Part of slides 4-7

Animal form and function is correlated at

All levels of organization

Hierarchy of organization

Cells --> tissues --> organs --> organ systems --> organisms

Relationship between structure and function

STRUCTURE determines FUNCTION

4 types of animal tissue

1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
4. Nervous tissue

Epithelial tissue

- Occur as sheets of cells on the outside of the body --> line certain cavities
- Serve mostly as a form of protection (ex. prevents water loss or pathogens entering the entity) --> acts as a barrier and separates certain parts from each other

Connective tissue

Connective tissue

Supports, protects, and gives structure to other tissues and organs in the body --> composed of 3 fibers (collagenous, elastic, and reticular)

Collagenous fibers

Connect things together

Elastic fibers

Give elasticity to the tissue itself

Reticular fibers

Join tissue to adjacent tissues

Muscle tissue

Have filaments which contain the proteins ACTIN and MYOSIN, which allow muscles to EXPAND and CONTRACT

Nervous tissue

Have 2 basic components --> glial cells and neurons

Glial cells

Support the neurons

Neurons

Transmit information (axons = transmit signals, multiple neurons = nerves --> can then form a central nervous system)

Importance of exchange

Primary mechanism for how organisms obtain the things they need or get rid of waste --> ex.) food; heat exchange --> could be internal ( relative to a particular environment) or external

Rate of exchange is proportional to

surface area

Amount of material exchanged is proportional to

Volume

When you have a higher SA:V ratio...

Your rate of exchange will be HIGH (MORE EFFICIENT) relative to the amount of material you need to exchange --> when you have a lot of material to exchange but do not have the ability/facilities to do so (quickly), then it is going to be a lot more difficult to exchange with the environment, especially if you are a larger organism

Organization of simpler organismic structures

Lack complex internal organization --> do not have as advanced structures for exchange --> some structures have ADAPTED to such circumstances, ex.) FOLDS which increase surface area (INC. SA = MORE EFFICIENT)

Why can't we have massive unicellular organisms (ex. giant amoebas)?

Internal structure is required for bigger size --> there would be too much volume, so the organism would not be able to exchange materials fast enough to live

Why are some surfaces for environmental exchange extensively branched and/or folded?

B/c it creates more SURFACE AREA --> accomplished through certain structures (ex. GILLS in axolotls

Internal body fluids link exchange surfaces to...

BODY CELLS --> 2 types:
1. Interstitial fluid
2. Circulatory fluid

Complex body plans can help...

Maintain HOMEOSTASIS

What systems help control bodily exchange

1. Endocrine system
2. Nervous system

Endocrine system

- Signaling molecules (hormones) released into the bloodstream by endocrine cells are carried to all locations in the body
- Ex.) Similar to posting on social media
- Hormones have distinct effects, only cells with the appropriate cells respond
- Coordinate changes that affect the whole body

Nervous system

Neurons transmit signals along dedicated routes connecting specific locations in the body
- Ex.) Similar to making a phone call
- The pathways used by the signal convey information
- Immediate and rapid responses to the environment

Diet of an organism must supply

1. Chemical energy: Body needs energy to function
2. Organic building blocks: We have to produce, heal, and grow structures in our body --> essential nutrients (gained in FOOD)

Essential nutrients

Substances which are required, but cannot be assembled from simple, organic molecules (i.e. they have to be eaten)

Steps of food processing

1. Ingestion
2. Digestion
3. Absorption
4. Elimination

Ingestion

The process of taking food, drink, or another substance into the body by swallowing or absorbing --> 4 main types

4 main types of ingestion

1. Filter feeding
2. Substrate feeding
3. Bulk feeding
4. Fluid feeding

Filter feeding

Filtering small bits from the environment --> ex.) Baleen whales have a filter around the edges of their mouth that sorts through sea water --> pushes seawater out after filtering for food

Substrate feeding

Substrate feeding

Live on or in their food source --> ex.) earthworms and caterpillars

Bulk feeding

Ingest large pieces of food --> ex.) humans and cows

Fluid feeding

Predominantly fluid diet --> suck nutrient-rich fluids from a living host --> ex.) spiders and hummingbirds

Digestion

- Food is broken down into molecules small enough for absorption
- Mechanical and chemical processes
- Chemical (enzymatic) breakdown: "HYDROLYSIS"