Characteristics of Life A. Use Energy (the ability to do work) to grow B. Metabolism – maintain complex chemical reactions C. Homeostasis – maintain stable

LIFE IN THE MARINE ENVIRONMENTSOME BASICS OF BIOLOGY

Characteristics of Life

A. Use Energy (the ability to do work) to grow

B. Metabolism – maintain complex chemical reactions

C. Homeostasis – maintain stable internal environment

D. Respond to stimuli – sense organsE. Reproduce – pass genes on to next

generation

Energy Utilization - Organisms take in energy and transform it to do many kinds of work. This fish obtains fuel from the sea urchin and uses energy stored in the molecules of its food to power swimming and other work.

Metabolism - This protein cascade is an example of the chemical reactions that take place in organisms. The product of one reaction becomes a catalyst for a second reaction.

Homeostasis – regulatory mechanisms maintain an organism’s internal environment within tolerable limits, even though the external environment may fluctuate. In this example, regulation of the amount of salt flowing through the seagull’s body fluids is controlled by glands on the bill that excrete excess ions.

Respond to stimuli – When threatened this squid will change colors in order to blend in with it’s surroundings

Reproduce – Organisms reproduce their own kind. Life comes only from life. This humpback whale protects its offspring.

I. Building Blocks of LifeA. Major macromolecules – composed mostly of

carbon, hydrogen, oxygen, nitrogen, phosphorus1. Water is not a macromolecule but composes approx.

2/3 of living organisms2. Carbohydrates – sugars & starches

a. Energy – energy extracted from carbs. during cellular respiration is used to produce ATP.

b. Structural – cellulose, cell wall of plants; chitin, exoskeleton of insects & arthropods

Chitin a structural carbohydrate

I. Building Blocks of Life3. Proteins – most varied & complex organic

moleculesa. 20 amino acids are building blocks of

all proteinsb. Structural proteins – found in cell

membranes, muscles (actin/myosin)c. Functional – enzymes (speed up reactions but are not changed by

reactionsd. Chemical messengers – hormones,

made in one part of the body but affect another part

Muscles are mostly made up of proteins.

I. Building Blocks of Life

4. Lipids – water insoluble, fats, oils, waxesa. Major component of cell membraneb. Energy storesc. Retards evaporationd. Buoyancy – marine mammals, birdse. Hormones – cholesterol; estrogen,

testosterone

Phospholipid Bilayer

Blubber

I. Building Blocks of Life5. Nucleic Acids

a. DNA, RNA – genetic material

B. Fuel of Life – 1. ATP – energy molecule that is used in

chemical reactions2. Photosynthesis – Fig. 4.4 – Process by

which the energy from sunlight is used to covert low energy inorganic compounds to

organic compounds

a. 6CO2 + 6H2O C6H12O6 + 6O2

b. Light energy (photons) are captured

by photosynthetic pigments, chlorophyll a is primary pigment

c. Autotrophs – make own food heterotrophs – must obtain energy from

outside sources

I. Building Blocks of Life

Photosynthesis

I. Building Blocks of Life 3. Respiration - Fig. 4.6 – process in which organic compounds are broken down to

in order to release energy a. C6H12O6 + 6O2 6CO2 + 6H2O + 36ATP

b. Energy recycles – Fig. 4.5i. Aerobic respiration – requires

O2

ii. Anaerobic respiration – no O2

required4. Primary Productivity – net gain in organic matter results when the rate of photosynthesis is greater than the rate of respiration

Cellular Respiration

II. Living Machinery Organic molecules are organized into

structural & functional units

Molecules organelles cells tissues organ systems organism populations communities ecosystems

A. Cells & Organelles – the cells is the smallest unit of life, organelles within the cells are specialized for

particular tasks

II. Living Machinery 1. Prokaryotic cells – Fig. 4.7

Lack a membrane bound nucleus & membrane

bound organelles(ex - bacteria), have genetic

material; photosynthesis or chemosynthesis

takes place on the cell membrane; have a cell wall; some have flagellum for locomotion

Prokaryotic Cell

II. Living Machinery 2. Eukaryotic cells – Fig. 4.8 Have a membrane bound nucleus

and organelles

a. Nucleus – control center b. Endoplasmic reticulum (ER) – packages organic molecules c. Golgi complex – packages &

ships d. Mitochondria – site of cell resp.

II. Living Machinery e. Chloroplasts – site of photo.f. Cell wall – protectsg. Cell membrane – regulates what

enters & leaves the cell

B. Levels of Organization – Table 4.1

Eukaryotic Cell - Animal

Eukaryotic Cell - Plant

Challenges of Life in the Sea

Organisms have evolved numerous adaptations that allow them to live in a wide variety of habitats – Must maintain homeostasis - planktonic – drift with currents

- benthic – live at the bottom of ocean - nekton – organisms that can swim


planktonicBenthic

nekton


A. Salinity – avg. 35% - most organisms must maintain lower body salt concentration than ocean1. diffusion – movement of molecules

down their concentration gradient; no energy required; osmosis – diffusion of water

2. osmoconformers – organisms that do not actively maintain salt and water balance, their internal concentrations change as salinity of water changes

Challenges of Life in the Sea3. osmoregulators – control the concentration

of their internal environment4. hypotonic – a solution that has a lower concentration of solutes that that of a cell

placed into it; therefore water moves into the cell

causing it to burst isotonic – concentration of solutes and

water equal that of the cell, therefore no net

movement of water hypertonic – a solution that has a higher

solute concentration than that of a cell placed

into it, therefore water moves out of the cell



Challenges of Life in the Sea5. Marine fish – have a lower salt

concentration than seawater, therefore tend to loose water; adaptations to maintain homeostasis include (Fig. 4.14)Drinks seawaterExcretes excess salt through gillsExcretes small volumes of concentrated salty

urine

Challenges of Life in the Sea5. Fresh water fish – higher salt concentration

that fresh water, therefore tend to gain water; adaptations to maintain homeostasis includeDoes not drink waterSalt absorbed by gillsExcretes large volumes of dilute urine

Challenges of Life in the Sea6. Adaptations of other

marine organismsSea turtles/sea

gulls/sea lions have glands near the eyes that excrete “salty” tears (Fig. 4-15)

Mangroves/spartina grass – excrete excess salt through leaves

Salt crystals on spartina grass

Challenges of Life in the SeaB. Temperature – most metabolic reactions proceed

faster at higher temps. (up to a point)1. Terms to describe temp. of body

a. Poikilothermy – having a body temp. that changes with that of the environment

b. Homeothermy – maintenance of a constant high body temp. & metabolic rate

2. Terms to describe where the body heat comes froma. Ectotherm – an animal that must use

environmental energy and behavioral adaptations

to regulate body temp.b. Endotherm – an animal that uses metabolic

energy to maintain a constant body temp.


Angel Fish – poikilotherm, exothermic

Walrus – homeotherm, endothermic

Challenges of Life in the Seac. Surface area to volume ration – determines

how rapidly heat and materials flow in & out of

organisms (Fig. 4.17)- larger organisms have smaller SA/V

than smaller organisms

- smaller organisms can rely on diffusion alone

- larger organisms must rely on well developed

respiratory; circulatory, and digestive systems


IV. Perpetuating Life

A. Modes of reproduction1. Asexual – offspring are genetically identical to

parenta. Binary fission – bacteria and some

fungi; division of parent cell into 2 equal

daughter cells

b. Budding – sea anemone; division of parent cell

into 2 unequal daughter cells


Binary fission in a bacterium

Budding in yeast

2. sexual – offspring are genetically

uniquea. Gametes (sex cells)

are formed by meiosis (reduction division)

b. Fertilization – fusion of

gametes to produce a zygote

c. Zygote divides to produce

embryo


B. Reproductive Strategies1. external fertilization/external

development; fishes & frogs

- parents don’t help- large numbers of egg & sperm

released- death from disease/predation is high


2. internal fertilization/external development; birds/reptiles

- sometimes parents raise young- smaller brood sizes than fish/amp.- lower death rate than fish/amp.

3. internal fertilization/internal development; some

fish/mammals- parents play very active role in raising

young- small litters- higher survival rate


IV. Perpetuating LifeExternal fertilization – External Development

IV. Perpetuating LifeInternal fertilization – External development

IV. Perpetuating LifeInternal fertilization – Internal development

A. Evolution – theory that all species evolved from a pre-existing species; natural selection is the

process by which evolution occurs; traits are selected for or against, this results in some characteristics being passed on to future generations and some are not

B. Classifying Living Things – phylogeny is the evolutionary history of a species1. binomial nomenclature – a two named system developed by Linnaeus2. What do scientists look at when classifying?

- comparative anatomy- comparative biochemistry (DNA/RNA)- Embryology- Cytology- Fossil record

3. Taxonomic Levels – See Table 4.2

V. Diversity of Life in the Sea


Comparative Anatomy Comparative Biochemistry


Comparing Fossils Comparative Embryology



V. Diversity of Life


Documents

Characteristics of Life A. Use Energy (the ability to do work) to grow B. Metabolism – maintain complex chemical reactions C. Homeostasis – maintain stable