Bio 111 Exam 2

development

produces organisms with a defined set of characteristics

growth

increase in size or number of cells

Morphology

structure or form of an organism

Hox genes

series of genes that controls the differentiation of cells and tissues in an embryo

how many planes do our body have?

3

what are the purpose of having different plane/axis?

direct and control tissue

how do cell receives information?

concentration of intercellular and extracellular molecules

morphogens (intracellular)

Signaling molecules that stimulate cell differentiation and development

cell adhesion molecules (CAMs)

-proteins found on surface of most cells

-aid in binding the cell to the extracellular matrix or to other cells

- present with cell to cell contacts

effect of cell positional information

- cell migration within the embryo

- division

- apoptosis: separate tissue

- cellular differentiation: stem cells are being use for different purpose

How is cells distribute asymmetrically?

concentration gradient, positional information

How are the position influenced?

contacts it makes with other cells and extracellular matrix

transcription factor

A regulatory protein that binds to DNA and affects transcription of specific genes.

Tripoblastic

having 3 germ layers: ectoderm, mesoderm, and endoderm

5 stages of embryogenesis

1. fertilization

2. cleavage

3. gastrulation

4. neurulation

5. organogenesis

sometimes metamorphosis

what do sperm use to break through the jelly coat of egg?

hydrolytic enzymes

what happen when sperm enters the egg?

the egg is depolarized to block additional sperm

cleavage

- repeated mitotic cell divisions without cell growth

- daughter cells are blastomere

- solid ball of cells hollows out to form blastula

meroblastic cleavage

incomplete division of the egg, occurs in species with yolk-rich eggs, such as reptiles and birds

vegetal pole

The portion of the egg where most yolk is concentrated

animal pole

The portion of the egg where the least yolk is concentrated and more cytoplasm in egg

holoblastic cleavage

- complete cleavage

- smaller amount of yolk

- amphibians and mammals

- mammal undergo compaction forming a blastocyst

Blastocyst

stage of early development in mammals that consists of a hollow ball of cells

Gastrula

An embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm.

Ectoderm

- outer layer

- skin

- nervous system

Mesoderm

- middle layer

- heart

- limbs

- muscles

- kidneys

- blood

- connective tissues

- notochord

Endoderm

- inner layer

- form lining of gut, liver, pancreas, thyroid, lungs, and bladder

where does cell derived from?

germ layers

Blastopore

the opening of the central cavity of an embryo in the early stage of development.

blastopore (human anus)

the first opening that forms on the surface of an early animal embryo during the gastrulation stage. It connects the embryo's inside cavity to the outside world

Archenteron

the primitive gastric cavity of an embryo

when is gastrulation complete?

when the 3 germ layers are present

what is the precursor for all nerve?

neural crest and the ectoderm

neural tube

an embryonic structure that gives rise to the central nervous system

what do embryo develops during the neuralation?

segmented structures

how does the neural tube form?

1. thickening and elongation

2. folding

3. convergence

4. fusion

what happen in thickening and elongation?

- Ectoderm thickens over the notochord.

- This forms the neural plate.

- The surrounding ectoderm becomes the neural crest and epidermis.

what happen in folding?

- Cells in the middle (medial hinge point) change shape.

- The neural plate folds upward.

- This creates a neural groove.

what happen in convergence?

- The two sides of the neural plate move toward each other.

- Dorsal lateral hinge points help the sides bend inward.

- The folds meet and form a tube-like structure.

what happen in fusion?

- The two sides fuse together.

- This closes the neural tube.

- The epidermis closes over the top.

- Neural crest cells separate and migrate away.

what happen when the neural tube doesn't close all the way?

nutrition deficiency or paralysis

neural crest

- cells on the dorsal side of the neural tube

- unique to vertebrates

- migrate to different regions of the embryo

- from neurons and supporting cells of the peripheral nervous system (PNS)

what does neural crest form?

- peripheral nervous system (PNS): neuron forming and supporting cells

- melanocytes: skin pigment

- facial skeleton and cartilage: face and skull forma

- medulla of the adrenal gland: inner part of adrenal gland

how are segments form?

dividing blocks of mesoderm into somites become ribs, intercostal muscles, and vertebrae

when does organ form?

during or after neurulation

what controls and organize organ development?

hox genes

when does life emerged?

between 4 and 3.5 bya

what do you need before you can have a living cell?

1. polymers

2. information transfer

3. membrane to protect you from damage

4. cellular properties

stages that first cell might have arisen

1. nucleotides and amino acids produced

2. nucleotides and amino acids became polymerized to form DNA, RNA, and proteins

3. polymers became enclosed in membrane (copy molecule)

4. polymers enclosed in membranes acquired cellular properties

how does organic molecules form on earth?

earth may have been more conductive to spontaneous formation of organic molecules

what are the hypotheses of how life were created on earth?

1. reducing atmosphere: stanley miller

2. extraterrestrial: meteorites brought C to earth

3. deep sea vent: molecule formed between extremely hot water vent and cold ocean water

Europa

moon of jupiter

enceladus

Moon of Saturn

where did the organic polymers come from?

clay surface of shallow pools

characteristics of protobiont

1. Boundary separated external environment from internal contents

2. Polymers inside contained information

3. Other polymers had enzymatic function

4. capable of self-replication

Coacervates

droplets that form spontaneously from the association of charged polymers. enzymes trapped inside can perform primitive metabolic function. basically charged ball

liposomes

vesicles surrounded by a lipid layer. clay can catalyze formation of liposomes that grow and divide. can enclose RNA.

Central Dogma

DNA -> RNA -> Protein

what does scientist expect molecule to be able to do?

- store information

- self replicate

- have enzymatic function

what was the first macromolecule of probiotants and why?

RNA because it can store information, self replicate, and have enzymatic function

what can fossils tell us about early earth?

life, climate, and geography

what type of rocks contain most fossil?

sedimentary rocks

how can fossil be dated?

radiometric dating

can anything become a fossil?

no

Hadean Eon

no life on earth

Archean Eon

only prokaryotes

Proterozoic Eon

- first eukaryotes

- multicellular eukaryotes

- define animals: sponges and jellyfish

Phanerozoic Eon

- cambrian explosion of animals; land and plants came later

macroevolution/ major environmental changes can caused by

- climate/temperature, glaciation

- atmosphere, oxygen, humidity, light penetration

- movement of land masses

- floods

- volcanic eruptions

- metrorics impacts

5 mass extinctions

Ordovician, Devonian, Permian, Triassic, Cretaceous

Hetrotroph cells

fed on organic molecules

autotroph cells

evolved as a supply of organic molecules

stomatolites

Rocks built up by ancient photosynthetic prokaryotes (layered) first evidence of life on Earth. Calcium carbonate. produced oxygen as a waste product of photosynthesis.

Mesozoic Era

- dinosaurs

- true mammals

- early birds

- flowering plants

Cenozic Era

- mammals expanded quickly

- angiosperms dominate land plants

- hominids

Homo erectus

- normal size but smaller brain

- use tools, hunted animals, and cook over fires

- extinct abt 100,000 ya

Homo heidelbergensis

- same body and barin size as human

- use tools to hunt

- gave rise to 3 species: H. neanderthalis, the denisovans, and H. sapiens

Homo neanderthalis

- shorter and stockier than heidelbergensis

- conserving heat better

- massive skull and larger brain size

- live in europe

- hyoid bone= speech was used

Homo sapiens

- smaller brain

- body required lower energy

- increased longevity

- social structures and cultural adaptations

does physical differences reflect genetic differences?

no

inherited traits

traits that are passed from parents to their offspring

what is the cause of adaptive evolution?

natural selection

what is natural selection

A natural process resulting in the evolution of organisms best adapted to the environment.

what did darwin notice in population?

variation

2 important points that darwin made

1. modern species have descended from common ancestors

2. natural selection is the mechanism of evolution

populations produce more individuals that can survive =

competition was a factor for all living things

natural selection can lead to ________

evolution

transitional forms

fossils that connect ancestral species with their descendants through a series of tiny steps

Biogeography and its impact on evolution

Study of past and present distribution of organisms. isolated continents and island groups evolve their own distinct plant and animal communities

homology

similarity resulting from common ancestry

vestigial structures (anatomical homology)

A structure that is present in an organism but no longer serves its original purpose

developmental homology

A similarity in embryonic form, or in the fate of embryonic tissues

molecular homology

many species share similar DNA and amino acid sequences. (replication, transcription, translation, respiration, and membrane transport)

Microevolution

Change in allele frequencies in a population over generations.

Alleles

Different forms of a gene

allele frequency

# of copies of an allele/total # of alleles in population

Population

A group of individuals that belong to the same species and live in the same area

gene pool

Combined genetic information of all the members of a particular population

Polymorphism

two or more variations for a given character

polymorphic gene

two or more alleles