Animal Biology Test 1

What is an animal?

Eukaryotic multicellular organism that reproduces and responds to its environment

What drives evolution?

Natural Selection

Common Descent

All species are derived from a common ancestor if you go back far enough

Do organisms or populations evolve?

Populations

Natural selection takes place at the ________

Individual level

Evolution takes place at the ________

population level

Microevolution

Evolution that occurs within populations fairly quickly(allele freuqnecy shift)

Where do the changes in microevolution come from?

Mutations

Macroevolution

Evolution occurring at the species level(origination, diversification, extinction)

What is the ultimate source of heritable variation in a population?

Mutations

Which types of mutations are the ones passed to offspring?

Ones in the germline

What does the Hardy-Weinberg Equilibrium equation describe?

A population that is not evolving

What is “p” in the Hardy-Weinberg equation?

The dominant allele

What is “q” in the Hardy-Weinberg equation?

the recessive allele

What does “pq^2” represent in the hardy Weinberg equation?

The heterozygote

Genetic Drift

change of allele frequency in a gene pool due to random meeting of gametes

Bottleneck effect

An event in the environment that kills off most of the genetic variation in a population

Founder effect

A type of bottleneck where a small amount of individuals leave to populate a different place, and there gene pools become more different over time

Natural Selection

The only force that produces adaptive evolutionary changes

What are the 3 criteria for evolution by natural selection?

1. Variation of a trait
2. heritability of that trat
3. The trait changes reproductive success odds

Artificial Selection

Directional selection as dictated by humans

Sexual Selection

Selection for traits that increase access to reproductive success

Intrasexual selection

Competition; between members of the same sex

Intersexual selection

Mate choice by members of the opposite sex

What are germ cells?

Gametes

Fragmentation

A small piece of an organism splits from the main body and becomes a separate individual

Budding

Genetic material is kept in a sac attached to the organism; when conditions are right it will germinate into a new individual

What do eukaryotes do that prokaryotes do not?

Sexual Reproduction

What are the 2 biological processes involved in sexual reproduction?

* Meiotic cell division
* Formation of the female gametes

Dioecious

Reproduction necessitating 2 genetically distinct parents

Simultaneous Hermaphrodites

Animals with both male and female parts in one organism

Sequential Hermaphrodites

Genetically programmed sex change

Protogyny in sequential hermaphrodites

The organism starts as female

Protandry in sequential hermaphrodites

The organism starts as male

Advantages of simultaneous hermaphrodites?

Both sexes in a population can produce offspring

Monoecious

Using one parents to produce offspring

Is hermaphroditism mono or dioecious?

monoecious

Parthenogenesis

Development of an organism from an unfertilized egg

How is the egg formed in ameiotic parthenogenesis?

Mitosis, egg is diploid

Meiotic Parthenogenesis

The egg is haploid and formed by meiosis; sperm is absent or only there to jumpstart development

How or organisms made via meiotic parthenogenesis restored to a diploid state?

Autogamy or chromosomal duplication

Haplodiploidy

A version of meiotic parthenogenesis where __**males**__ develop from unfertilized eggs and __**females**__ form from fertilized eggs

What do males develop from in haplodiploidy?

Unfertilized eggs

What do females develop from in haplodiploidy?

Fertilized eggs

In Komodo dragons, who is the heterogametic sex?

Females(WZ)

How is diploidy restored in komodo dragons?

Autogamy: haploid ovum fuses with a polar body

Oviparity

Laying eggs after internal or external fertilization

Ovoviviparity

Eggs are kept internally until it’s time to birth(scorpions, annelids, fish, reptiles)

Viviparity

Fertilized eggs stay in the oviduct or uterus and obtain nourishment from the mother until females give live birth

Opportunistic Species(r-strategists)

Organisms that focus on high offspring output and low offspring care

Equilibrium Species(K-Strategists)

Organisms that focus on low offspring output and high offspring care

Abiotic factors(weather, natural disasters)

Density dependent, affect r-strategists more

Biotic Factors: Competition, predation, symbiosis

Density dependent factors(affect K-strategists more)

Monophyletic Tree

Includes most recent common ancestor and all of its descendants, aka a clade

Cleavage

the division of the zygote

Gastrulation

Formation of the germ layers, including the gut

Blastopore

The pocket in the gastrula that is the beginning of the gut being formed

Sperm chemotaxis

Chemical signals released by the ovum that help sperm locate it and ensure both are from the same species

Acrosomal Reaction

acrosome of the sperm pierces the outer layer of ovum and releases enzymes to digest the zona pellucida

What prevents polyspermy?

Fast and Slow block polyspermy

Fast block polyspermy

change in electrical potential of the ovum membrane so that other sperm cannot pass

Slow Block Polyspermy

Cortical granules are released between the zona pellucida and the membrane, blocking the entrance of more sperm

What is the result of slow block polyspermy?

The fertilization membrane is formed

What is the result of cleavage?

Smaller cells called blastomeres

What is the end product of cleavage?

The blastula, a hollow ball of cells

Animal Pole

mostly made of cytoplasm, divides easily

Vegetal Pole

rich in yolk, thicker, harder to divide

Polar Axis

Axis of the animal and vegetal pole

Isolethical Egg

Not a lot of yolk, but evenly distributed

What type of cleavage do isolethical eggs perform?

Radial Holoblastic Cleavage

Mesolethical egg

“medium” yolk, moderate amount of yolk at vegetal pole

How do mesolecithal eggs perform cleavage?

Radial Holoblastic Cleavage

Telolecithal Egg

Eggs with a lot of yolk at the vegetal pole

What kind of cleavage do telolecithal eggs perform?

Spiral Meroblastic Cleavage

Centrolecithal Egg

Abundant yolk in the embryonic center

What kind of cleavage do centrolecithal eggs perform?

Spiral Meroblastic Cleavage

Holoblastic Cleavage

Little amounts of yolk leads to easy cleavage that happens to the whole embryo

Meroblastic Cleavage

Abundant yolk at the vegetal pole leads to cleavage happening on the top of the undivided yolk

What kind of cleavage do protostomes perform?

Spiral cleavage

What kind of cleavage do deuterostomes perform?

Radial cleavage

What germ layers to diploblastic animals have?

* Endoderm
* Ectoderm

What germ layers do triploblastic animals have?

* Endoderm
* Ectoderm
* Mesoderm

What germinates from the ectoderm?

* Skin
* Neurons

What germinates from the mesoderm

* Notochord
* Bones
* Blood
* Facial muscles

What germinates from the endoderm?

* Stomach
* Lungs
* Thyroid

Enterocoelous

Formation of the mesoderm/coelom via outpocketing

Schizocoelous

Formation of the mesoderm/coelom via splitting; mesoderm clump lifts up and becomes a pore

Midsagittal/Sagittal plane

Right down the middle of the mirrored halves

Anterior

Towards head

Posterior

Towards tail(butt)

Transverse plane

Splits animal between top and bottom

Medial

Towards midline of body

Lateral

Towards right and left sides of body

Distal

Farther from the middle of the body

Proximal

Closer to the middle of the body

Dorsal

Towards the back/spine

Ventral

Towards the front/belly

Frontal/Coronal plane

Splits the back from the belly

Which regions are in vertebrates only?

* Pectoral Region
* Pelvic Region

pectoral Region

chest region w/ anterior appendages