other, a radially symmetrical animal is divided in any direction along the oral/aboral axis

Define aboral

relating to or denoting the side or end that is furthest from the mouth, especially in animals that lack clear upper and lower sides, the side without a mouth is the aboral side

Define bilateral symmetry

have only a single plane along which the body can be divided into equivalent halves, resulting in right and left halves

Define anterior

the head of an organism

Define posterior

the tail-end of an organism

Define dorsal

the front side of an organism

Define ventral

the backside of an organism

All Eumetazoa except those with secondary radial symmetry are . . .

bilaterally symmetrical

What does the evolution of bilateral symmetry do?

allowed for the formation of anterior and posterior ends promoted a phenomenon called cephalization, which refers to the collection of an organized nervous system at the animal’s anterior end

What is radial symmetry best suited for?

stationary or limited-motion lifestyles

What is bilateral symmetry best suited for?

streamlined and directional motion, in evolutionary terms, this simple form of symmetry promoted active and controlled directional mobility and increased sophistication of resource-seeking and predator-prey relationships

Animals in the phylum Echinodermata display what type of symmetry?

modified radial symmetry as adults, but as we have noted, their larval stages initially exhibit bilateral symmetry until they metamorphose in animals with radial symmetry

What is the symmetry of Echinoderms?

bilaterally symmetrical

The animals that display radial, biradial, or rotational symmetry develop what?

two germ layers, an inner layer, endoderm or mesendoderm, and an outer layer, ectoderm

Define diploblast

two germ layers, have a nonliving middle layer between the endoderm and ectoderm, although individual cells may be distributed through this middle layer, there is no coherent third layer of tissue

Define triploblast

organisms that have three tissue layers

Generally speaking, the endoderm gives rise to the lining of which places?

the digestive tract including the stomach, intestines, liver, and pancreas, as well as to the lining of the trachea, bronchi, and lungs of the respiratory tract, along with a few other structures

What does the ectoderm develop into?

the outer epithelial covering of the body surface, the central nervous system, and a few other structures

Where does the mesoderm form?

between the endoderm and ectoderm in triploblasts

What does the mesoderm do?

layer gives rise to all specialized muscle tissues including the cardiac tissues and muscles of the intestines, connective tissues such as the skeleton and blood cells, and most other visceral organs such as the kidneys and the spleen

Define coelom and what it does

the principal body cavity in most animals, located between the intestinal canal and the body wall, develops from the mesoderm, usually filled with fluid, houses many organs such as the digestive, urinary, and reproductive systems, the heart and lungs, and also contains the major arteries and veins of the circulatory system

In mammals how does the body cavity work?

it is divided into the thoracic cavity, which houses the heart and lungs, and the abdominal cavity, which houses the digestive organs

Define thoracic cavity

body cavity surrounded by the rib cage

What does the thoracic cavity do?

cavity further subdivision produces the pleural cavity and the pericardial cavity

What does the pleural cavity do?

provides space for the lungs to expand during breathing

What does the pericardial cavity do?

provides room for movements of the heart

What has the evolution of the coelom done in terms of function?

it provides cushioning and shock absorption for the major organ systems that it encloses, organs housed within the coelom can grow and move freely, which promotes optimal organ development and placement, also provides space for the diffusion of gases and nutrients, as well as body flexibility, promoting improved animal motility

Define acoelomate and what it entails for the organism

absence of a coelom, their mesoderm region is completely filled with tissue, although they do still have a gut cavity

Define eucoelomate and what it entails for the organism

true coelom, arises entirely within the mesoderm germ layer and is lined by an epithelial membrane

What does the epithelial membrane do in concern to the coelom?

the organs within the coelom, connecting and holding them in position while allowing them some freedom of movement

What is this an image of?

an aceolmate cavity

What is this an image of?

eucoelomate cavity

What is this an image of?

pseudocoelomate cavity

Bilaterally symmetrical, triploblastic eucoelomates can be further divided into two groups based on what?

differences in the origin of the mouth, the classifications are protostome and deuterostome

Define protostome

the mouth develops at the blastopore

Define deuterostome

the mouth develops at the other end of the gut and the anus develops at the site of the blastopore

Define schizocoely and what it does

a process by which some animal embryos develop, the coelom of most protostomes is formed through this process

Define enterocoely

describes both the process by which some animal embryos develop and the origin of the cells involved, the coelom of deuterostomes form through this through the process of pouches that are pinched off from the endoderm tissue with these pouches eventually fuse and expand to fill the space between the gut and the body wall, giving rise to the coelom

Protostomes undergo what?

spiral cleavage