bio 112 ch 27&33

which eukaryotic subgroup includes animals?

Opishthokonts

Who is the closest relative to animals? and how do we know that they are the closest?

Choanoflagellates; the evidence is collar cells & genes. They are small; no cell walls; no fossil record

who are the most primitive animals? what cells do they have that is similar to choanoflagellates?

sponges; collar cells (choanocytes)

which were the first animal fossils called? (which era)

Proterozoic era; ediacaran biota

what is the era of dramatic animal diversification called? And what are the animals called?

Paleozoic Era; Cambrian explosion

which type of animals dominated the seas first? Which type of animals invaded land first? Which type of animals invaded land second and which type of animals came to land last?

Vertebrate fishes; Arthropods (Invertebrates); Vertebrates invaded land second (amphibians); Reptile-like amniotes came to land

what were the Mesozoic era animals and which animals came to exist in this era? what marked the end of the Mesozoic era?

Dinosaurs, aquatic reptiles; origin of birds and mammals; cretaceous extinctions

What animals were dominant in the cenozoic era? and which type of dinosaurs came first?

mammals; the first dinosaurs were non-avian

which type of dinosaurs became extinct in the end-Cretaceous era?

non avian dinosaurs

what marked the end of the paleozoic era?

largest mass extinction in the history of the planet!

what are phylogenies based on?

• Analyzing whole genomes

• Morphological Traits

• Ribosomal (rRNA) genes

• Hox genes (control embryonic development and number of appendages)

• Protein coding nuclear genes

• Mitochondrial genes

What are the 4 inferences from the animal phylogenetic tree?

• All animals share a common ancestor

• Sponges are the sister group to all other animals

• Eumetazoa is a clade of animals with tissues

• Most animal phyla belong to the clade Bilateria

what are the three major clades of Bilaterian animals ? (which of them contain vertebrates and which contains only invertebrates?)

• Deutorostomia - contains vertebrates

• Lophotrochozoa

• Ecdysozoa (Both lophotrochozoa and ecdyzosoa contain only invertebrates)

How do endothermic animals generate heat? what about ectothermic? (give examples of animals for each)

Endothermic animals generate heat by metabolism. Ex: Birds & Mammals; Ectothermic obtain heat from external sources. Ex: most invertebrates, amphibians, reptiles, and fishes

Who is more energetically expensive? endothermic or exothermic animals? why?

Endothermic because we are trying to maintain a constant body temperature

Are organisms open or closed systems? what does that mean?

Organisms are open systems; they are in constant exchange of materials with the environment

What are the three things homeostatic processes involve?

• Physical Adaptations

• Behavior

• Physiology

what is bioenergetics? the determination of food an animal needs relates to an animal’s what three things?

Bioenergetics is the flow and transformation of energy in an animal. It determines how much food an animal needs based on:

• An animal’s size

• An animal’s activity

• An animal’s environment

What is basal metabolic rate? Do small animals or large animals have a larger BMR? why?

BMR is the amount of energy an animal uses at a resting state; Smaller animals have a larger BMR because they lose heat much faster than larger animals since they have an increased SA:V ratio than larger animals.

What is torpor? Why do animals do torpor?

What Is Hibernation?

Torpor is a physiological state in which activity is low and metabolism decreases; Animals do this to save energy while avoiding difficult and dangerous situations; Hibernation is a long-term torpor that is an adaptation to winter cold and food scarcity

What is estivation?

Do some animals perform daily torpor, if so who and when?

Estivation is a summer torpor in which animals can survive periods of high temperatures and water scarcity;

Small mammals and birds will perform daily torpor during the coldest parts of the day.

What is a negative feedback loop?

A given stimulus fluctuates above and below a set point; which is detected by a sensor and triggers a response. The response then returns the variable to the set point.

What is a Positive feedback loop? does it contribute to homeostasis in animals?

amplifies a stimulus; positive feedback loops usually do not contribute to homeostasis in animals

Which feedback loop does homeostasis in animals rely on? why?

negative feedback loops; to return a variable to a normal range

Give an example of a negative feedback loop!

Blood glucose regulation:

Food is eaten and digested, blood sugar levels rise»»» pancreas secretes insulin»»» blood sugar is released into cells, and liver cells store glucose as glycogen, Blood sugar levels drop»»» pancreas stops secreting insulin

give an example of a positive feedback loop!

The birth of a human infant:

baby pushes against the cervix »»» nerve impulses are sent to the brain »»» the brain stimulates pituitary to release oxytocin »»» oxytocin causes the uterus to contract!

what is acclimatization? give an example.

Acclimatization is the adjustment to new conditions; An example is an animal moving to a higher altitude than they’re accustomed to. To adjust to the lower oxygen levels, the body will increase the number of red blood cells circulating in the blood to ensure adequate oxygen delivery to the tissues

Why is thermoregulation important?

Our bodies need to maintain a constant body temperature for enzymes to remain efficient and avoid denaturation

What is thermoregulation controlled by?

hypothalamus

What are the four ways heat is exchanged in thermoregulation?

• Convection

• Conduction

• Radiation

• Evaporation

What is another controller of thermoregulation?

the integumentary system (skin, hair, sweat glands)

What are the 5 adaptations that help animals thermoregulate with examples?

1. Insulation - hair

2. Behavioral responses - honeybees huddle together during cold weather to retain heat

3. Circulatory adaptations

• Body temp rises » vasodilation by hypothalamus » sweating (evaporative heat loss)

• Body temp falls » vasoconstriction » blood flow to skin decreases » shivering (warms the body)

4. Cooling by Evaporative Heat Loss

5. Adjusting metabolic heat production (Moving/ Shivering)

What are the 4 Main Types of Multicellular Animal Tissues?

1. Epithelial tissue- lines cavities, open spaces, glands and surfaces

2. Connective tissue- connects different tissues and provides support

3. Muscle tissue - Generates movement (found in skeletal muscle)

4. Nervous tissue - Generates and sends electrical signals

How are epithelial tissues classified? (hint: by what two things) then identify what a single layer and multiple layers is called!

Epithelial tissues are classified by number of layers and the shape of the cell;

simple: means single layer

stratified: means multiple layers

What are the functions of epithelial tissues?

Protection, Secretion, Diffusion, Absorption, Excretion, Filtration

Describe a squamous shaped tissue and identify where it is found depending on number of layers

Flat, irregular round shape;

Simple: lung alveoli (Diffusion), capillaries

stratified: skin, mouth, and vagina (Protection)

Describe a cuboidal shaped tissue and identify where it is found depending on number of layers

Cube shaped, central nucleus;

glands and renal tubules (Filtration)

Describe a Columnar shaped tissue and identify where it is found depending on number of layers

Tall, narrow, and nucleus can be found toward the base or along the cell;

simple: digestive tract (absorption)

pseudostratified: respiratory tract (protection)

Describe a Transitional shaped tissue and identify where it is found depending on number of layers

round (can transition from thick to thin as bladder fills);

stratified: found in urinary bladder

What does connective tissue consist of?

Fibroblasts (produce and secrete fibers) and a ground substance called the non-cellular matrix

What does the ground substance (non-cellular matrix) contain in connective tissue?

some combination of collagen, elastic, or reticular fibers

Where is areolar (loose) connective tissue found?

around blood vessels: anchors epithelia

Where is dense, fibrous connective tissue found ?

irregular: skin

regular: tendons and ligaments

where is cartilage connective tissue found?

Shark skeletons, fetal bones, human ear, intervertebral discs

Where is bone, adipose and blood connective tissue found?

Bone- found in vertebrate skeletons

Adipose- Adipose (fat)

Blood- Blood

What are the three types of muscle tissue?

Skeletal, Smooth and Cardiac

List all the characteristics of Skeletal muscle tissue and where it’s found.

Striated, Voluntary, Multinucleate; found in skeletal muscles

List all the characteristics of Smooth muscle tissue and where its found

No striations, involuntary, single nucleus per cell; found in visceral organs

List all the characteristics of Cardiac Muscle Tissue and where it’s found

striated, involuntary, one nucleus per cell, intercalated discs; found in the heart

Explain what striations are

Repeating bands of protein Actin and Myosin

Explain what intercalated discs are and its function

Specialized regions running along the plasma membrane that Join adjacent cells and Assist in passing an electrical impulse

What is the function of nervous tissue and where is it found?

-Receipt, processing and transmission of information

-Found in CNS AND PNS

What are the two components of nervous tissue?

• The neuron (aka nerve cells) that transmit nerve impulses

• Glial cells (aka glia) support the cell

What is the function of the neuron and all of its components? (give the function of each component as well)

The neuron receives and transmits electrical impulses.

Components:

• Cell body (soma): contains the central nucleus

• Dendrites: receive nerve impulse

• Axon: transmit nerve impulses

The following two are glial cells

• Oligodendrocytes: insulate the axon with myelin sheath

• Astrocytes: regulate chemical environment of nerve cell

• Axon terminals: synaptic contacts from neuron to neuron